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Title: The Progress of the Century

Contributor: Alfred Russel Wallace
Alexander V. G. Allen
Edward Caird
Thomas Curtis Clarke
Sir Charles Wentworth Dilke
James Gibbons
Richard J. H. Gottheil
William W. Keen
Andrew Lang
Sir Norman Lockyer
A. T. Mahan
Thomas C. Mendenhall
Sir William Osler
W. M. Flinders Petrie
William Ramsay
Goldwin Smith
Elihu Thomson

Release date: September 14, 2017 [eBook #55546]
Most recently updated: October 23, 2024

Language: English

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*** START OF THE PROJECT GUTENBERG EBOOK THE PROGRESS
OF THE CENTURY ***

THE PROGRESS
OF THE

CENTURY

BY ALFRED RUSSEL WALLACE; PROF. WILLIAM RAMSAY;
PROF. WILLIAM MATTHEW FLINDERS-PETRIE; SIR JOSEPH
NORMAN LOCKYER; EDWARD CAIRD; WILLIAM OSLER;
W. W. KEEN; PROF. ELIHU THOMSON; PRESIDENT THOMAS
CORWIN MENDENHALL; SIR CHARLES WENTWORTH DILKE;
CAPTAIN ALFRED T. MAHAN; ANDREW LANG; THOMAS C.
CLARKE; CARDINAL JAMES GIBBONS; REV. ALEXANDER

V. G. ALLEN; PROF. RICHARD J. H. GOTTHEIL; PROF.
GOLDWIN SMITH

NEW YORK AND LONDON
HARPER & BROTHERS PUBLISHERS
1901

Copyright, 1901, by Harper & Brothers.
Copyright, 1901, by The Sun Printing and Publishing Association.
All rights reserved.

CONTENTS
PAGE
EVOLUTION. By Alfred Russel Wallace, LL.D.,
D.C.L., F.R.S 3

CHEMISTRY. By Prof. William Ramsay, Ph.D.,
F.R.S., F.C.S., Officer of the Legion of Honor 33

ARCHÆOLOGY. By Prof. William Matthew
Flinders-Petrie, D.C.L., LL.D., Edwards
Professor of Egyptology, University College,
London 73

ASTRONOMY. By Sir Joseph Norman Lockyer,
C.B., F.R.S., Director of Solar Physics
Observatory, South Kensington 105

PHILOSOPHY. By Edward Caird, LL.D., D.C.L.,
Professor of Moral Philosophy, Glasgow 145

MEDICINE. By William Osler, LL.D., Professor
of Medicine and Physician to Hospital, Johns
Hopkins Medical School 173

SURGERY. By W. W. Keen, M.D., LL.D., F.R.C.S.
(Hon.), Professor of the Principles of Surgery
and of Clinical Surgery, Jefferson Medical
College, Philadelphia 217

ELECTRICITY. By Prof. Elihu Thomson, A.M.,
Ph.D., Chevalier and Officer of the Legion of
Honor 265

PHYSICS. By President Thomas Corwin
Mendenhall, Ph.D., D.Sc., LL.D., Member
National Academy of Science 303

WAR. By the Right Hon. Sir Charles Wentworth
Dilke, LL.M. 333

NAVAL SHIPS. By Captain Alfred T. Mahan, late
U.S.N., D.C.L., LL.D. 355

LITERATURE. By Andrew Lang, Hon. Fellow
Merton College, Oxford 389

ENGINEERING. By Thomas C. Clarke. Past
President of the American Society of Civil
Engineers 421

RELIGION:
Catholicism. By Cardinal James Gibbons 455

Protestantism. By Rev. Alexander V. G.
Allen, Professor of Church History in the
Episcopal Theological School at
Cambridge, Mass. 477

The Jews and Judaism. By Professor Richard
J. H. Gottheil 498

Free-Thought. By Professor Goldwin Smith 539

EVOLUTION

Among the great and fertile scientific conceptions which have either
originated or become firmly established during the nineteenth
century, the theory of evolution, if not the greatest of them all, will certainly
take its place in the front rank. As a partial explanation (for no complete
explanation is possible to finite intelligence) of the phenomena of nature, it
illuminates every department of science, from the study of the most remote
cosmic phenomena accessible to us to that of the minutest organisms
revealed by the most powerful microscopes; while upon the great problem
of the mode of origin of the various forms of life—long considered
insoluble—it throws so clear a light that to many biologists it seems to
afford as complete a solution, in principle, as we can expect to reach.

THE NATURE AND LIMITS OF EVOLUTION

So many of the objections which are still made to the theory of
evolution, and especially to that branch of it which deals with living
organisms, rest upon a misconception of what it professes to explain, and
even of what any theory can possibly explain, that a few words on its nature
and limits seem to be necessary.
Evolution, as a general principle, implies that all things in the universe,
as we see them, have arisen from other things which preceded them by a
process of modification, under the action of those all-pervading but
mysterious agencies known to us as “natural forces,” or, more generally,
“the laws of nature.” More particularly the term evolution implies that the
process is an “unrolling,” or “unfolding,” derived probably from the way in

which leaves and flowers are usually rolled up or crumpled up in the bud
and grow into their perfect form by unrolling or unfolding. Insects in the
pupa and vertebrates in the embryo exhibit a somewhat similar condition of
folding, and the word is therefore very applicable to an extensive range of
phenomena; but it must not be taken as universally applicable, since in the
material world there are other modes of orderly change under natural laws
to which the terms development or evolution are equally applicable. The
“continuity” of physical phenomena, as illustrated by the late Sir William
Grove in 1866, has the same general meaning, but evolution implies more
than mere continuity or succession—something like growth or definite
change from form to form under the action of unchangeable laws.
The point to be especially noted here is, that evolution, even if it is
essentially a true and complete theory of the universe, can only explain the
existing conditions of nature by showing that it has been derived from some
pre-existing condition through the action of known forces and laws. It may
also show the high probability of a similar derivation from a still earlier
condition; but the further back we go the more uncertain must be our
conclusions, while we can never make any real approach to the absolute
beginnings of things. Herbert Spencer, and many other thinkers before him,
have shown that if we try to realize the absolute nature of the simplest
phenomena, we are inevitably landed either in a contradiction or in some
unthinkable proposition. Thus, suppose we ask, Is matter infinitely
divisible, or is it not? If we say it is, we cannot think it out, since all infinity,
however it may be stated in words, is really unthinkable.
If we say there is a limit—the ultimate atom—then, as all size is
comparative, we can imagine a being to whom this atom seems as large as
an apple or even a house does to us; and we then find it quite unthinkable
that this mass of matter should be in its nature absolutely indivisible even
by an infinite force. It follows that all explanations of phenomena can only
be partial explanations. They can inform us of the last change or the last
series of changes which brought about the actual conditions now existing,
and they can often enable us to predict future changes to a limited extent;
but both the infinite past and the remote future are alike beyond our powers.
Yet the explanations that the theory of evolution gives us are none the less
real and none the less important, especially when we compare its teachings
with the wild guesses or the total ignorance of the thinkers of earlier ages.

THE RISE AND PROGRESS OF THE IDEA OF
EVOLUTION

If we trace, however briefly, the gradual development of knowledge
and speculation on this subject, we shall perhaps appreciate more fully the
advance we have really made during the present century.
The first speculations on the nature and source of the phenomena of the
universe, of which we have any knowledge, are those of the early Greek
philosophers, such as Thales, Anaximander, Anaxagoras, and Empedocles;
but as the more important of their teachings are embodied, with some
approach to system and with much acuteness of reasoning, in the great
poem of the Latin author Lucretius, “On the Nature of Things,” it will be
sufficient to give a sketch of his main conclusions, making use of the
excellent prose translation by Mr. H. A. J. Munro, of Trinity College,
Cambridge.
Lucretius had a very clear idea of the indestructibility of matter. He
argues that things cannot have come out of nothing, and he says: “A thing
never returns to nothing, but all things, after disruption, go back into the
first bodies of matter.” He then argues that, as the actual processes of
growth, decay, and other natural changes are imperceptible to us, therefore
“Nature works by unseen bodies.” He justly claims great importance for the
demonstration of the fact that in all matter whatever, however solid and
hard it may be, there are vacancies, or, as he expresses it, “Mixed up in all
things there is void or empty space.” He thus anticipated the modern
doctrine that the molecules of matter do not come into actual contact. He
then defines atoms thus: “First bodies are solid and without void”; and as
nothing can be produced from nothing, he concludes that these first bodies
(atoms or molecules) must be everlasting, and that they supply matter for
the reproduction of all things.
He then goes on to prove that these “first beginnings are of solid
singleness, not formed of parts, but strong in everlasting singleness.” He
further proves that these “first beginnings” (atoms) cannot be infinitely
small, and also that the universe cannot be limited—that it is infinite. He
thus anticipated the main ideas as to atoms and the universe which have
been held by most materialistic thinkers down to our own times.

Lucretius was an absolute materialist, for though he did not deny the
existence of the gods he refused them any share in the construction of the
universe, which, he again and again urges, arose by chance, after infinite
time, by the random motions and collisions and entanglements of the
infinity of atoms. He assumes some forces analogous to gravitation and the
molecular motions of gases in the following passage: “For the first
beginnings of things move first of themselves; next these bodies which
form a small aggregate and come nearest, so to say, to the powers of the
first beginnings are impelled and set in movement by the unseen strokes of
these first bodies, and they next in turn stir up other bodies which are a little
larger.”
He also anticipated Galileo as to the equal speed of all falling bodies
when not checked by the air in the following precise statement: “For
whenever bodies fall through water and thin air they must quicken their
descents in proportion to their weights, because the body of water and
subtle nature of air cannot retard everything to an equal degree; on the other
hand, empty void cannot offer resistance to anything in any direction at any
time, but must continually give way; and for this reason all things must be
moved and borne along with equal velocity, though of unequal weights,
through the unresisting void.”
This is a wonderfully accurate general statement of the equal rate of
motion of all kinds of matter under the same forces; and when we consider
that there is no indication of any experimental basis for this conclusion, and
that nothing equivalent to our sciences of physics or chemistry existed, we
are amazed at the general correctness of many of his views, derived solely
by a process of reasoning from the most obvious phenomena of nature. He
argues that, given infinite matter and space and inherent motion, “things
must go on and be completed,” and his general conclusion is thus
expressed: “If you will apprehend and keep in mind these things, nature,
free at once and rid of her haughty lords, is seen to do all things
spontaneously of herself without the meddling of the gods.”
It is when he attempts to deal with the origin of living organisms that
the absence of all knowledge of chemistry, physiology, and histology
renders his task impossible and leads him into what seem to us the wildest
absurdities. He has an elaborate but very unconvincing argument that
sensation can arise out of atoms which have no sensation; and, taking the

appearance of worms, etc., in the earth and in putrid matter as a proof that
they are still actually produced de novo in it, he argues that at some remote
epoch the now worn-out earth was more fertile, and produced in like
manner all kinds of animals. The first human infants he supposes to have
been formed at some very remote time in the manner following: “For much
heat and moisture would then abound in the fields; and therefore wherever a
suitable spot offered wombs would grow, attached to the earth by roots; and
when the warmth of the infants, flying the wet and craving the air, had
opened these in the fulness of time, nature would turn to that spot the pores
of the earth and constrain it to yield from its opened veins a liquid most like
to milk. To the children the earth would furnish food, the heat raiment, the
grass a bed rich in abundance of soft down.... Wherefore, again and again I
say, the earth, with good title, has gotten and keeps the name of mother,
since she of herself gave birth to mankind, and at a time nearly fixed shed
forth every beast that ranges wildly over the great mountains, and at the
same time the fowls of the air with all their varied shapes.”
The fact that this mode of origin commended itself to one of the
brightest intellects of the first century B. C., enlightened by the best thought
of the Grecian philosophers, may enable us the better to appreciate the
immense advance made by modern evolutionists.

THE FIRST REAL STEPS TOWARDS EVOLUTION

We have now a great blank of fifteen centuries—the dark ages of
human progress—after which the era of observation and experiment began,
and for the first time men really set themselves to study nature, thus laying
the foundation for all the great theoretical advances of our time. As leading
to the next great step in theories of evolution, we must note the life-long
observations by Tycho Brahe of the apparent motions of the planets; the
grand discovery of Kepler that all these apparently erratic motions were due
to their revolution round the sun in elliptic orbits, with a fixed relation
between their distance from the sun and their periods of revolution; and
Newton’s epoch-making theory of universal gravitation by which all these
facts and many others since discovered were harmonized and explained.

But all this implied no law of development, and it was long thought that
the solar system was fixed and unchangeable—that some altogether
unknown or miraculous agency must have set it going, and that it had in
itself no principle of change or decay, but might continue as it now is to all
eternity. It was at the very end of the eighteenth century that Laplace
announced his “Nebular Hypothesis,” the first attempt ever made to explain
the origin of the solar system under the influence of the known laws of
motion, gravitation, and heat, acting upon an altogether different antecedent
condition of things—a true process of evolution.
Laplace supposed that the whole matter of the solar system was once in
a condition of vapor, and that it formed an enormous nebulous mass many
times larger than the then known dimensions of the planetary sphere. He
showed how, under the influence of gravitation, this nebula would
condense, and that such irregularities of motion and density as would be
sure to exist would lead to rotation of the mass. Under the law of gravitation
this would lead to outer rings being left behind by the contraction of the
central mass, which rings would at a later period become drawn together at
some point of initial greater density and thus form planets. The whole
process is admitted to be mathematically demonstrable, given the initial
conditions; but recent extensions of our knowledge of the interplanetary and
interstellar spaces have shown that the supposed void is really full of
invisible solid matter, ranging from the bulk of the smaller planets down to
the finest dust, and it is very difficult to imagine any possible causes which
would keep all the solid matter of the system in a state of vapor, when
subject, on the confines of the mass, to the cold of interstellar space. The
antecedent condition of our system is now thought to have been either
wholly or partially meteoritic, but in either case we have a genuine theory
of its evolution which has now been so extended as to include the
appearance of comets and meteors, of nebulæ, and star clusters, of
temporary, periodic, and colored stars, and many other phenomena of the
stellar universe. It is no objection to these grand theories to urge that they
do not explain the origin of the matter of the universe, either what it is or
how it came to be where we now find it. We can only take one step at a
time, and even if in these greater problems any further advance should be as
yet denied us, it is still a great thing to have been able to take even one
secure step into the vast and mysterious depths of the interstellar spaces.

EVOLUTION OF THE EARTH’S CRUST

Although Pythagoras (500 B. C.) believed that sea and land must often
have changed places, and a few other observers at different epochs came to
the same conclusion, yet, till quite recent times, the earth was generally
supposed to have been always very much as it is now; people spoke of “the
eternal hills”; and the great mountain ranges, the mighty ravines and
precipices, as well as the deep seas and oceans, were believed to be the
direct work of the Creator.
It was only in the latter half of the eighteenth century that a few
observers began to see the importance of studying the nature of the earth’s
crust, so far as it could be reached in ravines, quarries, and mines; and one
of the most earnest of these students, Dr. Hutton, of Edinburgh, after more
than thirty years of travel and study, published his great work, The Theory
of the Earth, which must be considered to be the starting-point of modern
geology. He maintained that it was only by observing causes now in action
that we can explain the phenomena presented by the stratified and igneous
rocks; he showed that the former must have been laid down by water, and
that the larger part of them, containing as they do marine shells and other
fossils, must have been deposited on the sea-bottom. He showed how rain
and rivers, frost and snow, wind and heat disintegrated the hardest rocks
and would in time excavate the deepest valleys; while earthquakes, however
small an elevation any one of them might produce, would in time raise the
sea-bottom sufficiently high to form, when denuded, mountain ranges,
plains, and valleys like those we now see everywhere upon the earth’s
surface. He also showed that the most ancient stratified rocks, those that lie
at the very base of the series, presented every indication of having been
formed in exactly the same way as the most recent ones. Hence he stated a
conclusion which excited a storm of opposition, in these words: “In the
economy of the world I can find no traces of a beginning, no prospect of an
end.” This was thought to imply a denial of creation, and was quite
sufficient at that period to prevent the work of any man of science from
being judged impartially.
But although Playfair and a few others upheld Hutton’s views, they
were too novel to receive much support by his contemporaries, and this was
especially the case as regards the slow and continuous action of existing

causes being sufficient to account for all the known phenomena presented
by the crust of the earth. Hence the belief in catastrophes and cataclysms—
in great convulsions tearing mountains asunder, and vast floods sweeping
over whole continents—continued to prevail, till finally banished by the
genius and perseverance of one man, Sir Charles Lyell. His Principles of
Geology was first published in 1830, and successive editions, revised and
often greatly extended, continued to appear till the author’s death, forty-five
years later. As this work affords a fine example of the application of the
principles of evolution to the later phases of the earth’s history, and as it not
only revolutionized scientific opinion in its own domain, but prepared the
way for the acceptance of the still more novel and startling application of
the same principles to the entire organic world, it will be necessary to show
what opinions prevailed at the time it first appeared in order that we may
understand how great was the change it effected.
In the earlier years of the nineteenth century the standard geological
work, both in Great Britain and on the Continent, was Cuvier’s Essay on the
Theory of the Earth. In 1827 a fifth edition of the English translation
appeared, and there was a German translation so late as 1830—sufficient
proofs of its wide popularity. Yet this work abounds in statements which are
positively ludicrous to any one conversant with modern geology. It never
appeals to known causes, but again and again assumes forces to be at work
for which no evidence is adduced and which are totally at variance with
what we see in the world to-day. A few examples justifying these statements
must be here given. Cuvier shows that he was acquainted with the theory of
modern causes, but he altogether rejects it, saying that “the march of nature
is changed, and none of the agents she now employs would have been
sufficient for the production of her ancient works.” He adduces “the
primitive mountains” whose “sharp and bristling ridges and peaks are
indications of the violent manner in which they have been elevated.” He
allows that atmospheric agencies may form sea-cliffs, alluvial deposits, and
taluses of loose matter at the foot of the precipices, but he adds: “These are
but limited effects to which vegetation in general puts a stop, and which,
besides, presuppose the existence of mountains, valleys, and plains—in
short, all the inequalities of the globe—and which, therefore, cannot have
given rise to those inequalities.” He contrasts the calm and peaceful aspect
of the surface of the earth with the appearances discovered when we
examine its interior. Here, in the raised beds of shells, the fractured rocks,

the inclined or even vertical stratification, he finds abundant proofs “that
the surface of the globe has been broken up by revolutions and
catastrophes.”
He also refers to the numerous large blocks of the primitive rocks
scattered over the surface of secondary formations, and separated by deep
valleys or even by arms of the sea from the peaks or ridges from which they
must have been derived, as further proofs of catastrophes; for, it is argued,
they must have been either ejected by volcanic eruptions or carried by
waters, which, in either case, “must have exceeded in violence anything we
can imagine at the present day,” and he therefore concludes that “it is in
vain we search among the powers which now act upon the surface of the
earth for causes sufficient to produce the revolutions and catastrophes, the
traces of which are exhibited in its crust.” He is quite confident that all
these changes go on rapidly, periods of catastrophe alternating with periods
of repose. The present surface of the earth he holds to be quite recent, and
he maintains “that, if anything in geology be established, it is that the
surface of our globe has undergone a great and sudden revolution, the date
of which cannot be referred to a much earlier period than five or six
thousand years ago; that this revolution overwhelmed and caused to
disappear the countries which were previously inhabited by man, and the
species of animals now best known; that, on the other hand, it laid dry the
bottom of the last sea, and formed of it the countries which are at the
present day inhabited.” And he further declares that “this event has been
sudden, instantaneous, without any gradation; and what is so clearly
demonstrated with respect to this last catastrophe is not less so with
reference to those which preceded it.”
The method followed by Lyell was the very reverse of that of Cuvier.
Instead of assuming hastily that modern causes were totally inadequate, and
appealing constantly to purely imaginary and often inconceivable
catastrophes, Lyell investigated these causes with painstaking accuracy,
applying the tests of survey and time measurement, so as in many cases to
prove that, given moderately long periods of time—not a few thousands
only, but hundreds of thousands of years—they were fully adequate to
explain the phenomena. He also showed that the imaginary causes of
Cuvier would not explain the facts, for that everywhere in the crust of the
earth we found conclusive proofs of very slow continuous changes exactly

analogous to what now occur, never of great convulsions, except quite
locally, as we have them now. He showed that modern volcanoes had
poured out vast masses of melted rock during a single eruption, covering
areas as extensive as those which any ancient volcano could be proved to
have ejected in an equally short period; that strata were now in process of
formation comparable in extent and thickness with any ancient strata; that
organic remains are being preserved in them just as in the older rocks; that
the land is almost everywhere rising or sinking as of old; that valleys are
being excavated and plateaus or mountains upheaved; that earthquake
shocks are producing faults beneath the surface; that vegetation is still
preparing future coal beds; that limestones, clays, sandstones, metamorphic
and igneous rocks are all still being formed; and that, given time, and the
intermittent or continuous action of the causes we can now trace in
operation, and all the varied features of the earth’s surface, as well as all the
contortions and fractures which we discover in its crust, and every other
phenomenon supposed to necessitate catastrophes and cataclysms will be
again produced.
In the massive volumes of the later editions of the Principles of
Geology all these points are discussed and illustrated with such a wealth of
facts and such cogent yet cautious reasoning as have carried conviction to
all modern students. It affords us perhaps the very best proof yet given of
evolution in one department of the universe—that of the surface and the
crust of the earth we inhabit. Not only have all the chief modifications
during an almost unimaginable period of time been clearly depicted, but
they have in almost every case been shown to be the inevitable results of
real and comparatively well-known causes, such as we now see at work
around us.
The grand generalizations of Lyell have been strengthened since his
death by more complete investigations of certain phenomena and their
causes than were possible in his day; while the only objections to them
seem to be founded, to some extent, upon a misconception. He has been
termed a “Uniformitarian,” and it is alleged that it is unphilosophical to take
the limited range of causes we now see in action, as a measure of those
which have acted during all past geological time. But neither Lyell nor his
followers make any such assumption. They merely say, we do not find any
proof of greater or more violent causes in action in past times, and we do

find many indications that the great natural forces then in action—seas and
rivers, sun and cloud, rain and hail, frost and snow, as well as the very
texture and constituents of the older rocks, and the mode in which the
organisms of each age are preserved in them, must have been in their
general nature and magnitude very much as they are now. Other objections,
such as that the internal forces were greater when the earth was hotter, and
that tidal effects must have been more powerful when the moon was nearer
the earth, are altogether beside the question until we can obtain more
definite measures of past time than we now possess in reference to both
geological and cosmical phenomena. It may well be that the physical
changes above referred to have been so slow that they would have produced
no perceptibly increased effect at the epoch of the early stratified rocks.
Lyell’s doctrine is simply that of real against imaginary causes, and he only
denies catastrophes and more violent agencies in early times, because there
is no clear evidence of their actual existence, and also because known
causes are quite competent to explain all geological phenomena. It must be
remembered, too, that uniformitarians have never limited the natural forces
of past geological periods to the precise limits of which we have had
experience during the historical period. What they maintain is, that forces of
the same nature and of the same order of magnitude are adequate to have
brought about the evolution of the crust of the earth as we now find it.

ORGANIC EVOLUTION, ITS LAWS AND CAUSES

We now come to that branch of the subject which is the most important
and distinctive of our age, and which, in popular estimation, alone
constitutes evolution—the mode of origin of the innumerable species of
animal and plant life which now exist or have ever existed upon the earth.
The origin of the different forms of life has till quite recent times been
looked upon as an almost insoluble problem, although a few advanced
thinkers, even in the eighteenth century, perceived that it was probably the
result of some natural process of modification or evolution; but no force or
law had been set forth and established in any way adequate to produce it
until the publication of Darwin’s Origin of Species, in 1859. In the later
editions of that work, Darwin has given a historical sketch of the progress

of opinion on the subject. I shall, therefore, now only notice a few great
writers which he has not referred to.
We have seen what an impossible and even ludicrous explanation had
to be given by Lucretius; and from his day down to the middle of the
eighteenth century no advance had been made. Either the problem was not
referred to at all, or the theological doctrine of a special creation was held to
be the only possible one. But in the middle of the eighteenth century the
great French naturalist, Buffon, published his very important work, Histoire
Naturelle, in fifteen volumes (1749–1767), in which, besides describing the
characters and habits of all the animals then known, he introduced much
philosophical and speculative thought, which would probably have been
carried much further had he not felt obliged to conform to the religious
prejudices of the age. We are indebted to Mr. Samuel Butler for having
brought together all the important passages of Buffon’s voluminous and
now little-read works bearing upon the question of evolution, and it is from
his volume that I quote.
Buffon lays stress on the great resemblance of all mammalia in internal
structure, showing that the most unlike creatures may be really alike
structurally. He says: “The horse, for example—what can at first sight seem
more unlike mankind? Yet when we compare man and horse, point by point
and detail by detail, our wonder is excited rather by the resemblances than
by the differences between them.” He then shows that all the parts of the
skeleton agree, and that it is only in proportions, the increase of some bones
and the suppression of others, that they differ, adding: “If we regard the
matter thus, not only the ass and the horse, but even man himself, the apes,
etc., might be regarded as forming members of one and the same family.”
Then, after a few more illustrations, he remarks: “If we once admit that
there are families of plants and animals, so that the ass may be of the family
of the horse, and that the one may only differ from the other by
degeneration from a common ancestor, we might be driven to admit that the
ape is of the family of man, that he is but a degenerate man, and that he and
man have had a common ancestor.... If it were once shown that we had right
grounds for establishing these families, if the point were once gained that
among plants and animals there have been even a single species which had
been produced in the course of direct descent from another species, then
there is no further limit to be set to the power of nature, and we should not

be wrong in supposing that with sufficient time she could have evolved all
other organized forms from one primordial type.”
This indicates clearly enough his own opinion, but to save himself from
the ecclesiastical authorities he at once adds this saving clause: “But no! It
is certain, from revelation, that all animals have alike been favored with the
grace of an act of direct creation, and that the first pair of every species
issued full formed from the hands of the Creator.”
Such examples of disarming religious prejudice are frequent, but he
continually recurs to statements as to mutability which neutralize them.
Here, for example, is a broad claim for nature as opposed to creation. He
has been showing how variable are many animals, and how changes of
food, climate, and general surroundings influence both their forms and their
habits; and then he exclaims:
“What cannot nature effect with such means at her disposal? She can
do all except either create matter or destroy it. These two extremes of power
the Deity has reserved for Himself only; creation and destruction are the
action of His omnipotence. To alter and undo, to develop and renew—these
are powers which He has handed over to the charge of nature.”
Here we have a claim for the power of nature in the modification of
species which fully comes up to the requirements of the most advanced
evolutionist. It is remarkable, too, how clearly he perceived the great factors
so important for the evolution of organisms, rapid multiplication, great
variability, and the struggle for existence. Thus he remarks: “It may be said
that the movement of nature turns upon two immovable pivots—one, the
illimitable fecundity which she has given to all species; the other, the
innumerable difficulties which reduce the results of that fecundity and leave
throughout time nearly the same quantity of individuals in every species.”
Here the term “difficulties” corresponds to the “positive checks” of
Malthus, and to the “struggle for existence” of Darwin; and he again and
again refers to variability—as when he says: “Hence, when by some
chance, common enough with nature, a variation or special feature makes
its appearance, man has tried to perpetuate it by uniting together the
individuals in which it has appeared.”
As Buffon thus clearly understood artificial selection, thoroughly
appreciated the rapid increase of all organisms, and equally well saw that

their inordinate increase was wholly neutralized through such destructive
agencies as hunger, disease, and enemies, and as, at the same time, he had
such unbounded faith in the power of nature to modify animal and
vegetable forms, we feel assured that this great writer and original thinker
only needed freedom to pursue this train of thought a little further and he
would certainly have anticipated Darwin’s great discovery of natural
selection by a whole century. Even as it is we must class him as one of the
great pioneers of organic evolution.
The next distinct step towards a theory of organic evolution was made
by the poet Goethe at the very end of the eighteenth century, in his views of
the metamorphosis of plants. He pointed out the successive modifications of
the leaf which produced all the other essential parts of the higher plants—
the simple cotyledons or seed leaves became modified into the variously
formed leaves of the fully grown plants; these again were successively
modified into the calyx, corolla, stamens, and ovary of the flower. He
supposed this to be due to the increased refinement of the sap under the
influence of light and air, and to indicate the steps by which the various
parts of the flower had been developed. It was, therefore, a theory of
evolution; but it was very unsatisfactory, inasmuch as it in no way
accounted for the wonderful variety of the floral organs, or indicated any
purpose served by the most prominent and conspicuous part of the flower,
the highly colored and often strangely formed corolla. It was also erroneous
in supposing that the corolla was a modified calyx, whereas it is now
known to be a modification of the stamens.
Next came the great work of Lamarck in the first decade of the
nineteenth century, in which he proposed a general system of evolution of
the whole animal world. Hence he may be termed the first systematic
evolutionist. His system has been rather fully described by Lyell, who, in
his Principles of Geology, devotes a whole chapter to a summary of his
doctrines; while Mr. Butler gives copious quotations in three chapters of his
Evolution Old and New; and any one who is not acquainted with the
original work of Lamarck should read these two authors in order to
understand how wide was his knowledge, how ingenious his explanations,
and in how many important points he anticipated the views both of Lyell
and Darwin. But he was half a century in advance of his age, and his only
alleged causes of modification—changed conditions, use and disuse, habit

and effort—were wholly insufficient to account for the vast range of the
phenomena presented by the innumerable minute adaptations of living
organisms to their conditions of life. He even imputed all the modifications
of domestic animals to the changed conditions of food and habits to which
they have been subjected by man, making no reference to the use of
selection by breeders, in this respect falling short of his great predecessor,
Buffon.
The general laws which Lamarck deduces from his elaborate study of
nature are these:
“Firstly. That in every animal which has not passed its limit of
development, the more frequent and sustained employment of any organ
develops and aggrandizes it, giving it a power proportionate to the duration
of its employment, while the same organ, in default of constant use,
becomes insensibly weakened and deteriorated, decreasing imperceptibly in
power until it finally disappears.
“Secondly. That these gains or losses of organic development, due to
use or disuse, are transmitted to offspring, provided they have been
common to both sexes, or to the animals from which the offspring have
descended.”
The whole force of this argument depends upon the second clause—the
inheritance of those individual modifications due to use and disuse. But no
direct evidence of this has ever been found, while there is a good deal of
evidence showing that it does not occur. Again, there are many structures
which cannot have been produced by use, such, for example, as the feathers
of the peacock’s train, the poison in the serpent’s fangs, the hard shells of
nuts, the prickly covering of many fruits, the varied armor of the turtle,
porcupine, crocodile, and many others. For these reasons Lamarck’s views
gained few converts; and although some of his arguments have been upheld
in recent years, the fatal objections to his general principle as a means of
explaining the evolution of organic forms has never been overcome.
Between the periods of Lamarck and Darwin many advances were
made which clearly pointed to a general law of evolution in nature. Such
were Sir William Grove’s lectures on the “Correlation of the Physical
Forces,” in 1842; Helmholtz on the “Conservation of Energy,” in 1847; and
Herbert Spencer’s essay on “The Development Hypothesis,” in 1852. This

latter work was a complete and almost unanswerable argument for a natural
process of continuous evolution of the whole visible universe, including
organic nature, man, and social phenomena. It is further extended in the
later editions of the author’s First Principles, which, as a coherent
exposition of philosophy, co-ordinating and explaining all human
knowledge of the universe into one great system of evolution everywhere
conforming to the same general principles, must be held to be one of the
greatest intellectual achievements of the nineteenth century. It left, however,
the exact method of evolution of organisms untouched, and thus failed to
account for those complex adaptations and appearances of design in the
various species of animals and plants which have always been the
stronghold of those who advocated special creation. This difficulty was met
by Darwin’s theory of The Origin of Species by Means of Natural Selection,
published in 1859, and the series of works that succeeded it; and to a brief
sketch of this theory the remainder of our space must be devoted.

THE THEORY OF “NATURAL SELECTION”

Although, as we have seen, a succession of great writers and thinkers
had for more than half a century shown the necessity for some process of
evolution as the only rational or intelligible mode of origin of existing
species of animals and plants, as well as of the whole physical universe, yet
these views were by no means generally accepted by the educated classes,
while few bodies of students were less influenced by them than zoologists
and botanists, generally known as naturalists.
Now, Darwin wrote especially for these classes, and no one knew better
than he did their great prejudice on this matter. Not only had such men as
Sir Charles Lyell and Sir John Herschel expressed themselves strongly
against all theories of the transmutation of species, but the universal
contempt and indignation of naturalists as well as theologians against The
Vestiges of Creation, published anonymously a few years earlier, and giving
a most temperate and even religious exposition of the general arguments for
the universality of evolution, showed what any one might expect who
advocated and attempted to demonstrate a similar theory. This accounts for
Darwin writing to Sir Joseph Hooker, in 1844, of his being “almost

convinced that species are not (it is like confessing a murder) immutable,”
and again, in 1845, to the Rev. L. Blomefield, that he now saw the way in
which new varieties become exquisitely adapted to the external conditions
of life and to other surrounding beings, and he adds: “I am a bold man to
lay myself open to being thought a complete fool, and a most deliberate
one.” It is only by a consideration of the frame of mind of even advanced
thinkers at the time Darwin was preparing his work, and remembering how
small was the effect which had been produced by Buffon, Goethe, Lamarck,
the author of Vestiges of Creation, and the earlier writings of Herbert
Spencer, that we can adequately realize the marvellous work that he
accomplished. Let us now briefly consider the essential nature of this new
theory, which in a few brief years became the established belief of the great
majority of the students of nature, and which also gave a new interest in
nature to the whole thinking world.
The theory of natural selection is founded upon a few groups of
thoroughly ascertained and universally admitted facts, with the direct and
necessary results of those facts.
The first group of facts consists of the great powers of increase of all
organisms and the circumstance that, notwithstanding this great yearly
increase, the actual population of each species remains stationary, there
being no permanent increase. Now, these two facts were recognized by
Buffon, but though, of course, known to all subsequent writers, were fully
appreciated or thought out to their logical results by none of them.
Lamarck, so far as I can ascertain, took no notice of them whatever. Darwin
has given illustrations of these facts in Chapter IV. of the Origin of Species,
and I have added others in the second chapter of my Darwinism. That the
population of each species remains stationary, with, of course, considerable
fluctuations, is both a matter of observation and of reasoning. The powers
of increase of all creatures are so great that if there is in any country room
and food for a larger number of any species they will be produced in a year
or two. It is impossible, therefore, to believe that, in a state of nature, where
all kinds of animals and plants have lived together as they best could for
thousands of years, there can be any important difference in their numbers
from year to year or from century to century.
Now, it is as a consequence of these two indisputable facts that the
struggle for existence necessarily results. For if every year each pair of

animals or each plant produces only ten young animals or plants, and this is
very far below the average, and if the adult life of these is taken at ten
years, again below the average of the higher plants and animals, then,
unless some of the parents die, the whole of the offspring must die off every
year; or, in other words, only as many young can survive as are necessary to
replace the old ones that die. Hence the deaths must always (on the average
and in the long run) equal the births. This terrible yearly destruction is an
absolutely certain fact, as well as an inevitable result of the two preceding
facts, and it is said to be due to the struggle for existence. This struggle is
manifold in its nature. Individuals of the same species struggle together for
food, for light, for moisture; they struggle also against other species having
the same wants; they struggle against every kind of enemy, from parasitic
worms and insects up to carnivorous animals; and there is a continual
struggle with the forces of nature—frosts, rains, droughts, floods, and
tempests.
These varied causes of destruction may be seen constantly at work by
any one who looks for them. They act from the moment of birth, being
more especially destructive to the young; and, as only one in ten or fifty or
a thousand (according to the rate of increase of the particular species) can
possibly come to the full breeding age, we feel compelled to ask ourselves:
What determines the nine or the forty-nine or the nine hundred and ninety-
nine, as the case may be, which die, and the one which survives? Darwin
calls this process of extermination one of “natural selection”—that is, by
this process nature weeds out the weak, the unhealthy, the unadapted, the
imperfect in any way. Of course, what may be called chance or accident
produces many deaths of individuals otherwise well fitted to live, but if we
think of the process going on day by day and year by year till only one in a
hundred of those born in a given area are left alive, it is impossible to
suppose that the one which has passed through all the dangers and risks
which have been fatal to, say, his ninety-nine relations was not, in all the
faculties and qualities essential to the continuance of the race, decidedly
better organized than the bulk of those which succumbed. Herbert Spencer
calls the process the “survival of the fittest,” and though the term may not
be strictly accurate in the case of any one species in any one year, yet when
we consider that the struggle is going on every year, during the whole
duration of each species, we cannot doubt that, on the whole, and in the
long run, those which survive are among the fittest. The struggle is so

severe, so incessant, that the smallest defect in any sense organ, any
physical weakness, any imperfection in constitution, will almost certainly,
at one time or another, be fatal.
This continual weeding out of the less fit, in every generation, and with
exceptional severity in recurring adverse seasons, will produce two distinct
effects, which require to be clearly distinguished. The first is the
preservation of each species in the highest state of adaptation to the
conditions of its existence; and, therefore, so long as these conditions
remained unchanged, the effect of natural selection is to keep each well-
adapted species also unchanged. The second effect is produced whenever
the conditions vary, when, taking advantage of the variations continually
occurring in all well-adapted and therefore populous species, the same
process will slowly but surely bring about complete adaptation to the new
conditions. And here another fact—the normal variability of all populous or
dominant species, which is seldom realized except by those who have
largely and minutely compared the individuals of many species in a state of
nature—comes into play. There are some writers who admit all the
preceding facts and reasoning, so far as the action of natural selection in
weeding out the unfit and thus keeping every species in the highest state of
efficiency is concerned, but who deny that it can modify them in such a way
as to adapt them to new conditions, because they allege that “the right
variations will not always occur at the right time.” This seems a strong and
real objection to many of their readers, but to those who have studied the
variability of species in nature, it is a mere verbal difficulty dependent on
ignorance of the actual facts. A brief statement of the facts must therefore
be given.
Of late years, and chiefly since Darwin’s works were written, the
variability of animals and plants in a state of nature has been carefully
studied, by actual comparison and measurement of scores, hundreds, and
even thousands of individuals of many common, that is, abundant and
widely distributed species; and it is found that in almost every case they
vary greatly, and, what is still more important, that every organ and every
appendage varies independently and to a large amount. Some of the best
known of these facts of variation are adduced in my Darwinism, and are
illustrated by numerous diagrams, and much more extensive series have
since been examined, always with the same general result. By large

variability is meant a variation of from ten to twenty-five per cent. on each
side of the mean size, this amount of variation occurring in at least five or
ten per cent. of the whole number of individuals, and in every organ or part
as yet examined, external or internal.
Now, as the weeding-out process is so severe, only from one in ten to
one in a hundred of those born surviving to produce young, the above
proportion of variations affords ample scope for the selection of any
variation needed in order to modify the species so as to bring it into
harmony with new or changing conditions. And this will be the more easy
and certain if we consider how slowly land-surfaces and climates undergo
permanent changes; and these are certainly the kind of changes that initiate
and compel alterations, first, perhaps, in the distribution, and afterwards in
the structure and habits of species. It follows, therefore, as an absolutely
necessary conclusion from the facts, if natural selection can and does keep
each continually varying species in close adaptation to an unchanging
environment, that it preserves the fixity of its mean or average condition,
and almost every objector admits this. Then, given a slowly changing
environment, the same power must inevitably bring about whatever
corresponding change is needed for the well-being and permanent survival
of the various species which are subjected to those changed conditions.
I shall not add here a further consideration of the objections and
difficulties alleged by critics of the theory. All of these have, I believe, been
fully answered either by Darwin or myself, many of the most recent having
been discussed in review articles. Suffice it to say here that this theory of
natural selection—meaning the elimination of the least fit, and therefore the
ultimate “survival of the fittest”—has furnished a rational and precise
explanation of the means of adaptation of all existing organisms to their
conditions, and therefore of their transformation from the series of distinct
but allied species which occupied the earth at some preceding epoch. In this
sense it has actually demonstrated the “origin of species,” and, by carrying
back this process step by step into earlier and earlier geological times, we
are able mentally to follow out the evolution of all forms of life from one or
a few primordial forms. Natural selection has thus supplied that motive
power of change and adaptation that was wanting in all earlier attempts at
explanation, and this has led to its very general acceptance both by
naturalists and by the great majority of thinkers and men of science.

The brief sketch now given of the progress of human thought on the
questions of the fact and the mode of the evolution of the material universe
indicates how great has been the progress during the nineteenth as
compared with all preceding centuries.
Although the philosophical writers of classical times obtained a few
glimpses of the action of law in nature regulating its successive changes,
nothing satisfactory could be effected till the actual facts had been better
ascertained by the whole body of workers who, during the last five
centuries, have penetrated ever more and more deeply into nature’s
mysteries and laws. By their labors we became possessed of such a body of
carefully observed facts that, towards the end of the eighteenth century,
such thinkers as Laplace and Hutton were enabled to give us the first
rudiments of theories of evolution as applied to the solar system and the
earth’s crust, both of which have been greatly developed and rendered more
secure during the century just passed away.
In like manner Buffon and Goethe may be said to have started the idea
of organic evolution, more systematically treated a little later by Lamarck,
but still without any discovery of laws adequate to produce the results we
see everywhere in nature. The subject then languished, till, after twenty
years of observation and research, Charles Darwin produced a work which
at once satisfied many thinkers that the long-desired clew had been
discovered. Its acceptance by almost the whole scientific world soon
followed: it threw new light on almost every branch of research, and it will
probably take its place, in the opinion of future generations, as the crowning
achievement of the nineteenth century.

Alfred Russel Wallace.

CHEMISTRY

T hethought.
progress of the science of chemistry forms one phase of the progress of human
While at first mankind was contented to observe certain phenomena, and to
utilize them for industrial purposes, if they were found suitable, “philosophers,” as the
thinking portion of our race loved to call themselves, have always attempted to assign some
explanation for observed facts, and to group them into similars and dissimilars. It was for
long imagined, following the doctrines of the Greeks and of their predecessors, that all
matter consisted of four elements or principles, names which survive to this day in popular
language. These were “fire,” “air,” “water,” and “earth.” It was not until the seventeenth
century that Boyle in his Sceptical Chymist (1661) laid the foundations of the modern
science, by pointing out that it was impossible to explain the existence of the fairly
numerous chemical substances known in his day, or the changes which they can be made to
undergo, by means of the ancient Greek hypotheses regarding the constitution of matter. He
laid down the definition of the modern meaning of the word “element”; he declined to
accept the current view that the properties of matter could be modified by its assimilating the
qualities of fire, air, earth, or water, and he defined an element as the constituent of a
compound body. The first problem, then, to be solved, was to determine which of the
numerous forms of matter were to be regarded as elementary, and which are compound, or
composed of two or more elements in a state of combination; and to produce such
compounds by causing the appropriate elements to unite with each other.

One of the first objects to excite curiosity and interest was the air which surrounds us,
and in which we live and move and have our being. It was, however, endowed with a semi-
spiritual and scarcely corporeal nature in the ideas of our ancestors, for it does not affect the
senses of sight, smell, or taste, and though it can be felt, yet it eludes our grasp. The word
“gas,” moreover, was not invented until Van Helmont devised it to designate various kinds
of “airs” which he had observed. The important part which gases play in the constitution of
many chemical compounds was accordingly overlooked; and, indeed, it appeared to be
almost as striking a feat of necromancy to produce a quantity of a gas of great volume from
a small pinch of solid powder as for a “Jinn” of enormous stature but of delicate texture to
issue from a brass pot, as related in the Arabian Nights Entertainments. Gradually, however,
it came to be recognized, not merely that gases have corporeal existence, but that they even
possess weight. This, though foreshadowed by Torricelli, Jean Rey, and others, was first
clearly proved by Black, professor of chemistry in Edinburgh, in 1752, through his masterly
researches, as carbonic acid.

The ignorance of the material nature of gases and of their weight lies at the bottom of
the “Phlogistic Theory,” a theory devised by Stahl about the year 1690, to account for the
phenomena of combustion and respiration and the recovery or “reduction” of metals from
their “earths” by heating with charcoal or allied bodies. According to this inverted theory, a
substance capable of burning was imagined to contain more or less phlogiston, a principle
which it parted with on burning, leaving an earth deprived of phlogiston, or
“dephlogisticated,” behind if a metal. This earth, when heated with substances rich in
phlogiston, such as coal, wood, flour, and similar bodies, recovered the phlogiston, which it
had lost on burning, and, with the added phlogiston, its metallic character. Other substances,
such as phosphorus and sulphur, gave solids or acid liquids, to which phlogiston was not so
easy to add; but even they could be rephlogisticated. On this hypothesis, it was the earths,
and such acid liquids as sulphuric or phosphoric acids, which were the elements; the metals
and sulphur and phosphorus were their compounds with phlogiston.
The discovery of oxygen by Priestley and by Scheele in 1774, and the explanation of its
functions by Lavoisier during the following ten years, gave their true meaning to these
phenomena. It was then recognized that combustion was union with oxygen; that an “earth”
or “calx” was to be regarded as the compound of a metal with oxygen; that when a metal
becomes tarnished, and converted into such an earthy powder, it is being oxidized; that this
oxide, on ignition with charcoal or carbon, or with compounds such as coal, flour, or wood,
of which carbon is a constituent, gives up its oxygen to the carbon, forming an oxide of
carbon, carbonic oxide on the one hand, or carbonic “acid” on the other, while the metal is
reproduced in its “reguline” or metallic condition, and that the true elements are metals,
carbon, sulphur, phosphorus, and similar bodies, and not the products of their oxidation.
The discovery that air is in the main a mixture of nitrogen, an inert gas, and oxygen, an
active one, together with a small proportion of carbonic “acid” (or, as it is now termed,
anhydride)—a discovery perfected by Rutherford, Black, and Cavendish—and that water is
a compound with oxygen of hydrogen, previously known as inflammable air, by Cavendish
and by Watt, finally overthrew the theory of phlogiston; but at the beginning of this century
it still lingered on, and was defended by Priestley until his death in 1804. Such, in brief, was
the condition of chemical thought in the year 1800. Scheele had died in 1786, at the early
age of forty-four; Lavoisier was one of the victims of the French Revolution, having been
guillotined in 1794; Cavendish had ceased to work at chemical problems, and was devoting
his extraordinary abilities to physical problems of the highest importance, while living the
life of an eccentric recluse, and Priestley, driven by religious persecution from England to
the more tolerant shores of America, was enjoying a peaceful old age, enlivened by
occasional incursions into the region of sectarian controversy.
The first striking discovery of our century was that of the compound nature of the
alkalies and of the alkaline earths. This discovery was made by Humphry Davy. Born in
Cornwall in 1778, he began the study of chemistry, self-taught, in 1796; and in 1799 he
became director of the “Pneumatic Institution,” an undertaking founded by Dr. Beddoes, at
Bristol, for the purpose of experiments on the curative effects of gases in general. Here he at
once made his mark by the discovery of the remarkable properties of “laughing gas,” or
nitrous oxide. At the same time he constructed a galvanic battery, and began to perform
experiments with it in attempting to decompose chemical compounds by its means. In 1801

Davy was appointed professor of chemistry at the Royal Institution, a society or club which
had been founded a few years previously by Benjamin Thompson, Count Rumford, for the
purpose of instructing and amusing its members with recent discoveries in chemistry and
natural philosophy. In 1807 Davy applied his galvanic battery to the decomposition of damp
caustic potash and soda, using platinum poles. He was rewarded by seeing globules of
metal, resembling mercury in appearance, at the negative pole; and he subsequently proved
that these globules, when burned, reproduced the alkali from which they had been derived.
They also combined with “oxymuriatic acid,” as chlorine (discovered by Scheele) was then
termed, forming ordinary salt, if sodium be employed, and the analogous salt, “muriate of
potash,” if the allied metal, potassium, were subjected to combustion. By using mercury as
the negative pole, and passing a current through a strong solution of the chloride of calcium,
strontium, or barium, Davy succeeded in procuring mixtures with mercury or “amalgams” of
their metals, to which he gave the names calcium, strontium, and barium. Distillation
removed most of the mercury, and the metal was left behind in a state of comparative purity.
The alkali metals, potassium and sodium, were found to attack glass, liberating “the basis of
the silex,” to which the name silicon has since been given.
Thus nearly the last of the “earths” had been decomposed. It was proved that not merely
were the “calces” of iron, copper, lead, and other well-known metals compounds of the
respective metals with oxygen, but Davy showed that lime, and its allies, strontia and baryta,
and even silica or flint, were to be regarded as oxides of elements of metallic appearance. To
complete our review of this part of the subject, suffice it to say that aluminum, a metal now
produced on an industrial scale, was prepared for the first time in 1827 by Wöhler, professor
of chemistry at Göttingen, by the action of potassium on its chloride, and alumina, the earthy
basis of clay, was shown to be the oxide of the metal aluminum. Indeed, the preparation of
this metal in quantity is now carried out at Schoffhausen-on-the-Rhine and at the Falls of
Foyers, in Scotland, by electrolysis of the oxide dissolved in melted cryolite, a mineral
consisting of the fluorides of sodium and aluminum, by a method differing only in scale
from that by means of which Davy isolated sodium and potassium in 1806.
To Davy, too, belongs the merit of having dethroned oxygen from its central position
among the elements. Lavoisier gave to this important gas the name “oxygen,” because he
imagined it to be the constituent of all acids. He renamed the common compounds of
oxygen in such a manner that the term oxygen was not even represented in the name—only
inferred. Thus a “nitrate” is a compound of an oxide of nitrogen and an oxide of a metal; a
“sulphate,” of the oxide of a metal with one of the oxides of sulphur, and so on. Davy, by
discovering the elementary nature of chlorine, showed, first, that it is not an oxide of
hydrochloric acid (or muriatic acid as it was then called); and, second, that the latter acid is
the compound of the element chlorine with hydrogen. This he did by passing chlorine over
white-hot carbon—a substance eminently suited to deprive oxy-compounds of their oxygen
—and proving that no oxide of carbon is thereby produced; by acting on certain chlorides,
such as those of tin or phosphorus with ammonia, and showing that no oxide of tin or
phosphorus is formed; and, lastly, by decomposing “muriatic acid gas” (gaseous hydrogen
chloride) with sodium, and showing that the only product besides common salt is hydrogen.
Instead, therefore, of the former theory that a chloride was a compound of the unknown
basis of oxymuriatic acid with oxygen and the oxide of a metal, he introduced the simpler

and correct view that a chloride is merely a compound of the element chlorine with a metal.
In 1813 he established the similar nature of fluorine, pointing out that on the analogy of the
chlorides it was a fair deduction that the fluorides are compounds of an undiscovered
element, fluorine, with metals; and that hydrofluoric acid is the true analogue of
hydrochloric acid. The truth of this forecast has been established of recent years by Henri
Moissan, who isolated gaseous fluorine by subjecting a mixture of hydrofluoric acid and
hydrogen potassium fluoride contained in a platinum U tube to the action of a powerful
electric current. He has recently found that the tube may be equally well constructed of
copper; and this may soon lead to the industrial application of the process. The difficulty of
isolating fluorine is due to its extraordinary chemical energy; for there are few substances,
elementary or compound, which resist the action of this pale yellow, suffocating gas. In 1811
iodine, separated by Courtois from the ashes of sea-plants, was shown by Davy to be an
element analogous to chlorine. Gay-Lussac subsequently investigated it and prepared many
of its compounds; and in 1826 the last of these elements, bromine, was discovered in the
mother-liquor of sea-salt by Balard. The elements of this group have been termed
“halogens,” or “salt producers.”
While Davy was pouring his researches into the astonished ears of the scientific and
dilettante world, John Dalton, a Manchester school-master, conceived a theory that has
proved of the utmost service to the science of chemistry, and which bids fair to outlast our
day. It had been noticed by Wenzel, by Richter, by Wollaston, and by Cavendish, towards
the end of the last century, that the same compounds contain the same constituents in the
same proportions, or, as the phrase runs, “possess constant composition.” Wollaston, indeed,
had gone one step farther, and had shown that when the vegetable acid, oxalic acid, is
combined with potash, it forms two compounds, in one of which the acid is contained in
twice as great an amount relatively to the potash as in the other. The names monoxalate and
binoxalate of potash were applied to these compounds, to indicate the respective proportions
of the ingredients. Dalton conceived the happy idea that by applying the ancient Greek
conception of atoms to such facts the relative weights of the atoms could be determined.
Illustrating his views with the two compounds of carbon with hydrogen, marsh gas and
olefiant gas, and with the two acids of carbon, carbonic oxide, carbonic “acid,” he regarded
the former as a compound of one atom of carbon and one of hydrogen, and the second as a
compound of one atom of carbon and two of hydrogen, and similarly for the two oxides of
carbon. Knowing the relative weights in which these elements enter into combination, we
can deduce the relative weights of the atoms. Placing the relative weight of an atom of
hydrogen equal to unity, we have:
Marsh Olefiant Carbonic Carbonic
Gas Gas Oxide Acid
Carbon 6 6 Carbon 5 6
Hydrogen 1 2 Oxygen 8 16

Thus the first compound, marsh gas, was regarded by Dalton as composed of an atom of
carbon in union with an atom of hydrogen; or, to reproduce his symbols, as ; while the
second, olefiant gas, on this hypothesis, was a compound of two atoms of hydrogen with one
of carbon, or . Similarly the symbols , and were given to the two

compounds of carbon with oxygen. So water was assigned the symbol , for Dalton
imagined it to be a compound of one atom of hydrogen with one of oxygen. Compounds
containing only two atoms were termed by him “binary”; those containing three, “ternary”;
four, “quaternary,” and so on. The weight of an atom of oxygen was eight times that of an
atom of hydrogen; while that of an atom of carbon was six times as great as the unit. By
assigning symbols to the elements, consisting of the initial letters of their names, or of the
first two letters, formulas were developed, indicating the composition of the compound, the
atomic weights of the elements being assured. Thus, NaO signified a compound of an atom
of sodium (natrium), weighing twenty-three times as much as a similar atom of hydrogen,
with an atom of oxygen, possessing eight times the weight of an atom of hydrogen.
Therefore, thirty-one pounds of soda should consist of twenty-three pounds of sodium in
combination with eight pounds of oxygen, for, according to Dalton, each smallest particle of
soda contains an atom of each element, and the proportion is not changed, however many
particles be considered.
It has been pointed out by Judge Stallo, of Philadelphia, in his Concepts of Physics, that
such a hypothesis as that of Dalton is no explanation; that a fact of nature, as, for example,
the fact of simple and multiple proportions, is not explained by being minified. Allowing the
general truth of this statement, it is, nevertheless, undoubted that chemistry owes much to
Dalton’s hypothesis—a lucky guess at first, it represents one of the fundamental truths of
nature, although its form must be somewhat modified from that in which Dalton conceived
it. Dalton’s work was first expounded by Thomas Thomson, professor at Glasgow, in his
System of Chemistry, published in 1805; and subsequently in Dalton’s own New System of
Chemical Philosophy, the three volumes of which were published in 1808, in 1810, and in
1827.
The determination of these “Constants of Nature” was at once followed out by many
chemists, Thomson among the first. But chief among the chemists who have pursued this
branch of work was Jacob Berzelius, a Swede, who devoted his long life (1779–1848) to the
manufacture of compounds, and to the determination of their composition, or, as it is still
termed, the determination of the “atomic weights”—more correctly, “equivalents”—of the
elements of which they are composed. It is to him that we owe most of our analytical
methods, for, prior to his time, there were few, if any, accurate analyses. Although Lavoisier
had devised a method for the analysis of compounds of carbon, viz., by burning the organic
compounds in an atmosphere of oxygen contained in a bell-jar over mercury, and measuring
the volume of carbon dioxide produced, as well as that of the residual oxygen, Berzelius
achieved the same results more accurately and more expeditiously by heating the substance,
mixed with chlorate of potassium and sodium chloride, and then estimating the hydrogen as
well as the carbon; this process was afterwards perfected by Liebig. Berzelius, however, was
able to show that compounds of carbon, like those of other elements, were instances of
combination in constant and in multiple proportions.
In 1815 two papers were published in the Annals of Philosophy by Dr. Prout, which
have had much influence on the progress of chemistry. They dealt with the figures which
were being obtained by Thomson, Berzelius, and others, at that time supposed to represent
the “atomic weights” of the elements. Prout’s hypothesis, based on only a few numbers, was
that the atomic weights of all elements were multiples of that of hydrogen, taken as unity.

There was much dispute regarding this assertion at the time, but as it was contradicted by
Berzelius’s numbers, the balance of opinion was against it. But about the year 1840 Dumas
discovered an error in the number (12.12) given by Berzelius as the atomic weight of
carbon; and with his collaborator, Stas, undertook the redetermination of the atomic weights
of the commoner elements—for example, carbon, oxygen, chlorine, and calcium. This line
of research was subsequently pursued alone by Stas, whose name will always be
remembered for the precision and accuracy of his experiments. At first Dumas and Stas
inclined to the view that Prout’s hypothesis was a just one, but it was completely disproved
by Stas’s subsequent work, as well as by that of numerous other observers. It is,
nevertheless, curious that a much larger proportion of the atomic weights approximate to
whole numbers than would be foretold by the doctrine of chances, and perhaps the last has
not been heard of Prout’s hypothesis, although in its original crude form it is no longer
worthy of credence.
One of the most noteworthy of the discoveries of the century was made by Gay-Lussac
(1778–1850) in the year 1808. In conjunction with Alexander von Humboldt, Gay-Lussac
had rediscovered about three years before what had previously been established by
Cavendish—namely, that, as nearly as possible, two volumes of hydrogen combine with one
volume of oxygen to form water, the gases having been measured at the same temperature
and pressure. Humboldt suggested to Gay-Lussac that it would be well to investigate
whether similar simple relations exist between the volumes of other gaseous substances
when they combine with each other. This turned out to be the case; it appeared that almost
exactly two volumes of carbonic oxide unite with one volume of oxygen to form carbon
dioxide; that equal volumes of chlorine and hydrogen unite to form hydrochloric acid gas;
that two volumes of ammonia gas consist of three volumes of hydrogen in union with one
volume of nitrogen, and so on. From such facts, Gay-Lussac was led to make the statement
that: The weights of equal volumes of both simple and compound gases, and therefore their
densities, are proportional to their empirically found combining weights, or to rational
multiples of the latter. Gay-Lussac recognized this discovery of his to be a support for the
atomic theory; but it did not accord with many of the then received atomic weights. The
assumption that equal volumes of gases contain equal numbers of particles, or, as they were
termed by him, molécules intégrantes, was made in 1811 by Avogadro, professor of physics
at Turin (1776–1856). This theory, which has proved of the utmost importance to the
sciences both of physics and of chemistry, had no doubt occurred to Gay-Lussac, and had
been rejected by him for the following reasons: A certain volume of hydrogen, say one cubic
inch, may be supposed to contain an equal number of particles (atoms) as an equal volume
of chlorine. Now these two gases unite in equal volumes. The deduction appears so far quite
legitimate that one atom of hydrogen has combined with one atom of chlorine. But the
resulting gas occupies two cubic inches, and must therefore contain the same number of
particles of hydrogen chloride, the compound of the two elements, as one cubic inch
originally contained of hydrogen, or of chlorine. Thus we have two cubic inches containing,
of uncombined gases, twice as many particles as is contained in that volume, after
combination. Avogadro’s hypothesis solved the difficulty. By premising two different orders
of particles, now termed atoms and molecules, the solution was plain. According to him,
each particle, or molecule, of hydrogen is a complex, and contains two atoms; the same is
the case with chlorine. When these gases combine, or rather react, to form hydrogen

chloride, the phenomenon is one of a change of partners; the molecule, the double atom, of
hydrogen splits; the same is the case with the molecule of chlorine; and each liberated atom
of hydrogen unites with a liberated atom of chlorine, forming a compound, hydrogen
chloride, which equally consists of a molecule, or double atom. Thus two cubic inches of
hydrogen chloride consist of a definite number of molecules, equal in number to those
contained in a cubic inch of hydrogen, plus those contained in a cubic inch of chlorine. The
case is precisely similar, if other compounds of gases be considered.
Berzelius was at first inclined to adopt this theory, and indeed went so far as to change
many of his atomic weights to make them fit it. But later he somewhat withdrew from his
position, for it appeared to him that it was hazardous to extend to liquids and solids a theory
which could be held only of gases. Avogadro’s suggestion, therefore, rested in abeyance
until the publication, in 1858, by Cannizzaro, now professor of chemistry in Rome, of an
essay in which all the arguments in favor of the hypothesis were collected and stated in a
masterly manner. It will be advisable to revert to this hypothesis at a later point, and to
consider other guides for the determination of atomic weights.
In 1819, Dulong (1785–1838), director of the Ecole Polytechnique at Paris, and Petit
(1791–1820), professor of physics there, made the discovery that equal amounts of heat are
required to raise equally the temperature of solid and liquid elements, provided quantities
are taken proportional to their atomic weights. Thus, to raise the temperature of 56 grammes
of iron through one degree requires approximately the same amount of heat as is required to
raise through one degree 32 grammes of sulphur, 63.5 grammes of copper, and so on; these
numbers representing the atomic weights of the elements named. In other words, equal
numbers of atoms have equal capacity for heat. The number of heat units, or calories (one
calory is the amount of heat required to raise the temperature of 1 gramme of water through
1° C.), which is necessary to raise the atomic weight expressed in grammes of any solid or
liquid element through 1° C. is approximately 6.2; it varies between 5.7 and 6.6 in actual
part. This affords a means of determining the true value of the atomic weight of an element,
as the following example will show: The analysis of the only compound of zinc and chlorine
shows that it contains 47.49 per cent. of zinc and 52.16 per cent. of chlorine. Now one grain
of hydrogen combines with 35.5 grains of chlorine to form 36.5 grains of hydrogen chloride;
and, as already remarked, one volume of hydrogen and one volume of chlorine combine,
forming two volumes of hydrogen chloride. Applying Avogadro’s hypothesis, one molecule
of hydrogen and one molecule of chlorine react to yield two molecules of hydrogen
chloride; and as each molecule is supposed to consist in this case of two atoms, hydrogen
chloride consists of one atom of each of its constituent elements. The amount of that
element, therefore, which combines with 35.5 grains of chlorine may give the numerical
value of the atomic weight of the element, if the compound contains one atom of each
element; in that case the formula of the above compound would be zinc, and the atomic
weight of zinc, 32.7; but if the formula is ZuCl3, the atomic weight of zinc would be 32.7 ×
2; if ZuCl3, 32.7 × 3, and so on. The specific heat of metallic zinc enables this question to be
solved. For it has been found, experimentally, to be about 0.095; and 6.2 ÷ 0.095 = 65.2, a
close approximation to 32.7 × 2 = 65.4. The conclusion is therefore drawn that zinc chloride
is composed of one atom of zinc in combination with two atoms of chlorine, that the atomic
weight of zinc is 65.4, and that the molecular weight of zinc chloride is 65.4 + (35.5 × 2) =

136.4. Inasmuch as the relative weight of a molecule of hydrogen is 2 (that of an atom being
1), zinc chloride in the gaseous state should be 136.4 ÷ 2 = 68.2 times that of hydrogen,
measured at the same temperature and pressure. This has been found, experimentally, to be
the case.
The methods of determining the vapor densities, or relative weights of vapors, are three
in number; the first method, due to Dumas (1827), consists in vaporizing the substance in
question in a bulb of glass or of porcelain, at a known temperature, closing the bulb while
still hot, and weighing it after it is cold. Knowing the capacity of the bulb, the weight of
hydrogen necessary to fill it at the desired temperature can be calculated, and the density of
the vapor thus arrived at. A second method was devised by Gay-Lussac and perfected by
A. W. Hofmann (1868); and a third, preferable for its simplicity and ease of execution, is
due to Victor Meyer (1881).
In 1858, as already remarked, Cannizzaro showed the connection between these known
facts, and for the first time attention was called to the true atomic weights, which were, up to
that time, confused with equivalents, or weights of elements required to replace one unit
weight of hydrogen. These were generally regarded as atomic weights by Dalton and his
contemporaries.
Some exceptions had been observed to the law of Dulong and Petit, viz., beryllium, or
glucinium, an element occurring in emeralds; boron, of which borax is a compound; silicon,
the component of quartz and flint, and carbon. It was found by Weber that at high
temperatures the specific heats of these elements are higher, and the atomic heats
approximate to the number of 6.2; but this behavior is not peculiar to these elements, for it
appears that the specific heat of all elements increases with rise of temperature.
A certain number of exceptions have also been noticed to the law of Gay-Lussac, which
may be formulated: the molecular weight of a compound in a gaseous state is twice its
density referred to hydrogen. Thus equal volumes of ammonia and hydrogen chloride unite
to form ammonium chloride. It was to be expected that the density should be half the
molecular weight, thus:

NH3 + HCl = NH4 Cl; and 53.5 ÷ 2 = 26.75 = density.
(14+3) (1+35.5) 53.5

But the density actually found is only half that number, viz., 13.37; and for long this and
similar cases were supposed to be exceptions to the law of Gay-Lussac, viz., that equal
volumes of gases at the same pressure expand equally for equal rise of temperature. In other
instances the gradual decrease in density with rise of temperature can be followed, as with
chloral hydrate, the products of which are chloral and water.
It was recognized by St. Claire Deville (1857) that the decrease in density of such
mixtures of gases was due, not to their being exceptions to Avogadro’s law, but to the
gradual decomposition of the compound body with rise of temperature. To this gradual
decomposition he gave the name dissociation. This conception has proved of the utmost
importance to the science, as will be seen in the sequel. To take the above instance of
ammonium chloride, its abnormal density is due to its dissociation into ammonia and

hydrogen chloride; and the gas which is obtained on raising its temperature consists, not of
gaseous ammonium chloride, but of a mixture of ammonia and hydrogen chloride, which, as
is easily seen, occupy, when separate, twice the volume that would be occupied by the
gaseous compound. Of recent years it has been shown by Brereton Baker that, if perfectly
free from moisture, ammonium chloride gasifies as such, and that its density in the state of
vapor is, in fact, 26.75.
The molecular complexity of gases has thus gradually become comprehended, and the
truth of Avogadro’s law has gained acceptance. And as a means of picturing the behavior of
gaseous molecules, the “Kinetic Theory of Gases” has been devised by Joule, Clausius,
Maxwell, Thomson (Lord Kelvin), and others. On the assumption that the pressure of a gas
on the walls of the vessel which contains it is due to the continued impacts of its molecules,
and that the temperature of a gas is represented by the product of the mass of the molecules,
or the square of their velocity, it has been possible to offer a mechanical explanation of
Boyle’s law, that at constant temperature the volume of a gas diminishes in proportion as the
pressure increases; of Gay-Lussac’s law, that all gases expand equally for equal rise of
temperature, provided pressure is kept constant; the condition being that equal volumes of
gases contain equal numbers of molecules. A striking support is lent to this chain of
reasoning by the facts discovered by Thomas Graham (1805–1869), professor at University
College, London, and subsequently master of the Royal Mint. Graham discovered that the
rate of diffusion of gases into each other is inversely as the square roots of their densities.
For instance, the density of hydrogen being taken as unity, that of oxygen is sixteen times as
great; if a vessel containing hydrogen be made to communicate with one containing oxygen,
the hydrogen will pass into the oxygen and mix with it; and, conversely, the oxygen will
pass into the hydrogen vessel. This is due to the intrinsic motion of the molecule of each gas.
And Graham found, experimentally, that for each volume of oxygen which enters the
hydrogen vessel four volumes of hydrogen will enter the oxygen vessel. Now, 4 = √16; and
as these masses are relatively 1 and 16, and their temperatures are equal, the square of their
velocities are respectively 1 and 16.
The question of the molecular complexity of gases being thus disposed of, it remains to
be considered what are the relative complexity of liquid molecules. The answer is indicated
by a study of the capillary phenomena of liquids, one method of measuring which is the
height of their ascent in narrow or capillary tubes. We shall not enter here into detail as to
the method and arguments necessary; suffice it to say that the Hungarian physicist Eötvös
was the first to indicate the direction of research, and that Ramsay and Shields succeeded in
proving that the complexity of the molecules of most liquids is not greater than that of the
gases which they form on being vaporized; and also that certain liquids, e.g., water, the
alcohols, and other liquids, are more or less “associated,” i.e., their molecules occur in
couplices of two, three, four, or more, and as the temperature is raised the complexity of
molecular structure diminishes.
As regards the molecular complexity of solids, nothing definite is known, and,
moreover, there appears to be no method capable of revealing it.
While the researches of which a short account has now been given have led to
knowledge regarding the nature of molecules, the structure of the molecule has excited

interest since the early years of the century, and its investigation has led to important results.
The fact of the decomposition of acidified water by an electric current, discovered by
Nicholson and Carlisle, and of salts into “bases” and “acids” by Berzelius and Hisinger in
1803, led to the belief that a close connection exists between electric energy, or, as it was
then termed, “electric force,” and the affinity which holds the constituents of chemical
compounds in combination. In 1807 Davy propounded the theory that all compounds consist
of two portions, one electro-positive and the other electro-negative. This idea was the result
of experiments on the behavior of substances, such, for example, as copper and sulphur—if
portions of these elements be insulated and then brought into contact they become
oppositely electrified. The degree of electrification is intensified by rise of temperature until,
when combination ensues, the electrification vanishes. Combination, therefore, according to
Davy, is concurrent with the equalization of potentials. In 1812 Berzelius brought forward
an electro-chemical theory which for the following twenty years was generally accepted. His
primary assumption was that the atoms of elements, or, in certain cases, groups of atoms, are
themselves electrified; that each atom, or group of atoms, possesses two poles, one positive,
the other negative; that the electrification of one of these poles predominates over that of the
other, so that the atom or group is itself, as a whole, electro-positive, or electro-negative;
that combination ensued between such oppositely electrified bodies by the neutralization,
partial or complete, of their electric charges; and, lastly, that the polarity of an element or
group could be determined by noting whether the element or group separated at the positive
or at the negative pole of the galvanic battery, or electrolysis. For Berzelius, oxygen was the
most electro-negative and potassium the most electro-positive of the elements, the bridge
between the “non-metals” and the “metals” being hydrogen, which, with nitrogen, forms a
basic, or electro-positive, group, while with chlorine, etc., it forms electro-negative groups.
The fact that an electric current splits compounds in solution into two portions led Berzelius
to devise his “dualistic” system, which involved the assumption that all compounds consist
of two portions, one electro-positive, the other electro-negative. Thus sulphate of
magnesium and potassium was to be regarded as composed of electro-positive potassium
sulphate in combination with electro-negative magnesium sulphate; the former in its turn
consisted of electro-negative sulphur trioxide (SO3) in combination with electro-positive
oxide of potassium (K2O); while each of these proximate constituents of potassium sulphate
were themselves composed of the electro-negative oxygen in combination with electro-
positive sulphur, or potassium. On contrasting sulphur with potassium, however, the former
was considered more electro-negative than the latter; so that the group SO3 as a whole was
electro-negative, while K2O was electro-positive. The symbols given above, which are still
in universal use, were also devised by Berzelius for the purpose of illustrating and
emphasizing his views. These views, however, met with little acceptance at the time in
England.
Lavoisier’s idea, that oxygen was the necessary constituent of all acids, began about this
time to lose ground. For Davy had proved the elementary nature of chlorine; and
hydrochloric acid, one of the strongest, was thus seen to contain no oxygen, and Davy
expressed the view, founded on his observation, that iodic “acid,” I2O5, was devoid of acid
properties until dissolved in water, and that the essential constituent of all acids was
hydrogen, not oxygen. The bearing of this theory on the dualistic theory is, that while, e.g.,

sulphuric acid was regarded by Berzelius as SO3, containing no hydrogen, and was supposed
to be separated as such at the positive pole of a battery, Davy’s suggestion led to the
opposite conclusion that the formula of sulphuric acid is H2SO4, and that by the current it is
resolved into H2 and SO4. Faraday’s electrolytic law, that when a current is passed through
electrolytes in solution the elements are liberated in quantities proportional to their
equivalents, led to the abandonment of the dualistic theory. For when a current is passed in
succession through acidified water, fused lead chloride, and a solution of potassium
sulphate, the quantities of hydrogen and oxygen from the water, of lead and chlorine from
the lead chloride, and the potassium of the sulphate are in accordance with Faraday’s law.
But in addition to the potassium there is liberated at the same pole an equivalent of
hydrogen. Now, if Berzelius’s theory be true, the products should be SO3 and K2O, but if the
opposite view be correct, then K2 is liberated first and by its subsequent action on water it
yields potash and its equivalent of hydrogen. This was pointed out first by Daniell, professor
at King’s College, London, and it was regarded as a powerful argument against Berzelius’s
system. In 1833, too, Graham investigated the phosphoric acids, and prepared the salts of
three, to which he gave the names, ortho-, pyro-, and meta- phosphoric acids. To understand
the bearing of this on the doctrine of dualism it must be remembered that P2O5, pentoxide of
phosphorus, was at that date named phosphoric acid. When dissolved in water it reacts with
bases, forming salts—the phosphates. But the quantity of water necessary was not then
considered essential; Graham, however, showed that there exist three series of salts—one set
derived from P2O5,3H2O, one from P2O5,2H2O, and a third from P2O5,H2O. His way of
stating the fact was that water could play the part of a base; for example, the ordinary
phosphate of commerce possessed, according to him, the formula P2O5,2Na2O,H2O, two-
thirds of the “water of constitution” being replaced by oxide of sodium. Liebig, then
professor at Giessen (1803–1873), founded on these and on similar observations of his own
the doctrine of poly-basic acids—acids in which one, two, three, or more atoms of hydrogen
were replaceable by metals. Thus, instead of writing, as Graham did, P2O5,2Na2O,H2O, he
wrote, PO4Na2H; and for orthophosphoric acid PO4H3. The group of atoms (PO4), therefore,
existed throughout the whole series of orthophosphates, and could exist in combination with
hydrogen, with hydrogen and metals, or with metals alone. Similarly the group (P2O7) was
characteristic of pyrophosphates and (PO3) of metaphosphates, for P2O5,2H2O=(P2O7)H4;
and P2O5,H2O=2(PO3)H.
The first clear ideas of the structure of the molecule were, however, gained from the
study of the compounds of carbon. It was difficult to apply the dualistic theory to them. For
few of them are electrolytes, and therefore their products of electrolysis, being non-existent,
could not be classified. Nevertheless, Gay-Lussac regarded alcohol, C2H6O, as a compound
of C2H4, ethylene, and H2O, water; and oxalic acid (anhydrous), C2O3, as one of CO2 with
CO. The discovery of “isomeric compounds,” i.e., of compounds which possess the same
ultimate formula and yet differ entirely in their properties, forced upon chemists the
necessity of attending to the structure of the molecule; for only by such a supposition could
the difference between two isomeric bodies be explained. In 1823 Liebig discovered that
silver fulminate and silver cyanate both possessed the empirical formula AgCNO; in 1825

this was followed by the discovery by Faraday that oil gas contains a hydrocarbon identical
in composition with ethylene, C2H4, yet differing from it in properties; and in 1829 Wöhler,
professor in Göttingen (1800–1882), discovered that urea, a constituent of urine, could be
produced by heating ammonium cyanate, NH4CNO, a substance of the same formula. It
therefore became clear that the identity of a compound must depend on some other cause
than its ultimate composition.
In 1833 Liebig and Wöhler took an important step in elucidating this question by their
investigations on benzoic acid and acid obtainable by distilling a resin named gum benzoin.
They showed that this acid, C7H6O2, could be conceived as consisting of the group C7H5O,
to which they gave the name “benzoyl,” in combination with OH; that benzoic aldehyde,
C7H6O, might be regarded as its compound with hydrogen; that it also formed compounds
with chlorine, and bromine, and sulphur, and replaced hydrogen in ammonia (C7H6O,NH2).
They termed this group, benzoyl, a “compound element” or a “radical.” This research was
followed by one by Robert Bunsen, professor at Heidelberg, born in 1811, and recently
(1899) dead, which bore reference to cacodyl, a compound of arsenic, carbon and hydrogen,
in which the idea of a radical was confirmed and amplified.
The idea of a radical having thus become established, Jean Baptiste Andrée Dumas,
professor in Paris (1800–1884), propounded the theory of “substitution,” i.e., that an
element such as chlorine or oxygen (which, be it noticed, is electro-negative on Berzelius’s
scale) could replace hydrogen in carbon compounds, atom for atom, the resulting compound
belonging to the same “type” as the one from which it was derived. And Laurent, warden of
the mint at Paris (1807–1853), and Gerhardt, professor at Montpelier and at Strasburg
(1816–1856), emphasized the fact that one element, be it what it may, can replace another
without fundamentally altering its chemical character, and also that an atom of hydrogen can
be replaced by a group of atoms or radical, behaving for the occasion like the atom of an
element. It is to Laurent and Gerhardt that we owe the definition of an atom—the smallest
quantity of an element which can be present in a compound; an equivalent—that weight of
an element which combines with or replaces one part by weight of hydrogen; and a molecule
—the smallest quantity which can exist in a free state, whether of an element or a
compound. They recognized, too, that a molecule of hydrogen, chlorine, etc., consists of two
atoms.
In 1849 Wurtz, professor in Paris (1817–1884), and Hofmann, then professor in the
College of Chemistry in London, afterwards at Berlin (1818–1892), discovered a series of
compounds allied to ammonia, NH3, in which one or more atoms of hydrogen were replaced
by a group or radical, such as methyl (CH3), ethyl (C2H5), or phenyl (C6H5). Wurtz referred
such compounds to the ammonia “type.” They all resemble ammonia in their physical
properties—smell, taste, etc.—as well as in their power of uniting with acids to form salts
resembling ammonium chloride (NH4Cl), and other ammonium compounds. Shortly
afterwards Williamson, professor at University College, London, added the “water type,” in
consequence of his researches on “mixed ethers”—bodies in which the hydrogen of water
might be regarded as replaced by organic radicals. Thus we have the series:

H. O. H.; CH3. O. H.; CH3. O. CH3; and NH3; NH2; H3; NH(CH3)2; and N(CH3)3; the
first representing compounds following the water type, the latter the ammonia type. This
suggestion had been previously made by Laurent, in 1846. But Williamson extended his
views to inorganic compounds; thus, sulphuric acid was represented as constructed on the
double water type—HO. SO2. OH, being derived from H. O. (H. H) O. H, the two hydrogen
atoms enclosed in brackets being replaced by the radical SO2. To these types Gerhardt added
the hydrogen and hydrogen chloride types, H.H. and H.Cl; and, later, Kekulé, professor in
Bonn (1829), added the marsh gas type C(H)4. The next important step was taken by
Frankland, professor in the Royal School of Mines, London; his work, however, had been
anticipated by Cunn Brown, professor at Edinburgh University, in a pamphlet even yet little
known. It was to attribute to elements one or more powers of combination. To these he gave
the name “valency,” and the capacity of possessing valency was called “quantivalence.”
Thus hydrogen was taken as a “monad,” or monovalent. Chlorine, because it unites with
hydrogen atom to atom, is also a monad. Oxygen, having the power to combine with two
atoms of hydrogen, was termed a dyad, or divalent; nitrogen a triad, or trivalent; carbon a
tetrad, or tetravalent, and so on. This is evident from inspection of the formulas of their
compounds with hydrogen, thus:

H H H
/ \ /
H——Cl; H——O——H; H——N ; C
\ / \
H H H

Instances of penta, hexa, and even hepta-valency are not wanting.
This was the key to unlock the structure of chemical compounds; and Frankland’s
views, just stated, are still held by chemists. The determination of the constitution of
compounds, chiefly those of carbon, occupied the attention of chemists, almost exclusively,
until 1880. The plan of action is much the same as that of a mechanician who wishes to
imitate a complicated mechanism. He must first dissect it into groups of mechanical
contrivances; these are next constructed; and they are finally built together into the complete
machine. In certain cases the atoms of carbon are arranged in “chains,” as, for example, in
pentyl alcohol:

H3 C——C——C——C——C——O——H
H2 H2 H2 H2

each atom being tetrad, and its “affinities,” or powers of combination, saturated either with
hydrogen or with those of neighboring atoms of carbon; in others they are in the form of a
“ring,” as in benzene, the formula of which was first suggested by Kekulé, viz.:

H H
C——C
/ \
HC CH;
\ /
C==C
H H

or in both, as in ethyl benzene,

H H
C——C
/ \ H H
HC C——C——CH.
\ / H H
C==C
H H

One or more atoms of nitrogen, or of oxygen, may form part of the circle, as in pyridine:

H H H H
C——C C C
/ \ /
N CH and furfurane, O == ,
\ / \
C==C C C
H H H H

and so on. By means of conceptions such as these many interesting compounds have been
built up out of the elements which they contain; e.g., urea and uric acid, constituents of
urine; theobromine and caffeine, the essential principles of cocoa and tea; alizarine and
indigo, valuable dyestuffs; and several of the alkaloids, bitter principles contained in plants,
of great medicinal value.
They have led, too, to the discovery of many brilliant colors, now almost universally
employed, to the exclusion of those less brilliant, because less pure, derived from plants, and
in one or two cases from animals; the manufacture of gun-cotton, dynamite, and similar high
explosives; and to the development of the candle industry; the sugar manufacture; to
improvement in tanning, in brewing, and in the preparation of gas and oils for illuminating

purposes. In short, it may be said that the industrial progress of the latter half of the century
has been due to the theoretical views of which a short sketch has just been given.
Such formulas, however, can evidently not represent the true constitution of matter,
inasmuch as the atoms are imagined to lie on a plane, whereas it is evident that they must
occupy space of three dimensions and possess the attributes of solidity. The conception
which led to the formulation of such views was due first to Pasteur, in his later years director
of the institute known by his name at Paris, and more directly to LeBel and Van’t Hoff, now
professor at Berlin, independently of each other. In 1848 Pasteur discovered that it was
possible to separate the two varieties of tartaric acid from each other; and that that one
which rotated the plane of polarized light to the right gave crystals with an extra face,
unsymmetrically disposed with regard to the other faces of the crystal. The variety, the
solution of which in water was capable of producing left-handed rotation, also possessed a
similar face, but so placed that its reflection in a mirror reproduced the right-handed variety.
Pasteur also showed that a mixture of these acids gave crystals not characterized by an
unsymmetrically placed face; and also that the solution was without action on polarized
light. These observations remained unexplained, until LeBel and Van’t Hoff, in 1874,
simultaneously and independently devised a theory which has, up till now, stood the test of
research. It is briefly this: Imagine two regular tetrahedra, or three-sided pyramids, standing
each on its triangular base. An idea can best be got by a model, easily made by laying on a
table three lucifer matches so as to form an equilateral triangle, and erecting a tripod with
three other matches, so that each leg of the tripod stands on one corner of the triangle. At the
centre of such a tetrahedron, an atom of carbon is supposed to be placed. Marsh gas, CH4, is
supposed to have such a structure, each corner, or solid angle of the structure (of which there
are four), being occupied by an atom of hydrogen. This represents the solid or
stereochemical formula of methane or marsh gas. Now, suppose one of the atoms of
hydrogen in each of these structures to be replaced by chlorine, the group (OH), or any other
monovalent element or group. It is evident that if not exactly similar (owing to the
replacement not having been made at similar corners in each), the two structures can be
made similar by turning one of them round, until the position of the substituting atom or
group (which we will term X) coincides in position with X in the stationary one. If two such
replacements be made, say, with X and Y in each, coincidence can again be made to take
place; but the same is not the case if X, Y, and Z replace three atoms of hydrogen in the
structure; for there is one way of replacement which is the optical image of the other, and
represents the other’s reflection in a mirror.

(Tetrahedron XYZ) and (Tetrahedron XZY)

Now, it is found that when the four corners of such a structure are occupied by four
separate atoms or groups, or when (as the expression goes) the body contains an
“asymmetrical carbon atom,” if the substance or one of its derivations can be obtained in a

crystalline form, the crystals are also asymmetric, i.e., arc develops a face which is the
mirror-reflection of a similar face developed on the other variety; and if a beam of polarized
light be passed through the solution of the substance, its plane is rotated to the left if one
variety be used, and, if the other, to the right. This hypothesis of LeBel’s and Van’t Hoff’s
has had an enormous influence on the progress of organic chemistry. By its means Fischer,
now professor at Berlin, has explained the reason of the existence of the enormous number
of bodies analogous to grape and cane sugar, and has prepared many new varieties; and it
appears likely that the terpenes, a class of bodies allied to turpentine, and comprising most
of the substances to which the odor of flowers is due, may thereby find their explanation. It
may be mentioned in passing that Pasteur, having found that ordinary mould destroyed one
variety of tartaric acid rather than the other in a mixture of the two, and made use of this
observation in order to prepare the unattached variety in a state of purity, was led to study
the action of organisms more or less resembling mould; and that this has led to the
development of the science of bacteriology, which has had an enormous influence on our
views regarding fermentation in general, and guides the work of our physicians, our
surgeons (witness Lister’s antiseptic treatment), our sanitary engineers in their estimate of
the purity of drinking-water and of the disposal of sewage, of our manufacturers of beer and
spirits, of wine-growers, and more recently of farmers. All these processes depend upon the
action of organisms in producing chemical changes, whether in the tissues of the body,
causing or curing disease, or in the production of flavored alcohol from sugar, or in the
manufacture of butter and cheese, or in preparing the land for the reception of crops. We also
owe to the genius of Van’t Hoff the most important advance of recent times in the region of
physical chemistry. It has been observed by Raoult, professor at Grenoble, that the freezing-
point of a solvent as a general rule is lowered to the same extent if there be dissolved in it
quantities of substances proportional to their molecular weights. Thus, supposing 1.80 grams
of grape-sugar be dissolved in 100 grams of water and the solution cooled below 0° with
constant stirring, ice separates suddenly in thin spicules, and the temperature rises to
−0.185°. If 3.42 grams of cane-sugar be similarly dissolved in 100 grams of water, the
freezing-point of the solution is again −0.185°. Now, 1.80 and 3.42 are respectively the
hundredth part of the molecular weights of grape-sugar (C6H12O6) and cane-sugar
(C12H22O11). Similarly, Raoult found that quantities proportional to molecular weights
dissolved in a solvent depress the vapor pressure of that solvent equally, or, what comes to
the same thing, raise its boiling-point by an equal number of degrees. But ordinary salts,
such as sodium chloride, potassium nitrate, etc., dissolved in water, give too great a
depression of the freezing-point and too high a boiling-point. Next, it has been observed by
botanists, Devries, Pfeffer, and others, who had examined the ascent of sap in plants, that if a
vessel of unglazed porcelain, so treated as to cause a film of cupric ferrocyanide (a slimy red
compound) to deposit in the pores of its walls, be filled with a weak (about 1 per cent.)
solution of sugar or similar substance, and plunged in a vessel of pure water, water entered
through the pores. By attaching a monometer to the porous vessel the pressure exerted by
the entering water could be measured. Such pressure was termed “osmotic pressure,”
referring to the “osmosis” or passage through the walls of the vessel. Such prepared walls
are permeable freely to water, but not to sugar or similar bodies. Van’t Hoff pointed out that
the total pressure registered is proportional to the amount of substance in solution, and that it
is proportional to the absolute temperature, and he showed, besides, that the pressure exerted

by the sugar molecules is the same as that which would be exerted at the same temperature
were an equal number of molecules of hydrogen to occupy the same volume as the sugar
solution. This may be expressed by stating that when in dilute solution sugar molecules
behave as if they were present in the gaseous state. Here again, however, it was noticed that
salts tended to give a higher pressure; it was difficult to construct a semi-permeable
diaphragm, however, which would resist the passage of salt molecules, while allowing those
of water to pass freely. Lastly, Arrhenius, of Stockholm, had shown that the conductivity of
salt solutions for electricity may be explained on the assumption that when a salt, such as
KNO3 is dissolved in water, it dissociates into portions similar in number and kind to those
it would yield if electrolyzed (and if no secondary reactions were to take place). Such
portions (K and NO3, for example) had been named ions by Faraday. The conductivity of
such solutions becomes greater, per unit of dissolved salt, the weaker the solution, until
finally a limit is reached, after which further dilution no longer increases conductivity. Now
Van’t Hoff united all these isolated observations and showed their bearing on each other.
Stated shortly, the hypothesis is as follows: When a substance is dissolved in a large quantity
of a solvent, its molecules are separated from each other to a distance comparable with that
which obtains in gases. They are, therefore, capable of independent action; and when placed
in a vessel the walls of which are permeable to the solvent, but not to the dissolved
substance (“semi-permeable membrane”), the imprisoned molecules of the latter exert
pressure on the interior surface of these walls as if they were gaseous. Van’t Hoff showed the
intimate connection between this phenomenon and the depression of freezing-point and the
use of vapor pressure already alluded to. He pointed out further that the exceptions to this
behavior, noticed in the case of dissolved salts, are due to their “electric dissociation,” or
“ionization,” as it is now termed; and that in a sufficiently dilute solution of potassium
nitrate, for example, the osmotic pressure, and the correlated depression of freezing-point
and rise of boiling-point, are practically equal to what would be produced were the salt to be
split into its ions, K and NO3. These views were vigorously advocated by Ostwald, professor
at Leipzig, in his Zeitschrift für physikalische Chemie, and he and his pupils have done
much to gather together facts in confirmation of this theory, and in extending its scope.
It must be understood that the ions K and NO3 are not, strictly speaking, atoms; they are
charged atoms; the K retains a +, and the NO3 a − charge. On immersing into the solution
the poles of a battery, one charged + and the other −, the + K atoms are attracted to the −
pole, and are there discharged; as soon as they lose their charge they are free to act on the
water, when they liberate their equivalent of hydrogen. Similarly, the − NO3 groups are
discharged at the + pole, and abstract hydrogen from the water, liberating an equivalent
quantity of oxygen. Thus the phenomenon of electrolysis, so long a mysterious process,
finds a simple explanation. The course of ordinary chemical reactions is also readily realized
when viewed in the light of this theory. Take, for example, the ordinary equation:
AgNO3.Aq + NaCl.Ag = AgCl + NaNO3.Aq;

i.e., solutions of silver nitrate and sodium chloride give a precipitate of silver chloride,
leaving sodium nitrate in solution. By the new views, such an equation must be written:

+ − + − + −
Ag.Aq + NO3 .Aq + Na.Aq + Cl.Aq = AgCl + Na.Aq + NO3 .Aq.

The compound, silver chloride, being insoluble in water, is formed by the union of the
ions Ag and Cl, and their consequent discharge, forming an electrically neutral compound;
while the sodium ions, charged positively together with the NO3 ions, negatively charged,
remain in solution.
One more application of the principle may be given. Many observers—Andrews, Favre,
and Silbermann, but especially Julius Thomsen, of Copenhagen, and M. Berthelot, of Paris
—have devoted much labor and time to the measurement of the heat evolved during
chemical reactions. Now, while very different amounts of heat are evolved when chlorine,
bromine, or iodine combine respectively with sodium or potassium, the number of heat units
evolved on neutralizing sodium or potassium hydroxide with hydrochloric, hydrobromic,
hydriodic, or nitric acids is always about 13,500. How can this fact be explained? It finds its
explanation as follows: These acids and bases are ionized in solution as shown in the
equation:

+ − + − + −
H.Aq + Cl.Aq. + Na.Aq + OH.Aq = H.OH + Na.Aq + Cl.Aq.

Water is the only compound formed; and it is produced by the union of the hydrogen-ion
originally belonging to the acid, and the OH or hydroxyl-ion originally belonging to the
base. No further change has occurred; hence the uniform evolution of heat by the interaction
of equivalent quantities of these acids and bases.
It now remains to give a short account of the greatest generalization which has as yet
been made in chemistry. It has been termed the “Periodic Arrangement of the Elements.”
In 1864 Newlands, of London, and Lothar Meyer, late of Tübingen, found that by
arranging the elements in the order of their atomic weights certain regularities were to be
observed between each element, and in general the eighth in succession from it, in the order
of their numerical value. Such similar elements formed groups or quantities; while the
elements separating them belong to a period, hence the name “periodic arrangement.”
Commencing with lithium, a light, lustrous metal found in silicate in certain minerals, we
have the following series:
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
7 9.2 11 12 14 16 19 20
Sodium Magnesium Aluminum Silicon Phosphorus Sulphur Chlorine Argon
23 24.3 27 28 31 34 35.5 40

and so on. It is unnecessary to point out in detail the resemblances between the elements
which stand in the vertical columns; but it may be stated that the resemblance extends also
to the formulas and properties of their compounds. Thus the chlorides of lithium and sodium

are each white soluble salts, of the formulas LiCl and NaCl; oxides of magnesium and of
beryllium are both insoluble white earthy powders, MgO and BeO (GeO), and so on.
Newlands, in his preliminary sketch, termed this order the “Law of Octaves,” and predicted
the existence of certain undiscovered elements which should occupy unfilled positions in the
table. Mendeléef, professor at St. Petersburg, in 1869 amplified and extended these
relations; and he and Meyer pointed out that the volume occupied by equal numbers of
atoms of such elements underwent a periodic variation when the elements are classified as
above. The prediction of undiscovered elements was made by Mendeléef in a more assured
manner; and in several cases they have been realized. Thus what Mendeléef called
“ekaboron” has since been discovered by Lecoq de Boisbandron and named, patriotically,
“gallium”; Mendeléef’s “eka-silicon” is now known as “germanium,” discovered by
Winkler; and “eka-aluminum” is now Cléve’s “scandium.” Moreover, the atomic weights of
cæsium, beryllium, molybdenium, and mercury have been altered so that they fit the
periodic table; and further research has justified the alteration.
The valency of these elements increases from right to left, as will be seen by inspection
of the following series:
LiCl BeCl3 BCl3 CCl4 NH4Cl
Na2O MgO B2O3 SiO2 PCl3
Monad. Dyad. Triad. Tetrad. Triad and Pentad.
OH2 FH Ne——
SO3 Cl(OH)O3 A——
Dyad and Hexad. Monad and Heptad. No valency.

The elements of no valency are of recent discovery. In 1894 Lord Rayleigh had
determined the density of the nitrogen of the atmosphere, having separated from it the
oxygen and carbon dioxide which is mixed with nitrogen in air. He found it to be of
somewhat higher density than that obtainable from ammonia and other compounds of
nitrogen. In conjunction with Ramsay he investigated atmospheric nitrogen; it was absorbed
either by a method devised by Cavendish, or by making it combine with magnesium at a red
heat. They found that the unabsorbable residue possessed an unknown spectrum, and that its
density was nearly 20. To this new gas they gave the name “argon,” or inactive, seeing that
all attempts to cause it to enter into combination had failed. In 1895 Ramsay, searching for
possible combinations of argon in minerals, experimented with one which had been
previously examined by Hillebrand, of Baltimore, and obtained from it helium, a gas of
density 2, possessing a spectrum which had been previously discovered in 1868 in the
chromosphere of the sun, by Jannsen, of Paris, and named helium by Frankland and
Lockyer. Subsequent liquefaction of crude argon by means of liquid air, prepared by a
process invented simultaneously by Linde and Hampson, gave a residue which was named
by its discoverers, Ramsay and Travers, “neon.” Liquid argon has yielded two other gases
also, “krypon” and “xenon.” These elements form a separate group in the Periodic Table,
commencing with helium, with atomic weight, 4; neon, 20; argon, 40; krypon, 82; and
xenon, 128. They all agree in being mono-atomic, i.e., their molecules consist of single
atoms; and they have no tendency to form compounds, i.e., they possess no valency.

In this sketch of the progress of chemistry during the century which has just passed,
attention has been paid chiefly to the progress of thought. Allusions must, however, be made
to the applications of chemistry to industrial purposes. The development of the soda
industry, the preparation of carbonate of soda and caustic from common salt—initiated in
France by LeBlanc (1742–1806)—has been developed by Tennant, in Scotland, and
Muspeath and Gossage, and by Hargreaves, Weldon, and Maetea, in England; this process
has at present a serious rival in the ammonia-soda process, developed by Solway, in
Belgium, and by Brunner and Mond, in England. The main action of sulphuric acid, so long
associated with the alkali process, has made enormous strides during the present century, but
is still, in the main, the original process of causing sulphur dioxide in presence of water to
absorb the oxygen of the air through nitric oxide. But the saving of the oxides of nitrogen
through the invention of a sulphuric acid power by Gay-Lussac, known by his name, and the
re-utilization of these oxides in the “Glover” power, invented by John Glover, of Newcastle,
have greatly lessened the cost of the acid. Concentration of the acid in iron vessels is now
common, the cost of platinum or of fragile glass vessels being thereby saved. The
desulphurization of iron and the removal of silicon, carbon, and phosphorus by Bessemer’s
process, modified by Thomas and Gilchrist through the introduction of a “basic magnesia
lining” for the convertors, has made it possible to obtain pure iron and steel from ores
previously regarded as of little value.
The use of artificial manures, prepared by mixing refuse animal matters with tetra-
hydrogen, calcium phosphate, and nitrate of soda, or sulphate of ammonia, first introduced
by Liebig, has created a revolution in agricultural methods and in the weight of crops
obtainable from a given area of soil. The influence of manures on crops has been fully
studied by Lawes and Gilbert for more than fifty years in their experimental farm at
Rothampstead. The most remarkable advances which have been made, however, are due to
cheap electric current. The electrolysis of alumina, dissolved in fused cryolite to obtain
aluminum, an operation carried out at Schaffhausen-on-the-Rhine, and at the Falls of Foyers,
in Scotland; the electro-deposition of pure copper for electric wires and cables, electro-
silvering, gilding, and nickelling, all these are instances where decomposition of a
compound by the electric current has led to important industrial results. At present soda and
chlorine are being manufactured by the electrolysis of salt solution contained in rocking
trays, one of the electrodes being mercury, by the Castner-Kellner process. This manufacture
is being carried on at Niagara, as well as in England. But electricity as a heating agent finds
ever-extending application. Louis Moisson, professor at Paris, led the way by utilizing the
enormous heat of the ore in his electric furnace, thereby, among other interesting reactions,
manufacturing diamonds, small, it is true, though none the less real. The use of electricity as
a heating agent has received new applications. Phosphorus is now made by distilling a
mixture of phosphates of lime and alumina with coke; a new polishing agent has been found
in “carborundum,” a compound of carbon and silicon, produced by heating in an electric
furnace a mixture of sand and coke; and cyanide of potassium, almost indispensable for the
extraction of gold from ores poor in gold, is now manufactured by heating a mixture of
carbon and carbonate of barium in an electric furnace in a current of carbon monoxide.
These are but some of the instances in which electricity has been adopted as an agent in
effecting chemical changes; and it may be confidently predicted that the earlier years of the
twentieth century will witness a great development in this direction. It may be pointed out

that the later developments of industrial chemistry owe their success entirely to the growth
of chemical theory; and it is obvious that that nation which possesses the most competent
chemists, theoretical and practical, is destined to succeed in the competition with other
nations for commercial supremacy and all its concomitant advantages.

William Ramsay.

ARCHÆOLOGY

T o possible,
write of the progress of archæology in this century is scarcely
as the idea of the subject was unknown a hundred years ago;
it is, therefore, the whole history of its opening and development that we
have to deal with. The conception of the history of man being preserved to
us in material facts, and not only in written words, was quite disregarded
until the growth of geology had taught men to read nature for themselves,
instead of trusting to the interpretations formed by their ancestors. Even
down to the present the academic view is that classical archæology is more
important than other branches, because it serves to illustrate classical
literature. Looked at as archæology, it is, on the contrary, the least important
branch, because we already know so much more of the classical ages than
we do of others.

It is only within the present generation that it has been realized that
wherever man has lived he has left the traces of his action, and that a
systematic and observant study of those remains will interpret to us what
his life was, what his abilities and tastes were, and the extent and nature of
his mind. Literature is but one branch of the archæology of the higher races;
another—equally important for the understanding of man—is art; these two
give the highest and most complex and characteristic view of the nature of a
race. At the opposite end of the scale are the rudest stone weapons which
remain as the sole traces of the savages who used them. These highest and
lowest evidences of mind, and all that lies between them, are the domain of
archæology.
We now purpose to review the growth of archæology in contact with
geology, where it concerns man as the last of the links of life on the globe;

and then to notice the archæology of each country in turn, as it leads on to
the times of historical record, and so passes down to modern times.
A century ago the world of thought was divided between the old and
new ideas very differently from what is now the case. Then there stood on
one side the idea of a special creation of an individual man, at 4000 B. C.;
the compression of all human history into a prehistoric age of about three
thousand years, and a fairly logical solution of most of the difficulties of
understanding in a comfortable teleology. On the other hand stood many
who felt the inherent improbability of such solutions of the problem of life,
and who were feeling their way to some more workable theory on the basis
of Laplace, Lamarck, Erasmus Darwin, and others; vaguely mingling
together questions of physics, geology, archæology, anthropology, and
theology, each of which we now see must be treated on its own basis, and
be decided on internal evidence, before we can venture to let it affect our
judgment on other points.
The great new force which thrust itself in to divide and decide on these
questions is the scientific study of man and his works. Strangely shaped
flints had been noticed, but no one had any knowledge of their age. One
such, when found with the bones of a mammoth, was attributed to the
Roman age, because no person could have brought elephants into Britain
except some Roman general. The argument was excellent and irrefutable
until geology found plenty more remains of the mammoth and showed that
it was here long before the Romans. It was less than half a century ago that
our eyes began to open to the abundant remains of flint-using man. Then a
single rude stone weapon was an unexplained curiosity; now an active
collector will put together his tens of thousands of specimens, will know
exactly where they were found, their relation of age and of purpose, and
their bearing on the history of man.
Not only have worked flint implements been found in the river gravels
of France and England, where they were first noticed in the middle of this
century, but also in most parts of Europe, in Egypt on the high desert, in
Somaliland, at the Cape of Good Hope, in India, America, and other
countries; and the most striking feature is the exact similarity in form
wherever they have been found. So precisely do the same types recur, so
impossible would it be to say from its form whether a flint had been found
in Europe, Asia, or Africa, that it appears as if the art of working had spread

from some single centre over the rest of the world. This is especially the
case with the river-gravel flints—the earlier class—usually called
Paleolithic. Soon after the general division had been made between polished
stone-work of the later or Neolithic times, found on the surface, and the
rough chipped work of the earlier or Paleolithic times, found in geological
deposits, a further sub-division was made by separating the Paleolithic age
into that of the river gravels and that of the cave-dwellers. The latter has
again been divided into three classes by French writers, named, from their
localities, Mousterien, Solutrien, Magdalenien; and, though these classes
may be much influenced by locality, they probably have some difference of
age between them.
And now within the last few years a still earlier kind of workmanship
has been recognized in flints found in England on the high hills in Kent.
Though at first much disputed, the human origin of the forms is now
generally acknowledged, and they show a far ruder ability than even the
most massive of the Paleolithic forms. The position also of these flints, in
river deposits lying on the highest hills some six hundred feet above the
present rivers, shows that the whole of the valleys has been excavated since
they were deposited, and implies a far greater age than any of the gravel
beds of the Paleolithic ages.
We, therefore, have passed now at the beginning of this century to a far
wider view of man’s history, and classify his earlier ages in Europe thus:

First—Eolithic: Rudest massive flints from deposits 600 feet
up.
Second—Paleolithic: Massive flints from gravels 200 feet up
and less (Achuleen).
Third—Paleolithic—Cave-dwellers: Flints like the preceding
and flakes (Mousterien).
Fourth—Paleolithic—Cave-dwellers: Flints well worked and
finely shaped (Solutrien).
Fifth—Paleolithic—Cave-dwellers: Abundant bone working
and drawing (Magdalenien).

Sixth—Neolithic: Polished flint working, pastoral and
agricultural man.

What time these periods cover nothing yet proves. The date of 4000
B. C. for man’s appearance, with which belief the nineteenth century started,
has been pushed back by one discovery after another. Estimates of from
10,000 to 200,000 years have been given from various possible clews. In
Egypt an exposure of 7000 years or more only gives a faint brown tint to
flints lying side by side with Paleolithic flints that are black with age. I
incline to think that 100,000 years B. C. for the rise of the second class, and
10,000 B. C. for the rise of the sixth class will be a moderate estimate.
Passing now from Paleolithic man of the latest geological times whose
works lie under the deposit of ages, to Neolithic man of surface history
whose polished stone tools lie on the ground, we find also how greatly
views have changed. For ages past metal-using man has looked on the
beautifully polished or chipped weapons of his forefathers as
“thunderbolts,” possessing magic powers, and he often mounted the smaller
ones to wear as charms. At the beginning of this century well-finished stone
weapons were only preserved as curiosities which might belong to some
remote age, but without any definite ideas about them. The recognition of
long ages of earlier unpolished stone work has now put these more
elaborate specimens to a comparatively late period, and yet they are
probably older than the date to which our forefathers placed the creation of
man.
The beginning of a more intelligent knowledge of such things was laid
by the systematic excavations of the burial mounds scattered over the south
of England, which was done in the early part of this century by Sir Richard
Colt Hoare. A solid basis of facts was laid, which began to supersede the
romances woven by Stukeley and others in the last century. Gradually more
exact methods of search were introduced, and in the last thirty years Canon
Greenwell has done much, and General Pitt Rivers has established a
standard of accurate and complete work with perfect recording, which is the
highest development of archæological study. These and other researches
have opened up the life of Neolithic man to us, and we see that he was
much as modern man, if compared with the earlier stage of man as a hunter.
The Neolithic man made pottery, spun and wove linen, constructed

enormous earthworks both for defence and for burial, and systematically
made his tools of the best material he could obtain by combined labor in
mining. The extensive flint-mines in chalk districts of England show long-
continued labor; and the perfect form and splendid finish of many of the
stone weapons show that skilled leisure could be devoted to them, and that
æsthetic taste had been developed. The large camps prove that a thorough
tribal organization prevailed, though probably confined to small clans.
About the middle of the century a new type of dwelling began to be
explored—the lake dwelling; this system of building towns upon piles in
lakes had the great advantage of protection from enemies and wild beasts,
and a constant supply of food in the fish that could be hooked from the
water below. Though such settlements were first found in the Swiss lakes,
and explored there by Keller, they have since been found in France,
Hungary, Italy, Holland, and the British Isles. The earlier settlements of this
form belong to the Neolithic age, but only in central Europe. In these
earliest lake dwellings weaving was known, and the cultivation of flax,
grapes, and other fruit and corn; while the usual domestic animals were kept
and cattle were yoked to the plough; pottery was abundant, and was often
ornamented with geometric patterns. The type of man was round-headed.
Following the Neolithic lake dwellings came those of the Bronze age, and
as the bronze objects are similar to those found in other kinds of dwellings
we shall notice them in the Bronze age in general. The type of man was
longer-headed than in the earlier lake settlement. The domestication of
animals shows an advance; the horse was common, and the dog, ox, pig,
and sheep were greatly improved. Pottery was better made and elaborately
decorated, often with strips of tin-foil.
The Bronze age marks a great step in man’s history. In many countries
the use of copper, hardened by arsenic or oxide, was common for long
before the alloy of copper and tin was used. In other countries, where the
use of metals was imported, copper only appears as a native imitation of the
imported bronze. Hence there is a true age of copper in lands where the use
of metals has grown. It must by no means be supposed that copper excluded
the use of flint; it was not until bronze became common that flint was
disused. The existence of a Bronze age was first formulated, as distinct
from a Stone age, about seventy years ago; and the existence of a Copper

age has been much disputed in the last thirty years, but has only been
proved clearly ten years ago, in Egypt.
In the eighteenth century the bronze weapons found in England were
attributed to the Romans by some writers, though others, with more reason,
argued that they were British. In the first year of the century began the
comparative study of such weapons with reference to modern savage
products. The development of the metal forms from stone prototypes was
pointed out in 1816; the tracing out of the succession of the forms and the
modes of use appeared in 1847. Further study cleared up the details, and
within the last twenty years the full knowledge of the Bronze age in other
countries has left no question as to the general facts of the sequence of its
history. In each type of tool and weapon there appears first a very simple
form imitated from the stone implements which were earlier used.
Gradually the facilities given by the casting and toughness of the metal
were used, and the forms were modified; ornamentation was added, and
thin work in embossed patterns gave the stiffness and strength which had
been attained before by massive forms. The general types are the axe—first
a plain slip of metal, later developed with a socket; then the chisel, gouge,
sickle, knife, dagger, sword, spear, and shield; personal objects, as pins,
necklets, bracelets, ear-rings, buttons, buckles, and domestic caldrons and
cups. Most of these forms were found together, all worn out and broken, in
the great bronze-founder’s hoard at Bologna.
Lastly in the prehistory of Europe comes the Iron age, which so much
belongs to the historical period that we can best consider it in noticing
separate countries.
From the recent discoveries in Egypt we can gain some idea of the date
of these periods. We ventured to assign about 10,000 B. C. for the rise of the
Neolithic or polished-stone period (it may very possibly be earlier); the
beginning of the use of copper may be placed about 5000 B. C.; the
beginning of bronze was perhaps 3000 or 2000 B. C., as its free use in Egypt
is not till 1600 B. C.; and the use of iron beginning about 1000 B. C., probably
in Armenia, spreading thence through Europe until it reached Italy, perhaps
700 years B. C., and Britain about 400 B. C. Such is the briefest outline of the
greater part of the history of man, massed together in one general term of
“prehistoric,” before we reach the little fringe of history nearest to our own
age. The whole of this knowledge results from the work of the century.

We now turn to the historical ages of each of the principal countries, to
review what advance has been made even where a basis of written record
has come down to us, equally accessible in all recent times.

EGYPT

At the beginning of the century Egypt was a land of untouched and
inexplicable mystery; the hieroglyphics were wondered at, and puzzled
over, without any idea of how they were to be read, whether as symbols or
as letters. The history was entirely derived from the confused accounts of
Greek authors, the lists remaining of Manetho’s history, written about 260
B. C., and the allusions in the Bible. The attempt to make everything fit to
the ideas of the Greeks, and to make everything refer to the Biblical history,
greatly retarded the understanding of the monuments, and is scarcely
overcome yet. The first great step forward was when an inscription was
found at Rosetta, in 1799, written in two methods, the monumental
hieroglyphic and the popular demotic, along with a Greek version. By 1802
some groups of each writing had been translated. Young identified more
signs, and Gell, by 1822, could successfully apportion three-quarters of the
signs to the Greek words. The next step was to apply the modern Coptic
language, descended from the ancient Egyptian, to the reading of the words.
Gell had been doing so, but it needed a student of Coptic—Champollion—
to carry this out thoroughly, as he did in 1821–32. Since then advance in
reading has been only a matter of detail, not requiring any new principles.
The knowledge of the art began with the admiration for the debased
work of Roman times, the principal interest at the beginning of the century.
Then the excavations among the Rameside monuments at Thebes, about
1820–30, took attention back to the age of 1500–1000 B. C. The work of
Lepsius, and later of Mariette, from 1840–80, opened men’s eyes to the
splendid work of the early dynasties, about 4000–3000 B. C. And lastly the
excavations of 1893–99 have fascinated scholars by a view of the rise of the
civilization and the prehistoric period before 5000 B. C.
Throughout the greater part of the century the archæology of Egypt lay
untouched; all attention was given to the language; and even Gardner
Wilkinson’s fine view of the civilization (1837) depended largely on Greek

authors, and had no perspective of history in tracing changes and
development. It is only in the last ten or fifteen years that any exact
knowledge has been acquired about the rise and progress of the various arts
of life; this study now enables us to date the sculpture, metal work, pottery,
and other art products as exactly as we can those of the Middle Ages.
The view that we now have of the rise and decay of this great
civilization and its connection with other lands is more complete and far-
reaching than that of any other country. In the early undated age, before the
monarchy which began about 4800 B. C., a flourishing civilization was
spread over upper Egypt. Towns were built of brick, as in later times;
clothing was made of woven linen and of leather; pottery was most skilfully
formed, without the potter’s wheel, hand-made, yet of exquisite regularity
and beauty of outline, while the variety of form is perhaps greater than in
any other land; stone vases were made entirely by hand, without a lathe, as
perfect in form as the pottery, and of the hardest rocks, as diorite and
granite; wood was carved for furniture; the art of colored glazing was
common, and was even applied to glazing over large carvings in rock
crystal; ornaments and beads were wrought of various stones and precious
metals; ivory combs with carved figures adorned the hair; ivory spoons
were used at the table; finely formed weapons and tools of copper served
where strength was needful, while more useful were flint knives and lances
which were wrought with a miraculous finish that has never been reached
by any other people; and games were played with dainty pieces made of
hard stone and of ivory. But all this tasteful skill of 6000–5000 B. C. had its
negative side; in the artistic copying of nature the mechanical skill of these
people carried them a very little way; their figures and heads of men and
animals are strangely crude. And they had no system of writing, although
marks were commonly used. They always buried the body doubled up, and
often preserved the head and hands separately. Commerce was already
active, and large rowing-galleys carried the wares of different countries
around the Mediterranean. These people were the same as the modern
Kabyle, of Algeria, and akin to the South European races, but with some
negro admixture. Our whole knowledge of this age has only been gained
within the last five years.
At about 5000 B. C. there poured into Egypt a very different people,
probably from the Red Sea. Having far more artistic taste, a commoner use

of metals, a system of writing already begun, and a more organized
government, these fresh people started a new civilization in Egypt; adopting
readily the art and skill of the earlier race, they formed by their union the
peculiar culture known as Egyptian, a type which lasted for four thousand
years. The same foundation of a type is seen in the bodily structure; the
early historical people had wider heads and more slender noses than the
prehistoric, but from 4000 B. C. down to Roman times the form shows no
change.
From this union of two able races came one of the finest peoples ever
seen, the Egyptians of the old kingdom, 4500—3500 B. C. Full of grand
conceptions, active, able, highly mechanical, and yet splendid artists, they
have left behind them the greatest masses of building, the most accurate
workmanship and exquisite sculptures in the grand pyramids and tombs of
their cemeteries. They perfected the art of organizing combined labor on the
immense public works. In all these respects no later age or country has
advanced beyond this early ability. The moral character and ideas are
preserved to us in the writings of these people; and we there read of the
ability, reserve, steadfastness, and kindliness which we see reflected in the
lifelike portraiture of that age.
After a partial decay about 3000 B. C. this civilization blossomed out
again nobly in the twelfth dynasty about 2600 B. C.; though the works of this
age hardly reach the high level of the earlier times, yet they are finer than
anything that followed them. At this period more contact with other
countries is seen; both Syria and the Mediterranean were known, though
imperfectly.
To this succeeded another decadence, sealed by the disaster of the
foreign invasion of the Hyksos. But this was thrown off by the rise of a
third age of brilliance—the eighteenth dynasty, 1500 B. C.—which, though
inferior to early times in its highest work, yet shines by the widespread of
art and luxury throughout the upper classes. Magnificence became
fashionable, and the lower classes contented themselves with most
barefaced imitations of costly wares. Foreign islands came closely in
contact with Egypt. The ships of the Syrian coast and Cyprus continually
traded to and fro, exchanging silver, copper, and precious stones for the
gold of Egypt. Greece also traded its fine pottery of the Mycenæan age for
the showy necklaces of gold and the rings and amulets with names of

Pharaohs. Egypt then dominated the shores of the western Mediterranean,
the plains of the Euphrates, and the fertile Soudan. But this power and
wealth led to disaster. Like Rome, later on, she could not resist the
temptation to live on plunder; heavy tribute of corn was exacted, large
numbers were employed in unproductive labor, and national disaster was
the natural consequence. Egypt never recovered the dominion or the
splendor that were hers in this age. Of this period some slight notions are
given us from literary remains in the Bible and Greek authors; but
archæology is, so far, our only practical guide, as in the earlier ages. The
great temples and monuments of the eighteenth-twentieth dynasties (1600–
1100 B. C.) bear hundreds of historical inscriptions, the tombs are covered
with scenes of private life, the burials and the ruins of towns furnish us with
all the objects of daily use. This age is one of the fullest and richest in all
history, and hardly any other is better known even in Greece or Italy. Yet all
this has been brought to light in the century, and the knowledge of the
foreign relations of Egypt is entirely the result of the last fifteen years.
The final thousand years of the civilization of Egypt is checkered with
many changes; sometimes independent, as in the ages of Shishak of Necho,
and of the Ptolemies; at other times a prey to Ethiopians, Persians, Greeks,
or Romans. Its arts and crafts show a constant decay, and there was but little
left to resist the influence of Greek taste and design, which ran a debased
course in the country. There was, however, a spread of manufactures and of
cheap luxuries into lower and lower classes; and the wealth of the country
accumulated under the beneficent rule of the earlier Ptolemies (300–200
B. C.).

The principal discoveries about these later ages have been in the papyri,
which have been largely found during the last twenty years. The details of
the government and life of the country in the Ptolemaic (305–30 B. C.) and
Roman (30 B. C.–640 A. D.) periods have been cleared up; and many prizes of
classical literature have also been recovered. The archæology of the Middle
Ages in Egypt has also been studied. Many of the Arabic buildings have
been recently cleaned and put in good condition, and the splendid collection
of manuscripts in Cairo has opened a view of the beautiful art of the
thirteenth-fifteenth centuries so closely akin to what was done in Europe at
the same time.

Egypt is, then, before all other lands, the country of archæology. A
continuous history of seven thousand years, with abundant remains of every
period to illustrate it, and a rich prehistoric age before that, give
completeness to the study and the fullest value to archæological research.

MESOPOTAMIA

The valley of the Euphrates might well rival that of the Nile if it were
scientifically explored, but unhappily all the excavation has been done
solely with a view to inscription and sculpture, and no proper record has
been made, nor have any towns been examined, the only work being in
palaces and temples.
The earliest study on the ground was by Rich (1818–20), who gathered
some few sculptures and formed an idea of Assyrian art. The French
Consul, Botta, excavated Khorsabad (founded 700 B. C.) in 1834–35, and
Layard excavated Nimrud in 1845–47; these were both Assyrian sites. The
older Babylonian civilization was touched at Erech by Loftus, in 1849–52;
and this age has attracted the most important excavations made since, at
Tello by Sarzec (1876–81), and at Nippur by Peters and Haynes, of
Philadelphia, during the last few years.
The cuneiform characters were absolutely unexplained until Grotefend,
in 1800, resolved several of them by taking inscriptions which he presumed
might contain names of Persian kings and comparing them alongside of the
known names; thus—without a single fixed point to start from—he tried a
series of hypotheses until he found one which fitted the facts. Bournouf (in
1836) and Lassen (1836–44) rectified and completed the alphabet. But the
cuneiform signs were used to write many diverse languages, as the Roman
alphabet is used at present; and the short Persian alphabet was only a
fraction of the great syllabary of six hundred signs used for Assyrian.
Rawlinson had independently made out the Persian alphabet, using the
Zend and Sanskrit for the language. He next, from the trilingual Behistun
inscription in Persian, Assyrian, and Vannic, resolved the long Assyrian
syllabary, using Hebrew for the language. Since then other more obscure
languages written in cuneiform have been worked with more or less
success; the most important is the Turanian language, used by the earlier

inhabitants of Babylonia before the Semitic invasion; this is recorded by
many syllabaries and dictionaries, and translations compiled by the literary
Semitic kings.
The general view of the civilization which has been obtained by these
labors of the century shows it to have been more important to the world
than any other. Cuneiform was the literary script of the world for at least six
thousand years, the only medium of writing from the Mediterranean to the
Indian Ocean. The Babylonian culture was almost certainly the source of
the oldest present civilization—that of China. And the arts were developed
probably even earlier than in Egypt. The first inhabitants were called
Sumirian (or river folk) in distinction from the Accadian (or highland)
people, who came from Elam down into the Euphrates valley, bringing with
them the use of writing. Their earliest writing was of figure symbols (like
the Egyptian and Hittite); but as in the valley clay tablets were the only
material for writing, the figures became gradually transformed into groups
of straight lines and spots impressed on the clay; hence the signs were
formalized into what we call cuneiform. The Semitic invaders were using
cuneiform characters by about 3000 B. C.
The early civilization was intensely religious, the main buildings being
the temples, which were placed on enormous piles of brick-work. The
sculpture was at a high level in the time of Naram-Sinn, about 3750 B. C.;
and yet below his ruins at Nippur there are no less than thirty-five feet
depth of earlier ruins, which must extend back to 6000 or 7000 B. C. In early
times stone implements were used alongside of copper and bronze, as we
find in Egypt 4000 B. C. Pottery was well made, and also reliefs in terra-
cotta. Personal ornaments of engraved gems and gold-work were common.
The main landmarks in the later time of this civilization are the Elamite
invasion of Kudur-nan-khundi (2280 B. C.) which upset the Semitic rulers,
and the Assyrian invasion of Tiglath-Adar (1270 B. C.), after which interest
centres in the Assyrian kingdom and its development of the Mesopotamian
culture which it borrowed. The main buildings of the Assyrian kings were
their enormous palaces, the mass of which was of unbaked bricks, faced
with alabaster slabs; such were the works of Assurnazir-pal (Nimrud, 880
B. C.), Sargon (Khorsabad, 710 B. C.), Sennacherib and Assurbani-pal
(Kouyunjik, 700 B. C.). The later, Assyrian, form of the civilization was to
the earlier Chaldean much what Rome was to Greece, a rather clumsy

borrower, who laboriously preserved the literature and art. Some of the
Assyrian sculpture of animals is, however, perhaps unsurpassed for vivid
action. The systematic libraries, containing copies of all the older literature
for general study, were most creditable, though the Assyrian himself
composed nothing better than chronicles. Nearly all that we possess of
Babylonian religion, and much of the history, is in the copies scrupulously
made from the ancient tablets by the Assyrian scribes, who noted every
defect in the original with critical fidelity.
The Mesopotamian civilization has left its mark on the modern world.
Its religion greatly influenced Hebrew, and thence Christian, thought, the
psalms, for instance, being a Babylonian form of piety. Its science fixed the
signs of the zodiac, the months of the year, the days of the week, and the
division of the circle in degrees, all of which are now universal. And its art,
carried by the Phœnicians, was copied by the Greeks and Etruscans, and
thus passed on into modern design.

SYRIA

The knowledge of Palestine was but slight, and of northern Syria
nothing to speak of, a century ago. Travellers with some scientific ability,
such as Robinson (1838 and 1852), De Saulcy (1853), and Van de Velde
(1854), greatly extended our view and led up to the splendid survey by the
Palestine Exploration Fund (1866 and on), which exhausted the surface
study of the land. The more archæological work of excavation was begun at
Jerusalem (1867–70), and resumed (1892–99) at Lachish, Jerusalem, etc.
The topographical results are all important, and leave nothing to be done
until excavation can be freely applied; and the small amount of digging yet
done has fixed the varieties of pottery back to 2000 B. C. and given some
early architecture. But the ruins of Syria, and indeed of Turkey in general,
are practically yet untouched. The discovery (1868) of the inscription of
Mesha, King of Moab (896 B. C.), opened a new prospect of research which
cannot yet be entered upon. In the north of Syria nothing has been done
except the German work at Singerli, from which came an Aramean
inscription of about 740 B. C. And in the south a large number of early

inscriptions of the Arabian dynasties, reaching back some centuries B. C.,
have been copied; but there, also, excavation is impossible.
The main new light from Syria has been on the Hittite power.
Burckhardt, in 1812, had noticed a new kind of hieroglyph at Hamath. After
several ineffective copies, Wright made casts of the stones in 1872. Several
other such inscriptions have been found, and from these and the Egyptian
and Assyrian references to the Hittites we now realize that they were a
northern people, with a great capital on the Euphrates, at Karkhemish, and
ruling over nearly all Syria and Asia Minor. Little has yet been fixed about
the writing; a few signs are read and some have passed into the Cypriote
alphabet. A striking proof of the spread of Babylonian culture is seen in the
tablets found in Egypt at Tel-el-Amarna in 1887, which show that all the
correspondence between Egypt and Syria in the fifteenth century B. C. was
carried on in cuneiform. These hundreds of letters give a vivid picture of
life in Syria at that early date.

GREECE

The revival of interest in Greek civilization was at first purely literary,
and remained so during two or three centuries. But during the last century
various travellers and residents abroad made collections which awoke an
interest in the art; and though most of these collectors were content with
merely showy sculpture, greatly restored and falsified for the market, yet
some—such as Hamilton—took a real archæological interest in the
unearthing and collecting of ancient art. The condition of study at the end of
the eighteenth century was that many private men of wealth had bought
large quantities of sculpture which was but little understood, and looked on
more from a decorative than a scientific point of view, while there were the
beginnings of a serious appreciation of it which had been just laid down by
Winckelmann.
The nineteenth century opened with a grand work of publishing the
principal treasures of classical art in England, which was finally issued in
1809 by Payne, Knight, and Townley; this marks the highest point of the
dilettante collecting spirit, which was soon eclipsed by truer knowledge.
Hitherto the best sculpture had hardly been known but at second hand

through Roman copies; a closer acquaintance began with the travels of
Dodwell, Gell, and Leake, all in the first decade of the century. The free
opening of the British Museum, in 1805, and the accumulation there of all
the best collections within the first quarter of the century, also served to
educate a public taste. The first struggle of scientific and artistic knowledge
against the dilettante spirit was over the Elgin marbles; by 1816 they were
accepted as the masterpieces which all later criticism has proved them to be.
The Æginetan and Phigaleian sculptures, brought to Munich and London,
helped also to show the nobility of early Greek art; so that the last two
generations have had a canon of taste to rely upon, the value of which
cannot be overestimated.
Following on this noble foundation, other collectors worked in Greece
and Asia Minor, and the British Museum profited by the labors of Burgon,
Fellows, and Woodhouse between 1840 and 1860. The diplomatically
supported work of Newton on the Mausoleum (1857–58), and Wood at
Ephesus (1863–75), filled out our knowledge of the middle period of Greek
art (350 B. C.). Comparatively little has been done since then by England,
but the activity of the Germans at Olympia has given us the only original
masterpiece that is known—the Hermes of Praxiteles (350 B. C.), and their
work at Pergamon revealed the great altar belonging to the later age (180
B. C.). The excavations at Athens (in 1886) have produced the impressive
statues dedicated to Athene about 520 B. C., which reveal the noble rise of
Attic sculpture. But attention during the last quarter-century has been
largely fixed upon the earlier ages. The discoveries of Schliemann at
Hissarlik (Troy, 1870–82), Mycenæ (1876), Orchomenos (1880–81), and
Tiryns (1884), opened a new world of thought and research. Though at first
bitterly attacked, it is now agreed that these discoveries show us the
civilization of Greece between 2000 and 1000 B. C. Lastly, during ten years
past Egypt has provided the solid chronology for prehistoric Greece by
discoveries of trade between the two countries.
We can now very briefly estimate the present position of our
knowledge as gained during the century. Setting aside the early foreign
pottery found in Egypt, which belongs probably to Greece or Italy at 5000
and 3000 B. C., we first touch a civilized city in the lowest town of Troy,
where metal was scarcely yet in use, which is certainly before 2000 and
probably about 3000 B. C. in date. Succeeding that is the finely built second

Troy, rich in gold vases and ornaments, which—though mistaken by
Schliemann for the Homeric Troy—must yet be long before that, probably
before 2000 B. C. After the burning of that come three other rebuildings
before we reach the town of the age of Mycenæ, about 1500 B. C. Of this,
which was in Greece the climax of the prehistoric civilization, there are the
splendid treasures found at Mycenæ, the magnificent domed tombs, the
abundance of fine jewelry and metal-work, of beautiful pottery and glazed
ornament. To this age belong the great palaces of Mycenæ, Tiryns, Athens,
and other hill fortresses, of which hardly more than the plans can now be
traced. And it is this civilization which traded eagerly with Egypt,
exchanging the valued manufactures of each country. This period was at its
full bloom from 1500–1200 B. C., and began to decay by 1100 B. C., this
dating being given by the contact with Egypt.
This natural decadence of art in Greece was hastened by the invasion of
the barbarous Dorians about 1000 B. C. Art, however, was by no means
extinguished, but only repressed by the troubles of the age; and Athens,
which was not conquered by the Dorians, was the main centre of the revival
of the arts. Other examples of such a history are familiar in Egypt (after the
Hyksos invasion) and in Italy (after the Lombards), where earlier abilities
revive and bloom afresh when vigorous invaders become united to an
artistic stock. After the centuries of warfare a quieter age allowed the
growth of fine arts again in the seventh century B. C., largely influenced by
Egyptian and Assyrian work at second hand, through the Greek settlements
in Cyprus and Egypt. By 600 B. C. definite types of sculpture were started,
and a course was begun which only ended in the fall of classical
civilization. The century before the Persian invasion, in 480 B. C., was one
of rapid development; and in sculpture and vase-painting we see that this
century carried forward the arts to technical perfection and the highest
power of expression. Immediately after the Persian wars came the supreme
works of Pheidias and Myron, most familiar in the Parthenon and the
Discobolus; and in vase-painting comes the reversal from vases drawn in
black on a red ground to the blocking out of the ground in black, leaving the
figure in red, thus giving far greater scope to the filling in of finely drawn
detail. The civilization of Athens was also at its height in this age, under
Pericles, and the minor arts received their most refined and perfect
treatment. After this comes nothing but ripening to decay. It must always be
remembered that we have but very few examples of original work of the

great artists. Nearly all the actual marbles preserved are copies made in later
times, which show little of the delicacy of the original; and the few original
marbles that remain are mostly of unknown subjects by unknown men. The
great work in Greek archæology during the last fifty years has been
comparing the records of ancient art (in Pliny, Pausanias, etc.) with the
remaining sculptures, critically assigning the various types of statues to
their celebrated originals, and thus forming some idea of the real history of
Greek art.
From these studies, full of detail and controversy, we may briefly sum
up the characteristics of the principal artists and their imitators. At about
440 B. C. Pheidias showed in the Parthenon the highest expression of divine
and mythic forms, in a simple and heroic style which was never equalled.
Half a century later Polykleitos followed a more human expression, using
motives (as in the Doryphoros), but yet portraying an abstract humanity. By
330 B. C. Praxiteles brought the expression of moods to his works, graceful,
animated, and with a full ripeness, as in the Hermes of Olympia, or the
Faun. Skopas, slightly later, marked his work by his great vigor and strong
personality. This was the second turning-point, when ripeness passed into
decay; and in Lysippos there is mere vivid naturalism and an impressionist
manner without much soul or thought, as in his Apoxyomenos, about 330
B. C. After this mere triviality and genre subjects are usual, portraiture is a
common aim, and dignity was vainly striven for in colossal size. The
glorification of showing dead and vanquished enemies is seen in the Dying
Gaul and figures of slain foes at Pergamon. Later on, about 180 B. C., we see
the violent, complicated, and straining action of the figures around the great
altar of Pergamon, which also appears in the groups of the Laocoon and
Farnese Bull. In the Græco-Roman age a conscious artificiality took the
place of life and expression, as we see in the Apollo Belvidere, the Venus di
Medici, and the Farnese Hercules. Art was saved in the first century A. D. by
the devotion of portraiture, which gave a sense of reality and conviction
which is entirely absent in the imaginative works. Lastly, a painstaking
study and admiration of earlier works led, under the wealthy patronage of
Hadrian (130 A. D.), to an eclectic revival which was wholly artificial, and
passed away within a generation. We have fixed on sculpture as the most
complete expression of Greek art; in other directions there is neither enough
material nor enough research to give us a connected view. Not a single
town, hardly a single house, in Greece has been excavated; there is no

consecutive knowledge of the ordinary products and objects of life; and
there is very little recorded of the discoveries of the tombs. The artistic
interest of the sculpture and architecture has starved other branches of
archæology, and for Greece more remains to be done than for some less
celebrated lands.

ITALY

The interest in Italy at the beginning of the nineteenth century was
mainly for the sake of its second-hand version of Greek art, and for the
architecture and painting of the Renaissance. On the contrary, now the
objects from Greece itself have far eclipsed the Italian copies, and the
interest lies in the early Italian civilization and its purely Roman
derivatives; while modern taste values the mediæval art of Italy far from the
bastard products of the florid age which followed. The first detailed studies
in Italy were those on Pompeii, especially by Gell (1817), which made that
debased style very popular, and paved the way for appreciation of better
work. The various isolated discoveries of Etruscan tombs were summed up
in the admirable work of Dennis (1848), which presented a general view of
that civilization which has not been superseded. The earlier Italic culture
has been examined in many places where accidental discoveries have
revealed it during the latter half of the nineteenth century, and especially in
the systematic work of Zannoni, at Bologna (1870–75), and of Orsi, lately,
in Sicily. The history of the city of Rome has been almost rewritten in the
last thirty years owing to the great changes of the new government; these
have been largely worked by Lanciani, and recorded by him and Middleton.
The view of Italian history at present begins in the Stone age, which has
been well studied, and has links with the later periods, as in the general use
of black pottery. The earliest metal objects are very simple blades of
daggers, found in graves, mingled with flint arrow-heads and knives. The
admirable Italian plan of preserving whole burials undisturbed in museums
enables us to see these graves complete in the Kircherian Museum. A
special branch of the early Bronze age life was the system of lake dwellings
(natural or artificially water girt), which abound in the northern Italian lakes
and over the plain of Lombardy. These towns (“terra mare”) are arranged on

a rectangular plan, and form the earliest stage of many of the present cities.
The full development of the Bronze age civilization seems to have been
later than in Greece, at about 800 B. C., to which belong the great discoveries
of tombs, weapons, and tools at Bologna, and the cemetery of Falerii.
Upon all the native Italic civilization came an entirely different
influence from the immigrant Etruscan. Traditionally coming from Asia
Minor, he brought art and religion which had no relation to the Italic. The
earliest Etruscan paintings are strongly northern in style, influenced by
north European feeling (Veii). But soon the Etruscan borrowed largely from
other races, from the Greek mainly, but also from Assyria and Egypt. Thus
the fascinating problem in Italy is to distinguish the various sources of
Italic, Etruscan, Græco-Etruscan, Oriental-Etruscan, and pure Greek, which
are found in all degrees of combination before Roman times, and which can
still be traced through the Roman age. The characteristics of Etruscan taste
are: (1) The extraneous objects and figures, such as rows of pendants to a
metal vase, monstrous heads standing out from a bowl, and statuettes placed
for handles; (2) in forms of vases and furniture, the combination of many
different parts and curves which never form a whole design; (3) and in
sculpture the large round head and staring eyes. In general, an air of clumsy
adaptation by a race deficient in originality. The glory of the Etruscan was
his engineering, which he handed as a legacy to Rome. Strange to say,
although thousands of Etruscan inscriptions are known, and many words are
translated, yet the language is sealed to us, and none of the many attempts
to read it has succeeded. The scientific study of Etruscan tombs has been
well followed lately, as shown in the Florence Museum, where a separate
room is devoted to each city.
In the south of Italy Greek art prevailed, and many of the finest works
belong to this civilization. The Greek in Italy had rather different ideals to
those of Greece; he started more from the level of Polykleitos and
Praxiteles than from the severe age; his favorite type is that of youth and
adolescence, never of maturity. The grace and feeling of such bronze statues
as the Hermes and so-called Sappho of Herculaneum are peculiar to
southern Italy. And when the Greek artist penetrated north and allied
himself with the mechanical skill of the Etruscan, such splendid work was
done as the Orator of Sanguineto.

Rome in the earlier centuries was an Italic town which came under
Etruscan influence as Tuscany was conquered. But from the age of foreign
conquest in the first century B. C., Greek art in a debased form ruled over all
else, and ran into utter degradation in the third century A. D. It was this art
that the power of Rome spread around the whole Mediterranean, from
Palmyra to Britain, and is the parent of most modern decoration. But in the
great reconstruction of the empire under Diocletian the debased Greek taste
was mostly shaken off, and Rome went back to the old Italic-Etruscan style
and motives. The statues have the round heads and staring eyes of old
Etruria; the taste for quaint accessories, such as lions supporting objects,
came back and passed into mediæval art, and the exaggerated, lengthy
forms of men and animals reappeared.
Of the Christian period De Rossi’s work in the catacombs has given a
firm base of facts for the third to the sixth century A. D., the actual tomb and
body of Saint Cecilia being the most striking result. The later Roman and
mediæval age in Italy is full of interest, but in that—as in the rest of
mediæval Europe—research has been mainly on architecture and objects
which are not the result of excavation.

INDIA

The Hindus have never been chronologists or historians, and their great
Sanskrit literature tells practically nothing about the rise of Buddhism, the
invasion of Alexander, or the spread of civilization in Indo-China. All
before the Islamic conquest in the tenth century A. D. is in a mist of Puranic
mythology. Here, then, more than in other countries, archæology has
restored the history, and done so entirely within the nineteenth century.
The existence of Sanskrit literature was revealed to the West by Sir
William Jones at the end of the last century, and this gave scope to Oriental
scholars, while antiquities only interested the collector. But serious
exploration was led by Prinsep, whose decipherment of the Asoka
inscriptions in 1837, which ranks with the achievements of Champollion
and Rawlinson, gave the key to a mass of inscriptions.

His assistant, Cunningham, excavated many sites and collected coins,
being head of the Archæological Survey from 1861 to 1885. Fergusson was
the historian of Indian architecture; Burgess has published the cave-temples
in west and south India; Sewell in Madras and Führer in the northwest have
excavated and explored, and a few native pundits have been educated to
such research. The government, in financial difficulty, has withdrawn from
the work, but the congress of Orientalists in 1897 resolved to establish an
Indian exploration fund.
Inscriptions abound in India, on copper plate, stone pillars, and native
rock. Those in Sanskrit, or modern vernaculars, are records of land grants or
local dynasties. The oldest—in two different alphabets (of Semitic origin)—
are the famous edicts of Asoka (third century B. C.), who has been called
The Buddhist Constantine. He placed these monuments of his power and
religion around his frontiers of northern India; but their meaning was
forgotten until Prinsep’s decipherment. The Hindus seem to have a coinage
of stamped silver plate before Alexander; but regular coinage begins in the
Bactrian kingdoms (200 B. C.–200 A. D.), with Greek and native inscriptions.
Since then the coinage is continuous, and invaluable for history. No stone
building or sculpture is older than Alexander (327 B. C.), or certainly earlier
than Asoka (264–233 B. C.). Greek influence is plain in the Punjab, but
native style is seen in the cave-temples. The richest results have been from
the mounds, some of which are ruins of forts or palaces, but the more
important are the stupas, lofty domes erected two to one thousand years ago
to enshrine Buddhist relics. These domes are surrounded with sculptured
reliefs of scenes in the life of Buddha, and are often dated by inscriptions.
From one lately opened the Buddha relic has been sent to the King of Siam,
the only Buddhist king. Much has been done by the government in
publishing and providing casts and photographs; but India yet needs a
scientific archæologist to record details with the accuracy demanded by
modern research.

AMERICA

Archæological work in the United States and in Central America was
begun by Squier about the middle of the century, and the attention thus

drawn to the subject has borne fruit in the more accurate and scientific
explorations connected with the surveying and geological departments, and,
above all, those of the Smithsonian Bureau of Ethnology. The names of
Whitney, Wright, Cyrus Thomas, Holmes, Fowke, Mindeleff, and others,
will be familiar to all American readers by their work of the last twenty
years, and need no introducing here.
The earliest remains of man in America—or perhaps in the world—are
those beneath the great lava beds of California; since those were deposited
the rivers have cut their beds through two thousand to four thousand feet of
lava rock, implying an erosion during tens, or perhaps hundreds, of
thousands of years. But little can be assigned, however, with any certainty
to a date before the Christian era, though mounds of refuse on both ocean
shores may probably belong to an age before any human history.
The most important studies have been those on the highest civilization
of the continent, that of Central America. The destroying Spaniards
preserved but little of native record, except incidentally, and the first
collector of Aztec manuscripts was Benaduci (1736), of whose treasures but
an eighth survived his imprisonments and persecutions, one of the greatest
disasters to history. The first great publication of manuscripts was the
magnificent work of Lord Kingsborough (1830); and almost at the same
time appeared Prescott’s history. Though the later researches have shown
that the land was divided into many small kingdoms, rather than under one
power, as Prescott supposed, yet his account of the calendar and chronology
of the Aztecs has been verified and added to, and far more has been done in
reading the manuscripts than he supposed possible. Aubin, after years of
work in Mexico, brought to Europe manuscripts of an entirely new kind,
showing a fully developed system of phonetic writing, which he has largely
deciphered with success, having analyzed over one hundred syllabic values
correctly.
One of the most complete studies has been that of the Mayan Quiché
peoples, and especially of the Mayans of Yucatan. In 1864 Landa’s work on
Yucatan (written 1566) was rediscovered, and the account of the calendar
has sufficed to enable Goodman to discover the meaning of a very large
number of signs (1897); these enable the numerical documents to be
translated, and show that a period of as much as eight thousand years was
dealt with by the Mayans, perhaps belonging to mythical ages. The

alphabetic signs of Landa have proved useless so far, and Goodman even
disbelieves in any record except that of numbers. Seler has shown the
identical origin of the signs used by Aztecs and Mayans for the days and
months. Little had been done to make known these remains until the recent
explorations, casts, and publications of Maudsley, who has worked
magnificently for seventeen years at Copan, Palenque, and Chichen-Itza;
these, however, are but three of innumerable cities of Guatemala and
Yucatan that need exploration.
In New Mexico the many ruins from the Colorado to the Rio Grande
have been proved to resemble those of the modern Pueblo Indians, and to
have none of the characteristics of Central American architecture; there are
no sculptures, and the rock inscriptions are too primitive to be interpreted.
Nothing points to an Aztec occupation, and probably the ancestors of the
present people were the builders.
The innumerable earthworks of the Mississippi valley were formerly
supposed to belong to some vanished race. And the view that they were
connected with the Central American civilization is favored by the pyramid
mound, which was hardly known otherwise, and by the excellence of the
minor sculpture. But there are great differences between the two
civilizations. The mound-builders were far inferior in metal-working, and
their burial customs are peculiar. The use of materials from both east and
west coasts shows an extensive commerce. The best summing up of the
researches is that by Prof. Cyrus Thomas, after his extensive excavations.
He concludes that the remains of the mound-builders show no great
antiquity; that they were formed by tribes like the existing Indians; that the
builders were of the same culture as were the Indians when discovered; that
such mounds continued to be made and used for burial during the European
period, and that the principal builders were the Cherokees.
It will be seen now how totally our view of man’s history has been
changed by the study of archæology, and how fundamentally this science
affects our ideas of the past and our expectations for the future of our race.
The main outlines have been dimly seen; but in every country the greater
part yet remains to be done, and in Turkey, Persia, and China most
important civilizations are as yet quite untouched by exploration. The new
century will no doubt see a harvest from these lands; and it is to be hoped
that what yet remains in the safe keeping of the earth may be found by able

men, who will preserve it for instruction and enable posterity to trace the
fortunes of our species.
[India and America are here treated with the assistance of Mr. J. S.
Cotton and Mr. D. MacIver.]

W. M. Flinders Petrie.

ASTRONOMY

I n struck
looking back over a century’s work in the oldest of the sciences, one is
not only by the enormous advance that has been made in those
branches of the science dealing with the motions of the heavenly bodies
which were cultivated at least eight thousand years ago by early dwellers in
the valleys of the Nile, Tigris, and Euphrates, but with the fact that during
the century that has just passed away a perfectly new science of astronomy
arose. By annexing physics and chemistry astronomers now study the
motions of the particles of which all celestial bodies are composed; a new
molecular astronomy has now been firmly established side by side with the
old molar astronomy which formerly alone occupied the thoughts of star-
gazers.

Along this new line our knowledge has advanced by leaps and bounds,
and the results already obtained in expanding and perfecting man’s views of
nature in all her beauty and immensity are second to none which have been
garnered during the last hundred years.

THE POSITION AT THE BEGINNING OF THE
CENTURY

It may be well before attempting to obtain a glimpse of recent progress
that we should try to grasp the state of the science at the time when the
nineteenth century was about to dawn, and this, perhaps, can be best
accomplished by seeing what men were working at this period, at which the
greatest activity was to be found in Germany; there was no permanent
observatory in the southern hemisphere or in the United States.

First and foremost among the workers—he has, in fact, been described
as “the greatest of modern astronomers”—was William Herschel, a German
domiciled in England. In the year 1773 he hired a telescope, and with this
small instrument he obtained his first glimpses of the rich fields of
exploration open in the skies. From that time onward he had one fixed
purpose in his mind, which was to obtain as intimate knowledge as possible
of the construction of the heavens.
To do this, of course, great optical power was necessary, and such was
his energy that, as large instruments were not to be obtained at any price, he
set to work and made them himself.
Herschel presented the beginning of the nineteenth century not only
with a definite idea of the constitution of the stellar system, based on a
connected body of facts and deductions from facts, as gleaned through his
telescopes, but observations without number in many fields. He discovered
a new planet, Uranus, and several satellites of the planets; published
catalogues of nebulæ; established the gravitational bond between many
“double stars,” and carried on observations of the sun, then supposed to be a
habitable globe. What Herschel did for observational astronomy and
deductions therefrom, Laplace did for the furtherance of our knowledge
concerning the exact motions of the bodies comprising the solar system.
Newton had long before announced that gravitation was universal, and
Laplace brought together investigations undertaken to determine the
validity of this law. These were given to the world in his wonderful book on
Celestial Mechanics, the first volumes of which appeared in 1799.
A survey of the work of these two great astronomers gives one an idea
of what was going on in observational and mathematical astronomy at the
beginning of the century.
The study was now destined to make rapid strides, as not only were
new optical instruments—some designed for special purposes—introduced,
new mathematical processes applied, fresh fields for research opened up,
but the number of workers was considerably augmented by the increased
means available; so much so, indeed, that the first astronomical periodical
was founded by Von Zach in 1800 to facilitate intercommunications
between the observers.

The first evening of the nineteenth century (January 1, 1801) augured
well for progress. It had long been thought that all the members of the solar
system had not as yet been discovered, and there was a very notable gap
between the planets Mars and Jupiter, indicated by Bode’s law. Observers
were organized to make a thorough search for the missing planet, portions
of the sky being divided between them for minute examination. It fell to the
Italian observer, Piazzi, to discover a small body which was moving in an
orbit between these two planets on the date named. The century thus began
with a sensation, and because the new body, which was named “Ceres,” was
not of sufficient size to be accepted as the “missing planet,” the idea was
suggested that perhaps it was a fragment of a larger planet that had been
blown to pieces in the past.
An opportunity here arose for mathematical astronomy to come to the
help of the observer, for Ceres soon was lost in the solar rays, and in order
to rediscover it, after it had passed conjunction, an approximate knowledge
of its path and future position was necessary.
With the then existing methods of computation of orbits it was
imperative to have numerous measured positions to use as data for the
calculation. The scanty data available in the case of Ceres were not
sufficient for the application of the method. The occasion discovered a man,
one of the greatest mathematicians of the nineteenth century, Karl Frederick
Gauss, who, although only twenty-five years of age, undertook the solution
of the problem by employing a system which he had devised, known as “the
method of least squares,” which enabled him to obtain a most probable
result from a given set of observations.
This, with a more general method of orbit computation, also elaborated
by himself, was sufficient to enable him to calculate future positions of
Ceres, and on the anniversary of the original discovery, Olbers, another
great pioneer in orbit calculations, found the planet in very nearly the
position assigned by Gauss. So great was the curiosity regarding the other
portions of the planet, which was supposed to have been shattered, that
numerous observers at once commenced to search after other fragments.
These were the actualities of 1801 and thereabouts; but the seed of
much future work was sown. Kant and Laplace had already occupied
themselves with theories as to the world formation, and spectrum analysis

as applied to the heavenly bodies may be said to have been started by
Wollaston’s observations of dark lines in the solar spectrum in 1802.
Fraunhofer was then a boy at school. In the same year the first photographic
prints were produced by Wedgewood and Davy.

OBSERVATORIES

It has been stated that at the beginning of the century there were no
permanent observatories either in the southern hemisphere or in the United
States. The end of the century finds us with two hundred observatories all
told, of which fourteen are south of the equator and forty-seven in the
United States, among which latter are the best-equipped and most active in
the world.
The observatory of Parramatta was the first established (1821) in the
southern hemisphere. This was followed by that at the Cape of Good Hope
in 1829. Of the more modern southern observatories from which the best
work has come we may mention Cordova, the seat of Gould’s important
investigations, established in 1868, and Arequipa, a dependency of Harvard,
whence the spectra of the southern stars have been secured, erected still
more recently (1881).
I believe, but I do not know, that the large number of American
observatories have radiated from Cincinnati, where, in consequence of
eloquent appeals, both by voice and pen, from Mitchell, then professor of
astronomy, an observatory was commenced in 1845. There can be no doubt
that at the present moment, with the numerous well-equipped and active
observatories, and the careful and thorough teaching established side by
side with them, which enables numberless students to use the various
instruments, the United States, in matters astronomical, fills the position
occupied by Germany at the beginning of the century.
In Europe special observatories have been established at Meudon,
Kensington, and Potsdam, so that new astrophysical inquiries may be
undertaken without interfering with the prosecution or extension of the
important meridional work carried on at Paris, Greenwich, and Berlin. A

large proportion of the observations made by the Lick and Yerkes
observatories in the United States has been astrophysical.
One of the special inquiries committed to the charge of the Solar
Physics Observatory at Kensington at its establishment by the British
government had relation to the possibility of running home meteorological
changes on the earth, especially those followed by drought and famines in
various parts of the empire, to the varying changes in the sun indicated by
the ebb and flow of spots on its surface. With this end in view observations
of the sun were commenced in India and the Mauritius to supplement those
taken at Greenwich. At the same time other daily observations of sun spots
by a different method were commenced at Kensington.
This kind of work was at first considered ideally useless; we shall see
later on what has become of it.

IMPROVEMENTS IN TELESCOPES

The progress in astronomical science throughout the nineteenth century
has naturally to a great extent depended upon the advances made both in the
optics of the telescope and the way in which they are mounted, either with
circles to record exact times and positions, or made to move so as to keep a
star or other celestial objects in the field of view while under observation.
The perfection of definition and the magnitude of the lenses employed in
the modern instrument have been responsible for many important
discoveries.
Ever since the telescope was invented—Galileo’s lens was smaller than
those used in spectacles—men’s minds have been concentrated on
producing instruments of larger and larger size to fathom the cosmos to its
innermost depths.
At the beginning of the century we were, as we have seen already, in
possession of reflectors of large dimensions; Herschel’s four-foot mirror,
the instrument he was using in 1801, which had a focal length of forty feet,
was capable of being employed with high magnifying powers; and it was
the judicious use of these, on occasions when the finest of weather
prevailed, that enabled him to enrich so extensively our knowledge of the

stellar and planetary systems. For the ordinary work of astronomy, however,
especially when circles are used, refractors are the more suitable
instruments. This form suffers less from the vicissitudes of weather and
temperature, and is, therefore, more suited where exact measurements are
required.
Towards the end of the eighteenth century a Swiss artisan, Pierre
Guinard, after many years of patient labor, succeeded in producing pure
disks of flint glass as large as six inches in diameter. The modern refracting
telescope thus became possible.
In 1804 there was started at Munich the famous optical and mechanical
institute, which soon made its presence felt in the astronomical world.
Reforms in instrument making were soon taken in hand, and under the
leadership of the great German astronomer, Bessel, great strides were made
in instruments of precision. Fraunhofer, who had been silently working
away at the theory of lenses, and making various experiments in the
manufacture of glass, was joined, in 1805, by Guinard. In 1809 Troughton
invented a new method of graduating circles, according to Airy the greatest
improvement ever achieved in the art of instrument making.
In 1824 Fraunhofer successfully completed and perfected an object-
glass of 9.9 inches in diameter for the Dorpat Observatory. This objective
might literally have been called a “giant,” for nothing approaching it in size
had been previously made.
England, which was at one time the exclusive seat of the manufacture
of refracting telescopes, was now completely outstripped by both Germany
and France, and for this we had to thank “the short-sighted policy of the
government, which had placed an exorbitant duty on the manufacture of
flint glass.” In 1833 the Dorpat refractor was eclipsed by one of fifteen
inches aperture made for the Pulkowa Observatory by Merz & Mähler,
Fraunhofer’s successors, who about ten years later supplied a similar
instrument to Harvard College. At that time Lord Rosse emulated with
success the efforts of Herschel and rehabilitated the reflector by producing a
metallic mirror of six-foot aperture and fifty-four-foot focal length which he
mounted at Parsonstown. The speculum weighed no less than four tons. To
mount this immense mass efficiently and safely was a work of no light
nature, but he successfully accomplished it, and eventually both mirror and

the telescope, which weighed now altogether fourteen tons, were so well
counterpoised that they could be easily moved in a limited direction by
means of a windlass worked by two men. The perfection of the “seeing”
qualities of this instrument and its enormous light-grasping powers were
particularly striking, and observational astronomy was considerably
enriched by the discoveries made with it.
Speculum metal was not destined to stay; ten years later (1857) the
genius of Léon Foucault introduced glass mirrors with a thin coating of
silver deposited chemically, and these have now universally superseded the
metallic ones.
The long supremacy of Germany in the matter of refractors was broken
down ultimately by the famous English optician and engineer, Thomas
Cooke, of York. His first considerable instrument, one of seven inches
aperture, was finished in 1851; and in 1865, a year before his lamented
death, he completed the first of our present giant refractors, one of twenty-
five inches aperture, for Mr. Newall, of Gateshead. In consequence of the
success of Cooke’s achievement other large refractors were soon
undertaken.
Alvan Clarke, the famous optician of Cambridgeport, Massachusetts, at
once commenced a twenty-six-inch for the Washington Observatory. The
next was one of twenty-seven inches, made by Grubb for the Vienna
Observatory. Object-glasses now grew inch by inch in size, depending on
the increased dimensions of disks that could be satisfactorily cast. Gautier,
of Paris, completed a twenty-nine-and-a-half-inch for the Nice Observatory,
while Alvan Clarke made an objective of thirty inches for Pulkowa. In 1877
the latter successfully completed the mounting of an objective of thirty-six
inches for the Lick Observatory, but this immense lens was only achieved
after a great number of failures. Even this large object-glass was surpassed
in size by the completion in 1892 of the forty-inch which he made for the
Yerkes Observatory, and by that made by Gautier for the Paris Exhibition of
1900.
So much, then, for the largest refractors. In recent years, since the
introduction of the silver on glass mirrors, with their stability of figure and
brilliant surface, which can be easily renewed, reflectors of large apertures
are again being produced. The first of these was one of thirty-six inches

aperture made by Calver for Dr. Common, who demonstrated its fine
qualities and his own skill by the beautiful photographs of the nebula of
Orion he was enabled to secure with it. Dr. Common himself has since
turned his attention to the making and silvering of large mirrors of this kind,
and the largest he has actually completed and mounted equatorially is one
with a diameter of five feet. Another of thirty-six inches aperture is in use at
the Solar Physics Observatory at Kensington.
The progress of depositing silver on glass has led of late years to
important developments in which plane mirrors are used. Foucault was the
first to utilize such mirrors in his “siderostat,” in which such a mirror is
made to move in front of a horizontal fixed telescope, which may be of any
focal length, and no expensive dome or rising floor is required. The plane
mirror of the siderostat in the Paris Exhibition telescope is six feet in
diameter.
A variation of this instrument is the cœlostat more recently advocated
by Lippmann. The Coudé equatorial mounting also depends upon the use of
plane mirrors; with such a telescope the observer is at rest at a fixed eye-
piece or camera in a room which may be kept at any temperature.
Now that in astronomical work eye observations are indispensably
supplemented by the employment of photography, an important
modification of the refracting telescope has become necessary; this was first
suggested by Rutherfurd.
The ordinary achromatic object-glass consists, as a rule, of two lenses,
one made of flint and the other of crown glass; but in this form the
photographic rays are not brought to the same focus as the visual rays. This,
however, can be achieved by employing three lenses instead of two, each of
different kinds of glass. The most modern improvement in the telescope is
due to Mr. Dennis Taylor, of Cooke & Sons, and to Dr. Schott and Professor
Abbe, whose researches in the manufacture of old and new varieties of
optical glass have rendered Mr. Taylor’s results feasible. By the Taylor lens
outstanding color is abolished, all the rays being brought absolutely to the
same focus; such lenses can therefore be used either for visual observations
or for photography for spectroscopy.

SPECTROSCOPIC ASTRONOMY

The branch of physics which at the present day has assumed such
mighty and far-reaching proportions in astronomical work is that dealing
with spectrum analysis, which, although suggested as early as the time of
Kepler, did not receive any impetus as regards its application to celestial
bodies until the beginning of the present century at the hands of Wollaston
and Fraunhofer. Then, however, it still lacked the chemical touch supplied
afterwards by Kirchhoff and Bunsen. They showed us that the spectrum
observed when the light from any heated body is passed through a prism is
an index to the chemical composition of the light source; the constitution of
a vapor when in a condition to absorb light can be determined by an
extension of the same principle, first demonstrated by Stokes, Angström,
and Balfour Stewart, when the century was about half completed.
The first celestial body towards which the spectroscope was turned was
our central luminary, the sun.
Wollaston first discovered that its spectrum was crossed by a few dark
lines; we learned next from Fraunhofer, who in 1814 worked with
instruments of greater power, that the solar spectrum was crossed not only
by a few dark lines, but by some hundreds. Not content with examining the
light of the sun, Fraunhofer turned his instrument towards the stars, the light
of which he also examined, so that he may be justly called the inventor of
stellar spectrum analysis. It is not to the credit of modern science that from
this time forward spectrum analysis did not become a recognized branch of
scientific inquiry, but, as a matter of fact, Fraunhofer’s observations were
buried in oblivion for nearly half a century. The importance of them was not
recognized till the origin of the dark lines, both in sun and stars, had been
explained by Stokes and others, as before stated. The lines in the solar
spectrum were mapped with great diligence by Kirchhoff in 1861 and 1862,
and later by Angström and Thalen, and this was done side by side with
chemical work in the laboratory. The chemistry of the sun was thus to a
great extent revealed; it was no longer a habitable globe, but one with its
visible boundary at a fierce heat, surrounded by an atmosphere of metallic
vapors, chief among them iron, also in a state of incandescence. To these
metallic vapors Angström added hydrogen shortly afterwards.

Here, then, was established a firm link between the heavens and the
earth; the first step to the problem of the chemistry of space had been taken.
It was only natural that as advances were made the instrumental
equipment should keep pace with them. Spectroscopes were built on a
larger scale; more prisms, which meant greater dispersion, were employed
to render the measurements of the lines in spectra more accurate. The
growth of our knowledge especially necessitated the making of maps of the
lines in the solar spectrum, and in the spectra of the chemical elements
which had been compared with it on a natural scale. This was done by
Angström, who utilized for this purpose the diffraction grating invented by
Fraunhofer, and defined the position of all lines in spectra by their “wave
lengths,” in ten-millionths of a millimetre or “tenth-metres.”
In 1862 Rutherfurd extended Fraunhofer’s work on the stars by a first
attempt at classification. Two years later Huggins and Miller produced
maps of the spectra of some stars. Donati demonstrated that comets gave
radiation spectra, and Huggins did the same for nebulæ.
By these observations comets and nebulæ were shown to be
spectroscopically different from stars, which at that time were studied by
their dark lines only.
Chiefly by the labors of Pickering, the energetic head of the Harvard
Observatory, science has been enriched during the later years by
observations of thousands of stellar spectra, the study of which has brought
about the most marvellous advance in our knowledge.
These priceless data have enabled us now to classify the stars not only
by their brightness, or their color, but by their chemistry.
Next to be chronicled is the application of the so-called Doppler-Fizeau
principle, which teaches us that when a light source is approaching or
receding from us the light waves are crushed together or drawn out, so that
the wave length is changed. The amount of change gives us the velocity of
approach or recess, so that the rate of movement of stars towards or from
the earth, or the up-rush or down-rush of the solar vapors on the sun’s disk
can be accurately determined. A further utilization of this principle is found
when the stars are so close together that they appear as one if the plane of
motion passes near the earth. A line common to the spectra of both stars will

appear double twice in each revolution, when the motion to or from the
earth, or, as it is termed, “in the line of sight,” is greatest. “Spectroscopic
doubles,” as these stars are called, yield up many of their secrets which
otherwise would elude us. Their time of revolution, the size of the orbit, and
the combined mass can be determined.
To return from the stars to the sun.
By the device of throwing an image of the sun on the slit of the
spectroscope the spectra of solar spots have been studied from 1866
onward, and a little later the brighter portions of the sun’s outer envelopes,
revealed till then only during eclipses, were brought within our ken
spectroscopically, so that they are now studied every day.

CELESTIAL PHOTOGRAPHY

Wedgewood and Davy, in 1802, made prints on paper by means of
silver salts, but it was not until 1830 that Niepce and Daguerre founded
photography, which Arago, in an address to the French Chamber, at once
suggested might subsequently be used to record the positions of stars.
In 1839 we find Sir John Herschel carrying out a series of experiments
so important for our correct knowledge of the sequence of steps in the early
stages of photography that I have no hesitation in quoting from one of
Herschel’s manuscripts relating to a deposit on a glass plate of “muriate”
[chloride] of silver from a mixed solution of the nitrate with common salt.
The manuscript states: “After forty-eight hours [the chloride] had formed a
film firm enough to bear draining the water off very slowly by a siphon.
Having dried it, I found that it was very little affected by light, and by
washing it with nitrate of silver, weak, and drying it, it became highly
sensitive. In this state I took a camera picture of the telescope on it.”
The original of the above-mentioned photograph, the first photograph
ever taken on glass, is now in the science collection at the Victoria and
Albert Museum, South Kensington.
In the early days of photography colored glasses were first used to
investigate the action of different colors on the photographic plate. Sir John

Herschel was among the first to propose that such investigations should be
made direct with a spectrum, and he, like Dr. J. W. Draper, stated that he
had found a new kind of light beyond the blue end of the spectrum, as the
photographic plate showed a portion of the spectrum there which was not
visible to the eye. Advance followed advance, and in 1842 Becquerel
photographed the whole solar spectrum, in colors, with nearly all the lines
registered by the hand and eye of Fraunhofer, not only the blue end, but the
complete spectrum, from Draper’s “latent light,” as he called the ultra-violet
rays, to the extreme red end.
The first photograph of a celestial object was one of the moon, secured
by Dr. J. W. Draper in 1840; we had to wait till 1845, so far as I know,
before a daguerreotype was taken of the sun; this was done by Foucault and
Fizeau, while the first photograph of a star—Vega—was taken at Harvard in
1850. After the introduction of the wet-collodion process regular
photography of the sun’s surface was commenced, at Sir John Herschel’s
recommendation, at Kew in 1858, and the total solar eclipse of 1860 was
made memorable by the photographs of De La Rue, who before that time
had secured most admirable photographs of the moon, as also had
Rutherfurd.
Photography now began to pay the debt she owed to spectrum analysis.
The first laboratory photograph of the spectra of the chemical elements
was taken by Dr. W. A. Miller in 1862.
Rutherfurd was the first to secure a photograph of the solar spectrum
with considerable dispersion by means of prisms.
In 1863 Mascart undertook a complete photographic investigation of
the ultra-violet portion of the solar spectrum, a work of no mean magnitude.
He, however, did not employ a train of prisms for producing the spectrum,
but a diffraction grating, using the light reflected from the first surface. The
first photograph of the spectrum of a star was secured by Henry Draper, the
son of Dr. J. W. Draper, one of the pioneers in photography in 1872.
It was not till the introduction of dry plates in 1876 that the
photography of the fainter celestial objects or of their spectra was possible,
as a long exposure was naturally required. Stellar spectra were
photographed by Huggins in 1879, and in the next year Draper

photographed the nebula of Orion. As the dry plates became more rapid,
and as longer exposures were employed, revelation followed revelation; the
nebulæ as seen by the naked eye, and even some stars, were found by the
Henrys, Roberts, Max Wolf, Barnard, and others, to be but the brighter
kernels of large nebulous patches.
This new application of photography, depending upon long exposures
(the longest one I know of has extended to forty hours), had an important
reflex action on the mechanical parts of the telescope; it was not only
necessary to keep the faintest star exactly on the same part of the plate
during the whole of the exposure, but night after night the stellar image
must be brought on to the same part of the plate so that the exposure might
be continued.
A system of electric control of the going of the driving-clock of the
telescope by means of a sidereal clock was introduced, the simplest one
being designed by Russell, of Sydney; a most elaborate one by Grubb, of
Dublin.
Another application of the method of long exposures has been the
discovery of minor planets by the trails impressed by their motion among
the stars on the photographic plates on which the images of both are
impressed.
A complete spectroscopic survey of the stars by means of photography
was commenced in 1886 at Harvard College, as a memorial to Draper, who
died while he was laboring diligently and successfully in securing advances
in astrophysical inquiries. To carry on this work at Harvard, Professor
Pickering wisely reverted to the method first employed by Fraunhofer, and
utilized by Respighi and another in 1871, of placing prisms in front of the
object-glass.
In the photographing of stellar spectra by means of objective prisms,
the driving-clock of the telescope must not go exactly at sidereal rate, but at
certain speeds depending on the brightness and position of the star under
examination.
This is necessary because the image of the spectrum of a star on the
photograph is only a thin line in which it is impossible to see the spectral
lines; the spectrum must be broadened, and this is accomplished by making

the star image “trail” to a certain degree on the plate. This trailing is
accomplished by means of the clock, the rate of which is made to vary. In
this way the trail of a spectrum of a star on the photographic plate is always
obtained of the same width, while the density of the image is made fairly
constant by increasing the rate for bright stars and decreasing it for fainter
ones. In this way spectra of the brighter stars rivalling in perfection and
detail those obtained of the spectrum of the sun itself thirty years ago have
been obtained. Such photographs have rendered a minute chemical
classification of the stars possible.
One of the most interesting applications of photography to spectrum
analysis during the latter part of the century has been the utilization by
Messrs. Deslandres and Hale of a suggestion made by Janssen, that by
employing photography images of the sun and its surroundings can be
obtained in light on one wave length. In this way we can study the
distribution of any one of the chemical constituents of the sun separately,
and note its behavior, not only on the sun itself, but in the atmosphere
which enfolds the disk.
It is strange that, in spite of the suggestions of Faye, and others after
him, one of the great advantages of the employment of photography in
astronomical work, namely, the abolition of “personal equation,” has so far
been almost entirely neglected. What “personal equation” is can be perhaps
illustrated by considering an observer who is observing the transit of a star
over the wires in a transit instrument.
His object is to note the exact time, to a fraction of a second, when a
star passes each wire; and this is done by listening to the beats of a clock
near at hand and estimating the fractions. Some observers constantly note
the time either a little in advance or a little later than the actual time, and
this small distance between the observer and the true times is more or less
constant for each observer. This difference has to be taken into account for
every observation. Even the use of the chronograph in transit work, by
which the observation is electrically recorded, does not entirely eliminate
the error. The photographic method of transit work has been experimented
on, but, so far as I know, it has not yet been used at more than one or two
observatories. It will doubtless eventually rid us of “personal equation”
entirely, for the star image may be photographed and the time recorded by
the same current of electricity.

At the end of the century we could almost say that except in relation to
the work of the meridional observatories, photographic methods of
recording observations had become exclusively used. One of the cases in
which its utility is most in evidence is in the matter of eclipse observations.
Spectra of the sun’s surroundings containing a thousand lines are taken in a
second of time, thus replacing five or six doubtful eye observations by
wealth of results which have enabled the recent vast progress to be secured.

CATALOGUES

Catalogues of the stars were among the first scientific records started
by man, and so long as only the naked eye was used the work was not
difficult, as only approximate positions were attempted, even by
Hipparchus; but long before the eighteenth century dawned the problem
was entirely changed by the invention of the telescope and by the provision
of accurately divided circles; not only could better positions be recorded,
but the number of stars to be catalogued was enormously increased, and,
furthermore, other objects, nebulæ, presented themselves in considerable
numbers.
In 1801 the star catalogues chiefly relied on were those of Lacaille,
containing about three thousand stars scattered over the whole heavens.
Maskelyne, who was then Astronomer Royal, had published in 1790 a
catalogue of thirty-six fundamental stars, chiefly for the purposes of
navigation. The first great catalogue of the century was the Fundamenta
Astronomiae of Bessel, produced in 1818. This contained three thousand
two hundred and twenty-two stars. The Bonn Durchmüsterung, with its
catalogue of three hundred and twenty-four thousand one hundred and
ninety-eight stars in the northern hemisphere, and the corresponding atlas
published in 1857–63, was the next memorable achievement in this
direction. For it we have to thank Bessel and Argelander and a perfect
system of work.
Another monumental catalogue dealing with the stars in the southern
heavens has been that of the southern stars observed by Gould (1866).
While the century was closing, another catalogue, far more stupendous than

anything which could be conceived possible a few years ago, was steadily
being compiled. This we owe to the far-sightedness and energy of Admiral
Mouchez, a late director of the Paris Observatory. The work was
commenced in 1892.
The whole heavens, north and south alike, have been divided into
zones, and the chief observatories on the earth’s surface are busy night after
night in taking photographs of that part intrusted to them. The whole
heavens are thus being made to write their autobiography, and the total gain
to the astronomy of the future of this most priceless record can perhaps be
scarcely grasped as yet, although the advantage of being able at any point of
future time to see on a photographic plate what the heavens are telling now
is sufficiently obvious.
Catalogues of the stars have, of course, led to other minor catalogues of
various classes of stars, binary, variable, and the like. In the later years
catalogues of stars according to their spectra have enriched science.
The first extensive catalogue of stellar spectra was published by Vogel.
It dealt with four thousand and fifty-one stars, and appeared in 1883; it has
since been followed by the Draper catalogue, based upon photographs of
the spectra, which contains a much larger number. With regard to nebulæ,
Herschel published his third catalogue in 1802. The last catalogue of this
nature is by Dreyer (1888), and contains seven thousand eight hundred and
forty of these objects. In the time of Tycho they could be counted on the
fingers of one hand.

INVESTIGATIONS OF SOME IMPORTANT
ASTRONOMICAL CONSTANTS

The nineteenth century was fruitful in the determination of many
numerical values which are all important in enabling us to determine the
distance and masses of the heavenly bodies, thereby giving us a firm grasp
not only of the dimensions of our own system, but of those scattered in the
celestial spaces.
To take the distances first. We must begin with the exact measure of the
earth; for this we must measure the exact length of an arc of meridian or of

parallel—that is, a stretch of the earth’s surface lying north and south or
east and west, between places of which the latitudes are accurately known
in the former case, and the longitude in the latter. In either case we can
determine the number of miles which go to a degree. Beginning at the
opening of the nineteenth century with an arc of meridian of two degrees
measured by Gauss, from Göttingen to Altona, the arcs of meridian grew
longer as the century grew older, till, at the close, the measurement of an arc
of meridian from the Cape to Cairo, embracing something like sixty-eight
degrees of latitude, was mooted.
The measurements of arcs of parallel have been developed by the rapid
extension of telegraphic communications, which now permit the longitude
of the terminal stations to be determined with the greatest accuracy.
Thanks to this work, we now have the size of our planet to a few miles.
The polar diameter is 41,709,790 feet, but the equator is not a circle: the
equatorial diameter from longitude 8 degrees 15 minutes west to longitude
188 degrees 15 minutes west is 41,853,258 feet; that at right angles to it is
41,850,210 feet—that is, some thousand yards shorter. The earth, then, is
shaped like an orange slightly squeezed.
Knowing the earth’s diameter, we can obtain the sun’s distance by
several methods, the old one by observing transits of Venus, one of which
Cook went out to observe in 1768, and two of which recurred in 1874 and
1882; new ones by observations of Mars or one of the minor planets at a
favorable opposition, and by determining the velocity of light.
The recent discovery of a minor planet, Eros, which in one part of its
orbit is nearer the earth than Mars, has recently revived interest in this
method, and a combined attack is in contemplation.
It has been long known that light has a finite velocity, but we had to
wait till the 60’s before Fizeau and Foucault showed us how to determine its
exact value. The methods introduced by them have been recently applied by
Cornu, Newcomb, and Michelson, and the resulting value is slightly less
than three hundred thousand metres per second. Combining this with the
constant of aberration, the distance of the sun can be determined.
It is wonderful how these vastly different methods agree in the resulting
mean distance. At the beginning of the century it stood roughly at ninety-

five million miles; this has been reduced to ninety-three million nine
hundred and sixty-five thousand miles. The extreme difference between the
old and new values of the solar parallax, two-fifths of a second of arc, is
represented by the apparent breadth of a human hair viewed at a distance of
about one hundred and twenty-five feet.
Knowing the distance of the sun, the way is open to us to determine, by
a method suggested by Galileo, the distances of those stars which occupy a
different position among their fellows, as seen from opposite points in the
earth’s orbit round the sun, points one hundred and eighty-six million miles
apart. We now know the distances of many such stars, Bessel having
determined the first in 1838. The nearest star to us, so far as we know, is
Centauri, the light of which takes four and a half years to reach us. Not
many years ago Pritchard applied photography to this branch of inquiry; we
may, therefore, expect a still more rapid progress in the future.
With regard to masses. We naturally must first know that of the earth;
having its size, if we can determine its density, the rest follows.
The problem of determining the mean density of the earth occupied the
minds of many workers during the nineteenth century. Newton (about 1728)
pointed out how it could be deduced by observing the deviation from the
vertical of a plumb-line suspended near a large mass of matter—a
mountain, the volume and density of which could be previously determined.
This method, which is very laborious and requires the greatest skill and
most delicate instruments, has been employed several times, by Bouguer
and Condamine, in 1738, at Chimborazo; Maskelyne, in 1774, at
Schehallien in Scotland; and James, at Arthur’s Seat, near Edinburgh.
At the beginning of the century another method was introduced by
Cavendish. This consists in measuring the attraction of two large spheres of
known size and mass, such as two balls of lead on two very small and light
spheres, by means of a torsion balance constructed by Mitchell for this
purpose.
The most recent determination by this method, and one which is
considered to give us perhaps the most accurate value, is that which is due
to the skill and ingenuity of Professor Boys. His improvement consisted in
constructing a most delicate torsion balance; the attracted spheres consisted
of small gold balls suspended by a quartz fibre carrying a mirror to indicate

the amount of twist. The whole instrument was quite small, and could easily
be protected from air currents and changes of temperature, while the use of
the quartz fibres reduced to a minimum one of the greatest difficulties of the
Cavendish experiment. The value of the mean density of the earth is now
considered to be 5.6, which means that if we have a globe of water exactly
the same size as our own earth, the real earth would weigh just 5.6 times
this globe of water. The earth’s weight, in tons, does not convey much idea,
but that it is six thousand trillions may interest the curious. This
determination has enabled the masses of the sun, moon, planets and
satellites, and many sidereal systems to be accurately known in relation to
the mass of the earth.

SOME ACHIEVEMENTS OF MATHEMATICAL
ANALYSIS

Uranus, a planet unknown to the ancients, was discovered by its
movement among the stars by William Herschel in 1781. It was not until
1846 that another major planet was added to the solar system, and this
discovery was one of the sensations of the century.
The story of the independent discovery of Neptune by Adams and Le
Verrier, who were both driven to the conclusion that certain apparent
regularities in the motion of Uranus were due to the attraction of another
body travelling on an orbit outside it, has been often told. The subsequent
discovery of the external body not far from the place at which their
mathematical analysis had led them to believe it would be seen, will forever
be regarded as a fine triumph of the human intellect.
But the results of the inquiries which now concern us are generally of
not so sensational a character, although they lie at the root of our knowledge
of celestial motions. They more often take the shape of tables and
discussions relating to the movements of the bodies which make up our
solar system.
Gauss may be said to have led the way during the nineteenth century by
his Theoria molus corporum coelestium solem ambientium. This was a
worthy sequel to the Méchanique Céleste, in which work, towards the end

of the eighteenth century, Laplace had enshrined all that was known on the
planetary results of gravitation.
In later years Le Verrier and Newcomb have been among the chief
workers on whom the mantle of such distinguished predecessors has fallen.
From them the planet and satellite tables now in use have been derived.
But the motion of our own satellite, the moon, has had fascinations for
other analysts besides those we have named.
The problem, indeed, of the moon’s motion is one of the most difficult,
and has taxed the ingenuity of astronomers from an early date. Even at the
present day it is impossible to predict the exact position of the moon at any
one moment owing to inequalities and perturbations, the exact varying
values of which are not known.
The two most important theories of the motion of the moon completed
towards the middle of the century were due to Hansen and Delaunay. The
former’s appeared in 1838, the lunar tables being published later (1857),
while the latter’s was published in 1860.
Hansen’s theory had for its chief object the formation of tables; to
avoid the inconvenience of using in his calculations series which slowly
converge, he inserted numerical values throughout. In Hansen’s solution the
problem is one actually presented by nature, allowance being made for
every known cause of disturbance. There is one disadvantage, namely, that
should observations demand a change in any of the constants used, there is
no means of making any correction in the results.
Delaunay’s theory surmounted this difficulty, but at the expense of still
greater inconvenience for making an ephemeris. The slow convergence of
certain series involved an immense amount of labor to give sufficiently
approximate results.
More recently, as the century was closing, Dr. Brown took up the
subject and made a fresh attempt to calculate the motion of our satellite. It
may be stated that he adopts all Delaunay’s modifications of the problem
and works them out algebraically; but there are many technical differences
which it would be out of place to mention here.
Enough has been stated to show that there is not likely to be any breach
of continuity in the treatment of this most important problem.

Another attack on the moon, and, incidentally, its motion, has recently
been made by another analyst, Professor George Darwin; grappling with all
the consequences of tidal friction, he has been able to present to us the past
and future history of our satellite. Beginning as a part of the material
congeries from which subsequently some fifty million years ago both earth
and moon, as separate bodies, were formed, it has ever since been extending
its orbit, and so retreating farther away from its centre of motion, while the
period of the earth’s rotation has been increasing at the same time, from a
possible period of some three hours when the moon was born, to one of one
thousand four hundred hours when the day and month will be equal,
something like one hundred and fifty million years being required for the
process.

STELLAR EVOLUTION

It was only in the 80’s, after thousands of observations of the spectra of
stars, nebulæ, and comets had been secured, that the full meaning of the
revelations of the spectroscope began to dawn upon the world.
Before the introduction of spectrum analysis all stars were supposed to
be suns, and the only difference recognized among them was one of
brilliancy and the variation of brilliancy in the case of some of them.
It ultimately came out that great classes might be recognized by the
differences of their spectra, which were ultimately traced to differences in
their chemistry and in their temperature, as determined by the extension of
the spectra in the ultra-violet, the whiter stars being hotter than the red ones,
as a white-hot poker is hotter than a red-hot poker.
Next there was evidence to show that a large proportion of the stars
were not stars at all like the sun, but swarms of meteorites; and in this way
the mysterious new stars which appear from time to time in the heavens,
and a large number of variable stars, were explained as arising from
collisions among such swarms.
The inquiry which dealt with the spectroscopic results, having thus
introduced the ideas of meteor swarms and collisions to explain many
stellar phenomena, went further and showed that the various chemical

changes observed in passing from star to star might also be explained by
supposing the whole stellar constitution to arise from cool meteoritic
swarms represented by nebulæ, the changes up to a certain point being
explained by a rise of temperature due to condensation towards a centre.
Here the new view was opposed to that of Laplace, advanced during the last
century, that the stars were produced by condensation and cooling; but
Kelvin had shown, before the new view was enunciated, that Laplace’s
view was contrary to thermodynamics, a branch of science which had
developed since Laplace published his famous Exposition du Système du
Monde.
After all the meteorites in the parent swarm had been condensed into
the central gaseous mass, that mass had to cool. So that we had in the
heavens not only stars more or less meteoritic in structure, of rising
temperature, but stars chiefly gaseous, of falling temperature. It was
obvious that representatives of both these classes of stars might have nearly
the same mean effective temperature, and therefore more or less the same
spectrum. A minute inquiry entirely justified these conclusions.
So far had the detailed chemistry of the stars been carried in the latter
years of the century that the question of stellar evolution gave rise to that of
inorganic evolution generally, the sequence in the phenomena of which can
only be studied in the stars, for laboratory work without stint has shown that
in them we have celestial furnaces, the heat of which transcends that of our
most powerful electric sparks. In this way astronomy is paying the debt she
owes to chemistry.

THE SUN AND HIS SYSTEM

Although the outer confines of space have, as we have seen, been
compelled to bring their tribute of new knowledge by means of the
penetrating power possessed by modern telescopes, and the cameras and
spectroscopes attached to them, the study of the near has by no means been
neglected, and for the reason that in astronomy especially we must content
ourselves in the case of the more distant bodies by surmising what happens
in them from the facts gathered in the region where alone detailed
observations are possible.

Thus what we can learn about the sun helps to explain what we discern
much more dimly in the case of stars; a study of the moon’s face we are
compelled to take as showing us the possibilities relating to the surface
condition of other satellites so far removed from us that they only appear as
points of light.
To begin, then, with the sun. Where a volume might be written, a few
words must suffice. I have already stated that at the beginning of the
nineteenth century the prevailing opinion was that it was a habitable globe.
It was limited to the fiery ball we see. At the end of the century it is a body
of the fiercest heat, and the ball we see is only a central portion of a huge
and terribly interesting mechanism, the outer portions of which heave and
throb every eleven years. Spots, prominences, corona, everything feels this
throbbing.
Although the discovery of spots on the sun was among Galileo’s first
achievements, it was reserved for the last half of the nineteenth century to
demonstrate their almost perfect periodicity.
Thanks to the labors of Schwabe, Wolf, Carrington, and De la Rue,
Stewart, and Loewy, we now know that every eleven years the spots wax
and wane; Tacchini and Ricco, during the last thirty years, have proved that
the prominences follow suit, and the fact that the corona also obeys the
same law was established during the American eclipse of 1878.
The study of solar physics consists in watching and recording the
thermal, chemical, and other changes which accompany this period. Some
of these effects can be best studied during those times when the ball itself is
covered by the moon in an eclipse. Then the outer portions of the sun are
revealed in all their beauty and majesty, and all the world goes to see.
But it is the quiet daily work in the laboratory which has enabled us to
study the sun’s place in relation to the other stars, and so to found a
chemical classification of all the stars that shine.
From the sun we may pass to his system, and first consider the nearest
body to us—the moon.
While some astronomers have been discussing the movements and
evolution of our satellite, others have been engaged upon maps of its
surface, upon questions dealing with a lunar atmosphere, or a study of the

origin of the present conformations and of possible changes. The science of
selenology may be said to have been founded by Schröter at the beginning
of the century, but it required the application of photography in later years
to put it on a firm basis. Maps of the moon have been prepared by
Lohrmann, Beer and Mädler, and Schmidt, the latter showing the positions
of more than thirty thousand craters.
Very erroneous notions are held by some as to what we may hope to do
in the examination of the moon’s surface by a powerful telescope. A power
of a thousand enables us to see it as if we were looking at York from
London. It is recorded that Lassell once said that with his largest reflector in
a “fit” of the finest definition he thought he might be able to detect whether
a carpet as large as Lincoln’s Inn Fields was round or square. Under these
circumstances, then, we may well understand that the question of changes
on the surface has been raised from time to time never to be absolutely
settled one way or the other. By many the existence of an atmosphere is
denied, and this is a condition which would negative changes, anything like
the geological changes brought about on the surface of the earth, but the
idea is now held by many that there is still an atmosphere, though of great
tenuity.
The last few years of the century were rendered memorable from the
lunar point of view by the publication and minute study of a most admirable
series of photographs of the moon obtained by the great equatorial Coudé of
the Paris Observatory by Loewy and Puiseaux. One of the chief points
aimed at has been to determine the sequence of the various events
represented by the rills, craters, and walled plains, the mountain ranges and
seas. This work is still in progress, the fourth part of the atlas being
published in 1900; but enough has already appeared to indicate that the
results of the inquiry when completed will be of the most important kind.
The authors have already come to the conclusion that the lunar and
terrestrial sea-bottoms much resemble each other, inasmuch as both have
convex surfaces. The lunar seas began by sinking of vast regions; the
formidable volcanic eruptions of which the moon has been the scene have
taken place in times equivalent to those labelled “recent” in geological
parlance. There is evidence that the axis of the moon has undergone great
displacements, and four great periods of change have been made out.

Finally they state that there is serious ground to believe that there is an
atmosphere of some sort remaining.
It may readily be understood that with each increase of optical power
new satellites of the various planets have been discovered. Soon after the
discovery of Neptune a satellite was noted by Lassell. In 1846 both he and
the eagle-eyed observer Dawes independently discovered another satellite
(Hyperion) of Saturn. Lassell was rewarded in the next year by the
discovery of two more satellites of Uranus; but, strangest observation of all,
in 1877 Hall discovered at Washington two satellites of Mars some six or
seven miles only in diameter, one of them revolving round the planet in
seven and one-half hours at a distance of less than four thousand miles. As
the day on Mars is not far different in duration from our own, this tiny
satellite must rise in the west and south three times a day!
Wonderful as this discovery was, it is certainly not less wonderful when
we consider it in connection with a passage in Gulliver’s Travels, so true is
it that truth is stranger than fiction. Swift, in his satirical reference to the
inhabitants of Laputa, writes: “They have likewise discovered two lesser
stars, or satellites, which revolve round Mars, whereof the innermost is
distant from the centre of the primary planet exactly three of his diameters
and the outermost five; the former revolves in the space of ten hours; and
the latter in twenty-one and a half.”
The last discovery of this kind has been that of an inner satellite of
Jupiter by Barnard in 1892.
The planets from Mercury to Saturn were known to the ancients. I have
already referred to the discovery of Uranus by Herschel’s giant telescope,
not long before the nineteenth century was born, and of Neptune, by
analysis, towards the end of the first half of the century. With regard to what
modern observations have done in regard to their physical appearance, the
first place in general interest must be given to Saturn and Mars.
Saturn has always been regarded as the most interesting of the
planetary family on account of its unique rings. Many subdivisions of the
rings, and a dusky ring, first seen by Dawes and Bond, have been
discovered during the last sixty years.

The meteoritic nature of the rings was suggested by Clerk Maxwell in
1857, and Keeler’s demonstration of the truth of this view by means of the
spectroscope, a few years ago, was brilliant in conception and execution.
But during the last half of the century the interest centred in Mars has
been gradually increasing. The drawings made during the opposition of
1862, when compared with those made by Beer and Mädler (1830–40),
made it perfectly clear that in this planet we had to deal with one strangely
like our own in many respects. There were obviously land and water
surfaces; the snow at the poles melted in the summer-time; clouds were
seen forming from time to time, and the changing tones of the water
surfaces suggested fine and rough weather.
Afterwards came the revelation of the hawk-eyed Schiaparelli,
beginning in the year 1877, and his wonderful map of the planet’s surface.
The land surfaces, instead of being unbroken, were cut up, as an English
farm is cut up by hedges; straight lines of different breadths and tints
crossed the land surfaces in all directions, and at times some of them
appeared double. Schiaparelli naturally concluded that they were rivers—
water channels—and being an Italian he used the appropriate word canali.
This, unfortunately, as it turned out, was translated canals. Now canals are
dug, ergo there were diggers. From this the demonstration, not of the
habitability, but of the actual habitation, of Mars was a small step, and the
best way of signalling to newly found kinsmen across some thirty millions
of miles of space was discussed.
The world of science owes a debt of gratitude to Mr. Percival Lowell
for having taken out to the pure air and low latitude of Arizona an eighteen-
inch telescope for the sole purpose of accumulating facts tending to throw
light upon this newly raised question. This he did in 1894. Schiaparelli has
continued his magnificent observations through each opposition when the
planet is most favorably situated for observation, and since 1896 Signor
Cerulli, armed with a fifteen-inch Cooke, in the fine climate of Italy, has
joined in the inquiry, so that facts are now being rapidly accumulated. It has
been stated that markings similar to the strange so-called “canals” on Mars
are to be seen on Mercury, Venus, and even on the satellites of Jupiter. Mr.
Percival Lowell does not hesitate to proclaim himself in favor of their being
due, in Mars, to an intelligent system of irrigation. Signor Cerulli claims
that wherever seen they are mere optical effects. We may be well content to

leave to the twentieth century a general agreement on this interesting
subject.
Finally, in our survey of our own system, come comets and meteor
swarms. One of the most fruitful discoveries of the century, that comets are
meteor swarms, we owe to the genius of Schiaparelli, A. H. Newton, and
other workers on those tiny celestial messengers which give rise to the
phenomena of “falling” or “shooting” stars.
The magnificent displays of 1799, 1833, 1866, and, alas! that which
failed to come in 1899, we now know must be associated with Tempel’s
Comet. This is by no means the only case so far established; the connection
will in the future be closer still when the orbits of the various swarms
observed throughout the year shall be better known.
Comets which attract public attention by their brightness and grandeur
of form are rather rare, and, in fact, only twenty-five of such have been seen
since 1800. We have, however, with the great advance in instrumental
equipment, been able to discover many which are scarcely visible to the
naked eye, and this has swollen the number of comets very considerably. In
the seventeenth century we find that only thirty-two were observed, while
in the eighteenth this number was more than doubled (seventy-two). In the
nineteenth century more than three hundred were placed on record, which is
practically more than four times the number seen in the eighteenth.
The last great comet visible any considerable time was that discovered
by Donati in 1858, and so carefully observed by Bond. It is unfortunate that
since the importance, in so many directions, of spectroscopic observations
of comets has been recognized they have been conspicuous by their
absence.

THE CONNECTION BETWEEN SOLAR AND
TERRESTRIAL WEATHER

Everybody agrees that all the energy utilized on this planet of ours,
with the single exception of that supplied by the tides, comes from the sun.
We are all familiar with the changes due to the earth’s daily rotation
bringing us now on the side of our planet illuminated by the sun, then

plunging us into darkness; that changes of season must necessarily follow
from the earth’s yearly journey round the sun is universally recognized.
On the other hand, it is a modern idea that those solar phenomena
which prove to us considerable changes of temperature in the sun itself,
may, and indeed should, be echoed by changes on our planet, giving us
thereby an eleven-year period to be considered, as well as a year and a day.
This response of the earth to solar changes was first observed in the
continuous records of those instruments which register for us the earth’s
magnetism at any one place. The magnetic effects were strongest when
there were more spots, taking them as indicators of solar changes. Lamont
first (without knowing it) made this out, at the beginning of the latter half of
the century (1851), from the Göttingen observations of the daily range of
the declination needle. Sabine the next year not only announced the same
cycle in the violence of the “magnetic storms” observed at Toronto, but at
once attributed them to solar influence, the two cycles running concurrently.
It is now universally recognized that terrestrial magnetic effects, including
auroræ, minutely echo the solar changes.
The eleven-year period is not one to be neglected.
Next comes the inquiry in relation to meteorology. Sir William
Herschel, in the first year of the century, when there were practically neither
sun-spot nor rainfall observations available, did not hesitate to attack the
question whether the price of wheat was affected by the many-or-few-spot
solar condition. He found the price to be high when the sun was spotless,
and vice versa.
By 1872, however, we had both rainfall and sun-spot observations, and
the cycle of the latter had been made out. Meldrum, the most distinguished
meteorologist living at the time, and others, pronounced that the rainfall
was greatest at sun-spot maximum, and, further, that the greatest number of
cyclones occurred in the East and West Indies at such times.
This result with regard to rainfall was not generally accepted, but
Chambers showed shortly afterwards an undoubted connection between the
cycles of solar spots and barometric pressure in the Indian area.
By means of a study of the widened lines observed in sun spots an
attempt has been recently made to study the temperature, history of the sun

since about 1877, and the years of mean temperature and when the heat was
in excess (+) and defect (-) made out, have been as follows:

Heat
condition mean + mean − mean + mean − mean
1886– 1891–
Years 1869 1876 1881
87 92
1870– 1877– 1882– 1881–
1892
75 80 86 91

Having these solar data, the next thing to do was to study the Indian
rainfall during the southwest monsoon for the years 1877–1886, the object
being to endeavor to ascertain if the + and − temperature pulses in the sun
were echoed by + and − pulses of rainfall. The Indian rainfall was taken
first because in the tropics the phenomena are known to be the simplest. It
was found that in many parts of India the + and − conditions of solar
temperature were accompanied by + and − pulses, producing pressure
changes and heavy rains in the Indian Ocean and the surrounding land.
These occurred generally in the first year following the mean condition, that
is, in 1877–78 and 1882–83.
The rainfalls at Mauritius, Cape Town, and Batavia were next collated
to see if the pulses felt in India were traceable in other regions surrounding
the Indian Ocean to the south and east. This was found to be the case.
A wider inquiry was followed, we are told, with equal success, so that
we are justified in hoping that the question of the dependence of terrestrial
upon solar weather has made a step in advance.
But just as the general public and practical men took little heed of the
connection between sun spots and magnetism until experience taught them
that telegraphic messages often could not “get through” when there were
many sun spots, so the same public will not consider the connection in
regard to meteorology unless the forecasting of droughts and famines be
possible.
The recent work suggests that, if the recent advances in solar physics
be considered, the inquiries regarding rainfall may be placed on a firmer

basis than they could possibly have had in 1872, and that such forecastings
may become possible.
What was looked for in 1872 was a change in the quantity of rain at
maximum sun spots only, the idea being that there might be an effective
change of solar temperature, either in excess or defect, at such times and
that there would be a gradual and continuous variation from maximum to
maximum.
We see that the rainfalls referred to above justify the conclusions
derived from the recent work that two effects ought to be expected in a sun-
spot cycle instead of one. There was excess of rainfall, not only near the
sun-spot maximum, but near the minimum.
If the authors of this communication to which I refer are right, then
droughts and famines occur in India because the rain pulses, which are
associated with the solar-heat pulses, are of short duration. When they cease
the quantity of rain which falls in the Indian area is not sufficient, without
water storage, for the purposes of agriculture; they are followed, therefore,
by droughts, and at times subsequently by famines. They divide the period
1877—89 as under:

{ 1877.
Rain from − pulse { 1878.
{ 1879 (part).
{ 1879 (part).
No rain pulse { 1880 (central year).
{ 1881 (part).
{ 1881 (part).
{ 1882.
Rain from + pulse
{ 1883.
{ 1884 (part).
{ 1884 (part).
{ 1885 }
No rain pulse (central year).
{ 1886 }
{ 1887 (part).

{ 1887 (part).
Rain from − pulse { 1888.
{ 1889.
Their statement is based on the fact that all the famines which have
devastated India for the last seventy years have occurred at intervals of
eleven years, or thereabouts, working backward and forward from the
central years 1880 and 1885–86 in the above table, the middle years, that is,
between the pulses.
Mr. Willcocks, in a paper read at the Meteorological Congress at
Chicago, remarked that “famines in India are generally years of low flood
in Egypt.”
It is now pointed out that the highest Niles follow the years of the + and
− pulses, as does the highest rainfall in the Indian area.
Even if these results, which were communicated to the Royal Society
of London five weeks before the end of the century, be confirmed, it may be
pointed out that Sir William Herschel’s suggestion of 1801 will have
required a whole century for its fulfilment, so slowly do those branches of
science move which have not already led to some practical development.

Norman Lockyer.

PHILOSOPHY

I t theis acontinuous
natural illusion that makes us think of each century as exhibiting
development of one tendency of mind through a series
of stages whose differences are only of secondary importance, and, on the
other hand, to regard the steps from one century to another as corresponding
to some marked transition of thought, as if the world had been suddenly
precipitated into a new sphere of existence. For some purposes a rough
generalization of this kind, that breaks at stated intervals the continuity of
time, may, perhaps, be convenient. When, however, we begin to look at
things more closely, we discover that it is impossible thus to cut through the
historical connection of events, as it were, “with a hatchet.” We discover,
for example, that the characteristics of the eighteenth century were strongly
marked only in one period of it; and that what we call the spirit of the
nineteenth century was born some time before the year 1800, and has never
quite prevailed over other tendencies. At the same time, there is an
important difference indicated by these two loosely used names, and as it is
always easier to define things by contrast, it may help us to make our
subject more definite to consider what they mean.

I

It is too late now to “abuse the eighteenth century,” which had its good
and evil, like other periods. It is commonly conceived as the era of
individualism and analysis, the era of logical enlightenment and sceptical
criticism; and, again, as the era of liberation from groundless superstitions
and fictitious claims of authority; the era in which mankind seemed for the
first time to throw off the weight of the past and to enter without fear upon

the enjoyment of their earthly heritage. The science of Newton had given
the last blow to the astronomy that made the earth the centre of the
universe. It had undermined and discredited the simple theology that
explained the whole material world as a cosmos arranged for the supply of
human needs. At the same time, the progress of biology was bringing man
to a consciousness that as a physical being he is only primus inter pares in
the animal kingdom, and the decay of religious belief was making him
realize his finitude, the limits of his natural existence, as, perhaps, he had
never done before, at least never since the beginning of the Christian era.
Earth seemed to be disconnected from heaven, and the human race thrown
upon its own resources. By the new enlightenment all powers, ecclesiastical
or political, were stripped of the mysterious sanctity that had once invested
them. “The nimbus was taken away from the heads of the gods and rulers of
the world.” Every authority that claimed man’s homage was weighed in the
scales of the understanding, and, so weighed, every such authority was
found wanting. The State had come to be regarded as only a collection of
individuals who had agreed to live together under a ruler deriving all his
claims from their consent, and invested with no divine right to their
allegiance. The Church was no longer a sacred institution governed by
priests who held their commission directly from God, but only a sort of
spiritual police agency, an ally of the State in the restraint of vice and crime,
or, at best, in Protestant countries, a society for mutual improvement. Men
were “free and equal,” each standing face to face with his fellows,
admitting no superiority or superstition of hero-worship in regard to any
one of them. And the Deity, if his existence were not denied, tended to
become a mere “Supreme Being,” who was removed to such a distance
from mankind that he could hardly be reached by their reverence, still less
by their love.
At the same time, the influences which, in one point of view, seemed to
limit and narrow human existence, in another point of view tended to
liberate and enlarge it. If they excluded the idea of the infinite from man’s
life, they emancipated him from many degrading superstitions, which in an
earlier age had held him “all his lifetime subject to bondage.” And as the
pressure from above was lightened the individual seemed to become master
of himself and of his destiny. If the king could no longer say, “L’Etat c’est
moi,” the rights of the subject were vindicated; if the authority of the
Church was weakened, the bonds of free inquiry were broken; if

imagination ceased to fill men with the awe and wonder of higher powers,
the way was opened up for scientific and industrial development; if God
was regarded as unknowable, “the proper study of mankind was man,” and
that study could now be pursued without fear or hinderance. Poetry and
religion might be impoverished, the sense of the binding force of social
relations might be weakened, but interest in the bettering of man’s earthly
condition was awakened, and with it came a new desire for justice to all, a
new intolerance of human suffering, and a new demand that the lot of the
class “which is most numerous and poor” should be made less wretched and
insecure, and, towards the end of the century, a new turn was given to its
leading thought, for an effort was made to discover in the nature of the
individual himself the equivalent of those universal powers which the
enlightenment had banished from the external world and from the life of
society. Rousseau carried individualism to an extreme point, at which it
became its own correction, and taught men to find within their own souls
the infinite which they could no longer discover without. Rejecting in the
first instance all social conventions as unjust limitations of the natural man,
and adopting the prevailing theory of the time, that the State is only the
product of a contract between independent persons, he yet discovered in the
individual thus liberated from all external pressure a “common reason,” and
“a general will,” which could reorganize his life and bind him to his fellow-
men and to God. This great idea, which appears in Rousseau rather as a
stroke of insight, an intuition of genius—lifting him above his first thoughts
and insensibly changing their meaning—was grasped by Kant as the
principle of a new philosophy and worked out in a comprehensive system
that dealt with all the great problems of thought and life. Kant, indeed,
seemed, like Rousseau, to begin on the plane of eighteenth-century
individualism, but, influenced as he was by the philosophy of Leibnitz, he
from the first conceived the individual as in himself universal; or, to speak
more exactly, as having a universal principle realized in him. Thus, though
in one aspect of his being man is a finite object among other objects,
confined within limits of space and time, and forming only a link in the
chain of natural causation, in another aspect of it, as a conscious self, he is
emancipated from all these limitations. For—such is Kant’s argument—a
knowing subject, for whom the whole finite world, including his own finite
existence, is an object of knowledge, cannot himself be comprehended in
that world or limited by any of its conditions. As there can be no world of

objects except for a self, it is impossible that such a self should be merely
one of these objects. Thus, as knowing, or capable of knowing, all things,
man cannot be identified with any of them; or if, from one point of view, as
an individual, he is so identified, yet he has within him a universal principle
that carries him beyond the limits of his individuality. And this contrast
shows itself also in his practical life. For if as an object he appears to be but
an animal organism, moved by the impressions of pleasure and pain which
he receives from other objects, yet in his inner moral life man is revealed to
himself as a self-determining subject, emancipated from all sensuous
motives and from the necessity of nature which they bring with them, and
conscious of subordination only to the law of duty, which is the law of his
own reason. And that law, in spite of every pressure of circumstance from
without, and of every impulse of passion from within, he knows that he
ought to obey, and therefore he knows that he can obey it. Thus, in Kant’s
theory, the two extreme views of humanity, as natural and as spiritual, as
limited to a finite individuality, hemmed in by necessities on every side, and
yet as possessing a universal capacity of knowing, and an absolute power of
self-determination, these two views are presented in sharp antithesis, and at
the same time held together as different aspects of one life. In fact, we have
here, as it were, compressed into a nutshell, the result of the whole history
of eighteenth-century individualism, which began by depressing man and
ended by exalting him; which, with one of its voices, seemed to reduce him
to the level of an animal, a mere part of the partial world, a transitory
phenomenal existence among other phenomena; and then, with its other
voice, proceeded to recognize him as a member of the intelligible world, a
“spectator of all time and existence,” and gifted with the absolute freedom
of a will which could be determined by nothing but itself. “The solitary,”
says Aristotle, “must be either a god or a beast,” and the eighteenth century,
in its conception of the individual, seemed to oscillate between the one and
the other till Kant, awaking to the impossibility of omitting either aspect of
his being, demanded that he should be conceived as both at once. Kant thus
set the problem of the future; and if he did not solve it, he at least showed
the futility of any narrow or one-sided solution and the direction in which
an adequate solution could alone be sought. In short, Kant asked the
question to which the nineteenth century, in all its philosophical reflection,
has been striving to find an answer.

For in philosophy, as in other departments of knowledge, the work of
the nineteenth century has been one of mediation and reconciliation. It has
been an endeavor to break down the sharp antithesis of philosophical and
scientific theories that was characteristic of an earlier time. In the writings
of the greatest thinkers, the oppositions of materialism and spiritualism, of
sensationalism and idealism, of empiricism and a priori speculation, of
individualism and socialism, all the great oppositions of theoretical and
practical philosophy, which formerly were held to be absolute and
irreconcilable, have been modified, restated, reduced to the relative
antagonism of the different aspects of one truth. The great controversies of
the past have thus passed into a new phase, in which absolute statements
pro and con have become, as it were, antiquated; and the question is no
longer whether a particular doctrine or its opposite is true, but what are the
elements of truth and error in each of them, and how we can attain to a
comprehensive view of things, in which justice is done to both. And if it be
asked, what are the principles or ideas that have suggested this reconciling
work, and have been the guides of the greatest scientific or philosophic
writers in attempting to achieve it, I think the answer must be that they are
the idea of organic unity, and, as implied in that, the idea of development.
Goethe and Hegel, in Germany; Comte, in France; Darwin and Spencer, in
England, are writers who almost span the whole range of difference in
modern thought; but they, and a multitude of others in every department of
study, have been inspired by the ideas of organism and development. And
they have all used them somewhat in the same way to turn the edge of the
old controversial weapons, or to lift thought above the “yes” and “no” of
opposing dogmatisms. It is true that the definitions or interpretations of the
ideas of organism and development given by these writers are very
different, and often, indeed, so sharply opposed that they seem to bring
back the old controversies in a new form. But this does not alter the
significance of the general fact; for, in the first place, the use of an idea by
any writer is by no means always limited by his own interpretation of it;
and, in the second place, the true interpretation of the idea is that which
contains the secret of its power and prevalence, and it must in the long run
gain the victory over all other interpretations of it. We may, therefore, fairly
say that these ideas have been the marked ideas of the century, the
conscious or unconscious stimulus of its best thought; and that they have
been working, and are working still, in the direction of a deeper and more

comprehensive irenicon between the different tendencies of the human
mind than has been attained in any previous stage of the history of
philosophy.
Against such a general characterization of an age, there is the same
objection which Burke indicated when he said that “he could not draw up
an indictment against a nation.” We are taking a distant and general view of
a period, in which all its inequalities of movement, all the ebb and flow of
opinion, are lost sight of, and only one main current of thought is visible.
We may get a step nearer to the subject by distinguishing three periods in
the century, in which there is a partial difference of tendency. The first
period, which we may roughly define as lasting well on into the 30’s, is, in
the main, a period of construction, of creative thought, in which the great
germinating ideas that distinguished the century are more or less adequately
expressed in different countries, and in which they receive a first, somewhat
hasty, application to all departments of human knowledge. Idealistic
philosophy, which gave the fullest expression to those ideas, seems for a
time to carry all before it in Germany; and a similar movement of thought,
less definitely reflective or speculative, enriches the literature of other
countries. In the next period, lasting until the 70’s, the new ideas do not lose
their hold upon men’s minds, but there is a certain critical recoil against
them, a tendency to explain them away. The first premature synthesis of
idealistic philosophy is attacked by a scepticism, which seems at times as if
it would measure back the whole way to the individualistic materialism of
an earlier age, or which only avoids that extreme to fall into a scientific
agnosticism, at first sight even more hostile to the claims of philosophy. But
the lesson of Kant could never be altogether forgotten, nor could the
negative or sceptical tendencies of the Critique of Pure Reason be
permanently separated from the positive results of his later writings. And
the great scientific movement of the time, which at first seemed to draw
away all interest from speculative inquiry, tended in the long run, especially
by the advance of biological study, to raise metaphysical questions which
the methods of science were incapable of answering. Hence, in the latest
decades of the century, there has come a revival of interest in philosophy,
and especially in the idealistic philosophy of its first years. But if
philosophy has revived, it is in a more critical and cautious form, and
accompanied by a clear consciousness that the only true idealism is that
which is able to absorb and assimilate all the data supplied by empirical

investigation, and do justice to all the results of the special sciences. The
general movement of thought in the nineteenth century has thus, on the
whole, taken an idealistic direction; but there has come with it also a deeper
consciousness of the immense difficulty of a comprehensive synthesis; of
the inefficacy of any easy monism or optimism, that would pluck the fruit
of knowledge before it is ripe; of the infinite labor and patience, the
sympathetic appreciation of the opposing views of others, and constant and
unsparing criticism of our own, which are needed for the construction of a
true philosophy.

II

In a short article like this, it is impossible to give more than a few
indications of the way in which this three-fold schema of the history of
nineteenth-century philosophy should be filled up. To give any definite
impression, the writer must, so to speak, put on the seven-leagued boots of
Jack the Giant Killer; in other words, however conscious he may be of the
truth that dolus latet in generalibus, he must generalize and be content to
mention only a few leading names in illustration of the tendencies of
thought of which he speaks.
It is the instinct of each new generation to vindicate its freedom by
rebelling against the authority of its predecessors; and when a new idea
begins to influence human thought, it usually, on its first appearance, shows
that side which is most antagonistic to the spirit of the past. Thus the
peculiar nineteenth-century movement begins with a reassertion of the
universal as against the individual, which is so emphatic that it looks like a
return to Spinozism. Schelling is the most prominent philosophical
representative of this tendency. In the works which he wrote about the
beginning of the century, he broke away even from the universalized
individualism of Fichte, and gave emphatic prominence to the great
philosophical commonplace—which had been almost forgotten by the
previous age—that there is an identity which is below or above all
distinction, and that the universe is one through all its multiplicity, and
permanent through all its changes. His maxim—that there are none but
quantitative differences in things, and that all these, even the difference of

mind and matter, disappear in the “indifference” of the Absolute—was like
a declaration of war against the “enlightenment.” It meant that philosophy
was no longer content to regard the whole as the sum of the parts, but could
look upon the distinction of the parts only as a differentiation of the whole.
With Schelling, indeed, this differentiation was in danger of being reduced
to a mere appearance and the unity of the Absolute was on the point of
vanishing in a bare or abstract identity. But his strong assertion of the unity
beneath all difference, of the priority of the universal to all particulars, was
perhaps necessary, ere the true conception of the organic unity of the world
could be arrived at. And the correction soon came with Hegel, who
maintained that the absolute is “not substance, but subject.” For this meant
that the absolute is a self-differentiating principle, realizing itself in a world
of difference which is no mere appearance, but its own essential
manifestation; and again—what is the counterpart or complementary truth
to this—that in the world there are “degrees of reality,” and that “mind is
higher in degree than nature.” But these ideas could hardly have been
understood until the uncompromising assertion of the absolute unity had
been made, and until the subjectivity of the Kantian and Fichtean points of
view had once for all been set aside.
The philosophy of Hegel derives its power from the way in which it
strikes what, as I have already said, was the key-note of the nineteenth-
century philosophy. In the first place, it is a philosophy of reconciliation,
which attempts, through a criticism of the oppositions of philosophical
theory, to reach a point of view in which they are all seen to be
subordinated to the unity of one principle. His attack upon the “law of
contradiction,” as formulated by scholastic logicians, meant simply that
absolute distinctions are unmeaning, and that the only real differences are
differences within a unity. On this principle he tried to show that all the
oppositions of thought and things which have found expression in
philosophy are relative oppositions, which find a solution or reconciliation
in the life and movement of the whole. Hence he maintained that in all the
great controversies that have divided the world, in metaphysics and
psychology, in ethics and theology, the combatants have really been co-
operators. Both sides, to use the expression of Leibnitz, have been “right in
what they affirmed and wrong only in what they denied.” And their conflict
has been the means of the evolution of a fuller truth than that which was
contained in the doctrine of either party. In the second place, Hegel is

guided throughout by the conception of the universe—and, in a sense, of
every even relatively independent existence in it—as an organism, every
element in which implies the whole, every change in which is a phase of its
self-evolution. For his logical doctrine of the “notion” (as Begriff is
commonly translated) means simply that we do not see anything truly until
we comprehend it as a whole, in which one principle manifests itself
through all the difference of the parts and—just through their distinctions
and their relations—binds itself into one individual—reality. In this sense,
everything just so far as it has an independent individual existence at all is
an organism. Lastly, while thus conceiving the universe as organic, Hegel
maintained that it is not a natural but a spiritual organism. For the limited
scope of a natural organism and its process cannot be regarded as
commensurate with a universe, which comprehends all existence, whether
classed as organic or inorganic. Only the conscious and self-conscious unity
of mind can overreach and overcome such extreme antagonisms, and reduce
them all to elements in the realization of its own life. We must, therefore,
think of the universe as an organism which includes nature, but manifests
its ultimate principle only in the life of man. We may add that in all this
Hegel attempted to show that he was only working out in the sphere of
speculative thought what Christianity had already expressed for the
ordinary consciousness, according to its half-pictorial methods of
representation.
While this is the general meaning of Hegelianism, it must be added that
Hegel was more successful in formulating these ideas in their logical or
metaphysical form than in applying them to the results of the special
sciences of nature, which he only knew at second hand; or even to the
different provinces of the spiritual life and history of man, which he had
studied more thoroughly. In both cases his data were very incomplete, and
the scientific interpretation of them had not then been carried far enough to
prepare—as, according to Hegel himself, it should prepare—for the final
interpretation of philosophy. There is another circumstance to be taken into
account, a circumstance which deeply affected Hegel and all the writers of
his time. In the slow process of human history the new wine is always at
first poured into old bottles, and only when the old bottles burst is an effort
made to find new ones that will contain it safely. Hence the development of
the new spirit in philosophy seemed often to go hand-in-hand with a
movement of restoration in politics and religion which was not easily

distinguishable from reaction. Just as the politicians of the time could find
for the newly awakened spirit of nationality no other embodiment than the
institutions of the ancient régime, and tried to revive the old system
destroyed by the Revolution, with only a few repairs and additions, so the
great philosophical writers sought generally to reanimate the old scheme of
life and thought by means of the new ideas, rather than completely to recast
it in accordance with them. Hence, although Hegel’s principle of evolution
was as hostile to reaction as to revolution, as hostile to an authoritative
system that denied the rights of the individual as to mere individualism, his
particular doctrines, both in politics and theology, took a strongly
conservative tinge. When we look more closely we see that it is only as
restoration is at the same time reformation, as it makes the old forms the
expression of a new life, that Hegel could logically defend them. But the
form which he gave to his ideas was perplexing; it tended in many minds to
identify the principle of development, which means that the future can only
spring out of the past and the present, with the defence of the status quo in
Church and State; and, on the other hand, to confuse the forces of progress
with those of revolution. Thus the mediating, reconciling power of the new
doctrine was for a time obscured, and its effect in raising men’s minds
above the old levels of controversy was delayed.

III

In other countries during the earlier decades of the century a similar
movement of thought is discernible, though it was not carried out anywhere
with the same philosophical thoroughness as in Germany. In France the
organic idea did not find any very powerful representative till the time of
Comte, and even in his expression of it there is a certain ambiguity. In his
well-known law of development, indeed, he seems to reproduce the
individualistic doctrine of the eighteenth century, and to deny the reality of
the universal, both in its theological and its philosophical form. But already
in the last volume of his Positive Philosophy, when he begins to deal with
human society, he maintains that “the individual man is an abstraction, and
that there is nothing real but humanity”; and in his Positive Politics he treats
this unity of mankind as not only real, but divine. In that work, moreover,

he makes another step. Rejecting at once the obstructions of the
individualists and those of the socialists, he rises to the conception of a
social organism, which gives play to the competitive energy of individuals,
and yet binds them together in its own more comprehensive life. In
England, before the close of the eighteenth century, the same spirit had
found a representative in Burke, who rejected entirely the idea of a social
contract, and maintained that the State is based on an unconscious reason of
society, which is far wiser than the conscious reason of even the wisest
individuals. In general, however, the spiritualistic movement of the earlier
part of the century took, among the English-speaking people, rather a poetic
and literary than a philosophical form. And the imperfect attempts of
Coleridge to transplant German ideas into England—attempts followed up
with signal energy by Frederic Denison Maurice—hardly constitute an
exception to this rule. In this connection, also, as one who partly grasped
the organic idea of social life and its development, but who gave it a
somewhat imperfect and even contradictory expression, I may mention a
later writer, Thomas Carlyle, whose imaginative genius and moral
enthusiasm did much to breathe a new life into history. Though not a
philosopher in any technical sense, he was, like his friend Emerson, a
vehicle of philosophical ideas, and he contributed greatly to scatter the seed
of idealism upon British soil. His Calvinistic pessimism, indeed, makes a
curious contrast with the fearless optimism of the new country which is
characteristic of Emerson; but whether great men are to be regarded as
“heroes to be worshipped,” according to the teaching of the one, or as
“representative men,” who are to be followed because they express what all
are thinking, according to the ideas of the other, we are led, in both cases, to
a deeper view of the solidarity of human society and of its spiritual basis.

IV

It is difficult to determine more than approximately the beginning of
special movements of thought; for the different nations of the civilized
world are not exactly contemporaneous in their development, and in each
nation there are always individuals who lag behind the time or hasten on
before it. But, speaking generally, we may say that as early as the fourth

decade of the century a certain reaction had set in against the conclusions of
idealistic philosophy, and especially against the organic idea of human life;
and a tendency was even shown to revert, so far as possible, to the methods
and ideas of the eighteenth century. The reasons for this change are various.
In Germany the succession of great philosophers had come to an end, and
their followers were smaller men, who were inclined too much to repeat the
formulas, but had little of the creative power, of their predecessors. More
attention, therefore, began to be paid to the protests of writers like Herbart
and Schopenhauer, who, even in the hour of its triumph, had criticised and
attacked the prevailing philosophy. Again, the physical sciences were
advancing by “leaps and bounds,” and there was a growing inclination to
believe in the universal validity of the mechanical methods of explanation
to which they owed their success, and even in those sociological and
historical studies to which the idealistic philosophy had given so great an
impetus. The progress of empirical research and the increase of the
materials of knowledge caused much of the work of Hegel and his
followers to seem inadequate, if not entirely to set it aside. Even in
Germany, where the new ideas had taken a distinctly philosophical shape,
they seemed to lose their hold in the controversies that attended the
breaking up of the Hegelian school; and in other countries, where they
never found such a systematic expression, they were even less able to resist
the attack now made upon them. Furthermore, as I have already indicated,
writers of an idealistic tendency, in their recoil from the enlightenment, had
devoted themselves so much to an appreciation of institutions derived from
the past that they seemed to have no eyes for the defects of these
institutions, and to confuse evolution with restoration.
The general result of all these influences was, then, to discredit
philosophy and exalt science, so far as might be, into its place. Either the
abstract methods of the physical sciences were proclaimed as adequate for
the discovery of all truth, or, if this was seen to be impossible, agnosticism
was professed in regard to all subjects to which these methods could not be
applied. Even the phenomena of life were supposed to be capable of
explanation by the action and reaction of the parts or elements of the
physical organism, and Huxley looked forward to the time when man with
all his spiritual endowments should be shown to be only the “cunningest of
nature’s clocks.” The new science of psychophysics, which arose in
Germany and has been cultivated with so much zeal by Wundt and others in

all civilized countries, seemed to carry the method of physics into the
investigation of mind, and some of its students were ready to maintain that
it was the only psychology that deserved the name of science. Darwin’s
great work on the Origin of Species, in so far as it set aside the idea of
special creation and referred the “purposiveness” of organic structures to a
process in which the external environment, and not any inward power of
self-adaptation, was the controlling factor, seemed to bring a new
reinforcement to the same way of thinking. And he and his followers were
not slow to apply the theory of natural selection to the life of man, as well
as to that of plants and animals. Finally, the historical studies, which were
now cultivated with an energy to an extent hitherto unexampled, and
immensely extended the knowledge of the process whereby the present has
grown out of the past, were invaded by a similar spirit; and the historical
method was maintained to be a solvent which could disintegrate all
metaphysical conceptions of ethics or politics or even of theology. The
account of the genesis of any idea was regarded as reducing its claims to the
level of the elements or rudiments out of which it had sprung, and thus as
enabling the scientific historian to explain, or explain away, the spiritual by
the natural in all human life and experience. All things appeared again to be
pointing towards a system of thought which would resolve ethics and
psychology into physiology, and physiology into chemistry and physics.
At the same time the victory of this tendency was always more
apparent than real. In the first place, “out of the eater came forth meat”—
that very advance of the special sciences, which in its earlier stages had
tended to throw all speculative thought into the shade, in the long run
caused the need of philosophy to be again felt. In particular, the study of
development in the organic world, which had received so great a stimulus
from the work of Darwin, could not be carried on without the aid of higher
conceptions than were required for the guidance of the physicist. The
hypothesis of natural selection might expel the idea of design in the cruder
form of a special creation of every distinct species; and the emphasis which
it had laid upon the outward conditions of growth might seem unfavorable
to the higher conception of an immanent teleology of the organism, but it
was confessed by its author to be an incomplete theory of development, and
Darwin himself, when he turned his attention to the evolution of man, found
it necessary to supplement it by what might be called the converse theory of
sexual selection; thus adding a principle of co-operation to his first principle

of competition. And Mr. Spencer, who defined growth as a process of
integration and differentiation, little as he might himself intend it, was
really putting into popular language the Hegelian idea of evolution—an
idea which necessarily involved the conception of a self-determined end.
Evolutionists might cling, as they still cling, to the belief that, though
constantly and necessarily speaking of purpose, they could eliminate it from
the result of their investigations by the hypothesis of Darwin, or,
subsequently, of Weissmann; but their discussions, especially when they
were extended to the historical development of man, could not but
reawaken the great controversy whether in the ultimate explanation of
things it is more reasonable to “level up,” or to “level down,” to explain the
higher by the lower, or the lower by the higher. That both explanations are
necessary, nay, that no teleology can be of much worth which does not
presuppose a thorough inquiry into the causal connections of particular
phenomena, was admitted by all modern idealists. But they began to press
the question whether the unity of the whole is not prior to its distribution
into parts, and does not govern their relations with each other; and, in
particular, whether it is possible in the case of organic beings, and
especially of organic beings possessed of consciousness and self-
consciousness, to be satisfied with a mode of explanation that treats them as
mere collections of material elements which act and react externally upon
each other. Whatever its value as a provisional hypothesis, can such a mode
of explanation be finally regarded as adequate for the explanation of the
nature of the world as a whole, or, indeed, of any one existence in it, that
has even a relative independence or separate being of its own?
But, in the second place, a revival of the idealistic philosophy was
made necessary by an obvious weakness which clung to the scientific
materialism of the nineteenth century from the very beginning. The Kantian
criticism of knowledge, which could not be entirely neglected, had
convincingly proved that in our experience objects can be known only in
relation to a subject, and matter only in relation to mind. But, if so, how
could the latter be explained by the former? Even to those who had not fully
understood this doctrine, it became evident that mind is at least co-ordinate
with matter, and cannot be treated as a mere “epiphenomenon” of it. Mr.
Spencer, therefore, had to take refuge in the strange notion that we are
possessed of “two consciousnesses”: the consciousness of ideas within us,
and the consciousness of motions without us; and that neither of these can

be resolved into the other, though both are the phenomena of an
unknowable Absolute. It is in this citadel of ignorance that Huxley tries to
intrench himself; but the place was taken before it could be occupied. The
self-contradiction of an unknowable Absolute, and the equal though less
obvious self-contradiction of a dualistic separation between two aspects of
our life—which, as a matter of fact, are never, and logically can never be,
divided—could not long be maintained against a criticism armed with the
weapons of Kant and his idealistic successors. Already, in the 50’s, the cry
“Back to Kant” was raised in Germany, and, not long after, it led in England
and America to a renewed study of the German idealistic writers, in which
Dr. Hutchison Sterling and the late Professor Green took a leading part. It
was soon obvious to every one who had learned the lesson of critical
philosophy that the agnostic dualism of Mr. Spencer was due to a
fundamental misconception of what is meant by the subjectivity of
knowledge. It was pointed out that if we have the consciousness of object
and subject only in relation to each other, it is not necessary to seek for the
principle of their unity in any Tertium Quid which is neither the one nor the
other. That which Mr. Spencer sought in an unknowable Absolute was “in
our mouths and in our hearts”; it was to be found in the inseparable unity of
experience, in which the inward and the outward are correlative elements.
Agnosticism was a sort of spiritual refuge for the destitute constructed by
those who had renounced their heritage: who, in other words, had by their
abstractions separated the elements of experience from each other, and were
thus forced to seek beyond experience for the unity which they had lost.
The true remedy for the evil was to give up such abstract ways of thinking
and to learn to “think things together”; in other words, to recognize the
organic relation of the inner and the outer life, and to explain the parts by
the whole, and not the whole by the artificially severed parts.

V

The great distinguishing feature of the last two decades of the century
has been a movement of approximation, partly conscious and partly
unconscious, between the representatives of science, and particularly of
those sciences that deal with special aspects or elements of human life, on

the one hand, and the representatives of idealistic philosophy on the other.
The reconciling ideas of an earlier time have become better understood and
have shown more effectively their power to reconcile. Not that this
mediating power had previously been entirely unfelt. Even in the time when
philosophy was most discredited in Germany, Lotze, in whom a cautious
critical temper was combined with deep moral and religious sympathies,
and a practical knowledge of the biological and medical sciences with
careful studies of Kant and Hegel, sought to show how an idealistic view of
the universe and of human life could be maintained consistently with the
fullest recognition of scientific methods and results. And though his system
was, on the whole, rather a compromise than a true reconciliation of
philosophy and science, yet it has undoubtedly had very great influence in
modifying the ideas of the opposing schools of thought and narrowing the
ground of controversy between them. Thus the old English empirical
psychology, which was represented by the Mills and by Mr. Bain, has
gradually widened its scope in the hands of writers like Professor Ward and
Mr. Stout, at first probably through the study of Herbart and then by contact
with the revived idealistic movement. On the other hand, we may notice
how idealistic writers, like Mr. Bradley and Mr. Bosanquet, have tried to
absorb every lesson that can be learned from empiricism, and to shun with
the utmost care the very suspicion of anything like dogmatism. Mr.
Bradley’s denunciations of a “too easy monism” and a philosophy that turns
the living world into a “ballet of bloodless categories” are too well known
to be more than referred to. Nor is this the place to discuss whether his fear
of such a result has not sometimes led him into compromises which are
inconsistent with his own fundamental principle that the world must be
conceived as an intelligible system. In any case, we may fairly point to his
work and to the work of other writers animated by a similar spirit, as
showing the growing prevalence of that reconciling spirit which seeks at
once to do justice to all the results of empirical inquiry and of the
investigations of the special sciences, and yet at the same time to give them
a new interpretation in the light of an idealistic philosophy. It is impossible
within our limits to illustrate this view of the tendencies of the time by
further reference to the recent philosophical literature of England and
America, or of Germany and France. Still less can I refer to the numerous
books on special departments of inquiry in ethics and theology, in sociology
and in history, in which the “ideally organic view of life and the world,” as

we may call it, has shown its mediating and reconciling influence. Nor can I
do more than refer to the counter current of pessimism, which has found its
most distinguished representatives in Hartmann and Nietzsche; the former a
man of great wealth of thought and dialectical power, whose philosophy is
idealistic in all but its ultimate principle, and is indeed pessimistic only by
an exaggeration of the opposition between the conscious and the
unconscious working of reason; the latter, hardly a philosopher at all but
rather a writer of pungent and suggestive aphorisms, winged with indignant
passion against prevalent opinions—aphorisms which always contradict
some one, and often contradict each other. From Nietzsche at his best we
may receive a useful warning against too easily satisfying ourselves with
the commonplaces of idealistic optimism; from Hartmann we may derive
very considerable help in estimating the difficulties that have to be met by
those who would seek to work out idealistic principles into a systematic
view of the world. But, without attempting to enter upon any more detailed
criticism of these or other important writers of recent years, I shall devote
the space that remains to one general thought as to the present state of
controversy, in relation to the fundamental principles of philosophy.

VI

Ever since the revival of the study of Kant, the main conflict in
philosophy has ceased to lie between materialism and idealism. It has rather
become a conflict between those who take up some position analogous to
that of Kant and those who seek to carry out the idealistic principle to all its
consequences. For the essential characteristic of Kant’s position lay in his
sharp division between the spheres of knowledge and of faith—between a
knowledge which was confined to phenomena and their connection in
experience, and a faith of practical reason, which reached beyond
experience to apprehend that which is noumenally real. Even the
agnosticism of Mr. Spencer might be regarded as a modification of the
Kantian point of view, in so far as his denial of the possibility of knowing
the absolute is based on Mansel’s version of the Kantian antinomies; while
his description of the “vague consciousness” of the absolute which he bids
us worship may be regarded as representing that faith which, in Kant’s

view, enables us to pierce the veil of the phenomena and grasp the ultimate
reality of things. And in the latter part of the century there has been a
continual germination of similar theories, theories agreeing with the
Kantian philosophy at least in making some kind of dualistic division
between the sphere of clearly defined knowledge and the sphere of ideal or
spiritual faith, and also in confining the former to phenomena while the
latter is held to be capable of rising in some way from the phenomenal to
the real. One of the earliest fruits of the Neo-Kantian movement in
Germany was Lange’s History of Materialism, which insisted on the
strictest interpretation of the lesson of the Critique of Pure Reason, that
scientific knowledge is confined to the empirical and phenomenal, but
which maintained also the chartered freedom of imagination to feed our
hopes with the idea of a world not realized, or realizable, under the
conditions of finite experience. And, with a different aim, but in a similar
spirit, Ritschl, borrowing some of his weapons from Lotze, sought to take
away from philosophy the right to investigate the spiritual truths of religion,
and maintained that such truths were given in a kind of intuition of faith
which is above criticism and which some of his followers identify, like
Kant, with the demands or postulates of the moral consciousness. Other
writers, following Schopenhauer, have sought to emancipate the will from
the intelligence and to give it an independent power of estimating values.
The great effort to bring science and philosophy together—which, as we
have seen, has characterized the later years of the century—has itself
naturally given rise to many such dualistic compromises, of which Lotze’s
philosophy was among the earliest. And it is partly to Lotze’s influence that
we owe the tendency, visible in some of the most important recent
contributions to philosophy, to regard our actual experience as having an
intuitive completeness which is beyond all analysis, while reflective
thought on the other hand is conceived as having a purely analytic and
discursive operation, which can grasp only the severed fragments of the
given reality and connect them externally to each other, but which can never
restore the organic whole again. Here, too, we seem by another way to be
landed in the same conclusion, viz., that we are perpetually poised between
an ideal which we cannot verify, but which yet is held to be our only vision
of reality, and a definite result of knowledge, which only gives us what is
abstract and phenomenal. Yet it is difficult to understand how such an
organic idea of the universe can exist except for the thinking intelligence,

and how the thought that grasps it can be separated from the discursive
thought by which the different elements of reality are brought into relation.
How, indeed, can there be any thought which is not both discursive and
intuitive at once, any thought which connects the parts without resting upon
the unity of the whole to which they belong?
All these different compromises are really different forms of the
Kantian dualism, but they supply convenient cities of refuge for those who
are unwilling to admit that faith is but implicit reason, and that it is always
possible to translate its intuitions of truth into explicit logic. There is much
excuse, indeed, in many cases for such unwillingness when we consider
how often reason has presented itself as purely a critical or dissolving
power, and how often abstract theories which grasp only one aspect of
things have been set forth as complete explanations of religion or morality
or some other of the higher interests of life. It has always to be kept in view
that it is in something like immediate perception that truth is given in the
first instance, and that philosophy, therefore, must always be in a sense
toiling after the intuitions of faith. Yet, on the other hand, to hold that there
is anywhere an abstract division between the two is to hold that faith is
essentially irrational; it is to exalt it above reason in a way that inevitably
leads in the end to its being depressed below reason. If, however, this view
can be maintained it must lead in the long run to the rejection of all dualistic
compromises. And there are already many who hold that after the unstable
equilibrium of the Kantian theory has been shaken there is no secure
standing-ground for philosophy short of a thorough-going idealism. Yet
even they have learned by experience how dangerous it is to snatch
prematurely at the readiest idealistic interpretation of facts; and they are
aware how easy it is to fall into a simple optimistic theory, which slurs over
difficulties instead of solving them. They know that if Hegel or any one
ever pretended, or could reasonably be interpreted as pretending, to
construe the universe a priori, the pretence was futile, and that a true and
valuable idealism can be reached only through the interpretation of the data
of experience by the special sciences, and the reinterpretation of the results
of these sciences by philosophy. They hold, in short, that if the well-known
saying of Hegel is to be taken for truth, both of its clauses must be equally
emphasized, and that no philosophy can safely maintain that “what is
rational is actual” which has not gone through all the effort that is necessary
to prove that “what is actual is rational.”

Edward Caird.

MEDICINE

INTRODUCTION

F or countless generations the prophets and kings of humanity have
desired to see the things which men have seen, and to hear the things
which men have heard in the course of the wonderful nineteenth century. To
the call of the watchers on the towers of progress there had been the one sad
answer—the people sit in darkness and in the shadow of death. Politically,
socially, and morally the race had improved, but for the unit, for the
individual, there was little hope. Cold philosophy shed a glimmer of light
on his path, religion in its various guises illumined his sad heart, but neither
availed to lift the curse of suffering from the sin-begotten son of Adam. In
the fulness of time, long expected, long delayed, at last Science emptied
upon him from the horn of Amalthea blessings which cannot be
enumerated, blessings which have made the century forever memorable;
and which have followed each other with a rapidity so bewildering that we
know not what next to expect. To us in the medical profession, who deal
with this unit, and measure progress by the law of the greatest happiness to
the greatest number, to us whose work is with the sick and suffering, the
great boon of this wonderful century, with which no other can be compared,
is the fact that the leaves of the tree of Science have been for the healing of
the nations. Measure as we may the progress of the world—materially, in
the advantages of steam, electricity, and other mechanical appliances;
sociologically, in the great improvement in the conditions of life;
intellectually, in the diffusion of education; morally, in a possibly higher
standard of ethics—there is no one measure which can compare with the
decrease of physical suffering in man, woman, and child when stricken by

disease or accident. This is the one fact of supreme personal import to every
one of us. This is the Promethean gift of the century to man.

THE GROWTH OF SCIENTIFIC MEDICINE

The century opened auspiciously, and those who were awake saw signs
of the dawn. The spirit of Science was brooding on the waters. In England
the influence of John Hunter stimulated the younger men to the study of the
problems of anatomy and pathology. On the Continent the great Boorhaave
—the Batavian Hippocrates—had taught correct ways in the study of the
clinical aspects of disease, and the work of Haller had given a great impetus
to physiology. The researches of Morgagni had, as Virchow had remarked,
introduced anatomical thinking into medicine. But theories still controlled
practice. Under the teaching of Cullen, the old idea that humors were the
seat of disease had given place to a neuro-pathology which recognized the
paramount influence of the nervous system in disease. His colleague at
Edinburgh, Brown, brought forward the attractive theory that all diseases
could be divided into two groups, the one caused by excess of excitement—
the sthenic—the other by a deficiency—the asthenic—each having its
appropriate treatment, the one by depletion, the other by stimulation. In a
certain measure Hahnemann’s theory of homœopathy was a reaction against
the prevalent theories of the day, and has survived through the century,
though in a much modified form. Some of his views were as follows:
“The only vocation of the physician is to heal; theoretical knowledge is
of no use. In a case of sickness he should only know what is curable and the
remedies. Of the diseases he cannot know anything except the symptoms.
There are internal changes, but it is impossible to learn what they are;
symptoms alone are accessible; with their removal by remedies the disease
is removed. Their effects can be studied in the healthy only. They act on the
sick by causing a disease similar to that which is to be combated, and which
dissolves itself into this similar affection. The full doses required to cause
symptoms in the well are too large to be employed as remedies for the sick.
The healing power of a drug grows in an inverse proportion to its substance.
He says, literally: ‘Only potencies are homœopathic medicines.’ ‘I
recognize nobody as my follower but him who gives medicine in so small

doses as to preclude the perception of anything medicinal in them by means
either of the senses or of chemistry.’ ‘The pellets may be held near the
young infant when asleep.’ ‘Gliding the hand over the patient will cure him,
provided the manipulation is done with firm intention to render as much
good with it as possible, for its power is in the benevolent will of the
manipulator.’ Such is the homœopathy of Hahnemann, which is no longer
recognized in what they call homœopathy to-day.”—(A. Jacobi.)
The awakening came in France. In 1801 Bichat, a young man,
published a work on general anatomy, in which he placed the seat of
disease, not in the organs, but in the tissues or fabrics of which they were
composed, which gave an extraordinary impetus to the investigation of
pathological changes. Meanwhile, the study of the appearances of organs
and bodies when diseased (morbid anatomy), which had been prosecuted
with vigor by Morgagni in the eighteenth century, had been carried on
actively in Great Britain and on the Continent, and the work of Broussais
stimulated a more accurate investigation of local disorders. The discovery
by Laennec of the art of auscultation, by which, through changes in the
normal sounds within the chest, various diseases of the heart and lungs
could be recognized, gave an immense impetus to clinical research. The art
of percussion, discovered by Avenbrugger in the eighteenth century, and
reintroduced by Corvisart, contributed not a little to the same. Laennec’s
contributions to the study of diseases of the lungs, of the heart, and of the
abdominal organs really laid the foundation of modern clinical medicine. A
little later Bright published his researches on diseases of the kidneys, from
which we date our knowledge of this important subject. One of the most
complicated problems of the first half of the century related to the
differentiation of the fevers. The eruptive fevers, measles, scarlet fever, and
small-pox, were easily recognized, and the great group of malarial fevers
was well known; but there remained the large class of continued fevers,
which had been a source of worry and dispute for many generations. Louis
clearly differentiated typhoid fever, and by the work of his American pupils,
W. W. Gerhard and Alfred Stillé, of Philadelphia, and George B. Shattuck,
of Boston, typhus and typhoid fevers were defined as separate and
independent affections. Relapsing fever, yellow fever, dengue, etc., were
also distinguished. The work of Graves and Stokes, of Dublin, of Jenner
and Budd, in England, of Drake, Dickson, and Flint, in America,
supplemented the labors of the French physicians, and by the year 1860 the

profession had reached a sure and safe position on the question of the
clinical aspects of fevers.
The most distinguishing feature of the scientific medicine of the
century has been the phenomenal results which have followed experimental
investigations. While this method of research is not new, since it was
introduced by Galen, perfected by Harvey, and carried on by Hunter, it was
not until well into the middle of the century that, by the growth of research
laboratories, the method exercised a deep influence on progress. The lines
of experimental research have sought to determine the functions of the
organs in health, the conditions under which perversion of these functions
occur in diseases, and the possibility of exercising protective and curative
influences on the processes of disease.
The researches of the physiological laboratories have enlarged in every
direction our knowledge of the great functions of life—digestion,
assimilation, circulation, respiration, and excretion. Perhaps in no
department have the results been more surprising than in the growth of our
knowledge of the functions of the brain and nerves. Not only has
experimental science given us clear and accurate data upon the localization
of certain functions of the brain and of the paths of sensatory and of motor
impulses, but it has opened an entirely new field in the diagnosis and
treatment of the diseases of these organs, in certain directions of a most
practical nature, enabling us to resort to measures of relief undreamed of
even thirty years ago.
The study of physiology and pathology within the past half-century has
done more to emancipate medicine from routine and the thraldom of
authority than all the work of all the physicians from the days of
Hippocrates to Jenner, and we are as yet but on the threshold.

THE GROWTH OF SPECIALISM

The restriction of the energies of trained students to narrow fields in
science, while not without its faults, has been the most important single
factor in the remarkable expansion of our knowledge. Against the
disadvantages in a loss of breadth and harmony there is the compensatory

benefit of a greater accuracy in the application of knowledge in specialism,
as is well illustrated in the cultivation of special branches of practice.
Diseases of the skin, of the eye, of the ear, of the throat, of the teeth,
diseases of women and of children, are now studied and practised by men
who devote all their time to one limited field of work. While not without
minor evils, this custom has yielded some of the great triumphs of the
profession. Dentistry, ophthalmology, and gynæcology are branches which
have been brought to a state of comparative perfection, and very largely by
the labors of American physicians. In the last-named branch the blessings
which have been brought to suffering women are incalculable, not only as
regards the minor ailments of life, but in the graver and more critical
accidents to which the sex is liable.
One of the most remarkable and beneficial reforms of the century has
been in the attitude of the profession and the public to the subject of
insanity, and the gradual formation of a body of men in the profession who
labor to find out the cause and means of relief of this most distressing of all
human maladies. The reform movement inaugurated by Tuke in England,
by Rush in the United States, by Pinel and Esquirol in France, and by
Jacobi and Hasse in Germany, has spread to all civilized countries, and has
led not only to an amelioration and improvement in the care of the insane,
but to a scientific study of the subject which has already been productive of
much good. In this country, while the treatment of the insane is careful and
humanitarian, the unfortunate affiliation of insanity with politics is still in
many States a serious hinderance to progress.
It may be interesting to take a glance at the state of medicine in this
country at the opening of the nineteenth century. There were only three
schools of medicine, the most important of which were the University of
Pennsylvania and the Harvard. There were only two general hospitals. The
medical education was chiefly in the hands of the practitioners, who took
students as apprentices for a certain number of years. The well-to-do
students and those wishing a better class of education went to Edinburgh or
London. There were only two or three medical journals, and very few books
had been published in the country, and the profession was dependent
entirely upon translations from the French and upon English works. The
only medical libraries were in connection with the Pennsylvania Hospital
and the New York Hospital. The leading practitioners in the early years

were Rush and Physick, in Philadelphia; Hossack and Mitchill, in New
York; and James Jackson and John Collins Warren, in Boston. There were
throughout the country, in smaller places, men of great capabilities and
energy, such as Nathan Smith, the founder of the Medical Schools of
Dartmouth and of Yale, and Daniel Drake in Cincinnati. After 1830 a
remarkable change took place in the profession, owing to the leaven of
French science brought back from Paris by American students. Between
1840 and 1870 there was a great increase in the number of medical schools,
but the general standard of education was low—lower, indeed, than had
ever before been reached in the medical profession. The private schools
multiplied rapidly, diplomas were given on short two-year sessions, and
nothing contributed more to the degeneration of the profession than this
competition and rivalry between ill-equipped medical schools. The
reformation, which started at Harvard shortly after 1870, spread over the
entire country, and the rapid evolution of the medical school has been one
of the most striking phenomena in the history of medicine in the century.
University authorities began to appreciate the fact that medicine was a great
department of knowledge, to be cultivated as a science and promoted as an
art. Wealthy men felt that in no better way could they contribute to the
progress of the race than by the establishment of laboratories for the study
of disease and hospitals for the care of the sick poor. The benefactions of
Johns Hopkins, of Sims, of Vanderbilt, of Pierpont Morgan, of Strathcona,
of Mount-Stephen, of Payne, and of Levi C. Lane and others have placed
scientific medicine on a firm basis.

THE GROWTH OF PREVENTIVE MEDICINE

Sanitary science, hygiene, or preventive medicine may claim to be one
of the brightest spots in the history of the nineteenth century. Public hygiene
was cultivated among the Egyptians, and in the Mosaic law it reached a
remarkable organization. The personal hygiene of the Greeks was embraced
in the saying, “The fair mind in the fair body,” and the value of exercise and
training was fully recognized. The Romans, too, in public and private
hygiene, were our superiors in the matter of water supply and baths. But
modern sanitary science has a much wider scope and is concerned with the

causes of disease quite as much as with the conditions under which these
diseases prevail. The foundations of the science were laid in the last century
with Jenner’s discovery of vaccination. Howard, too, had grasped the
association of fever with overcrowding in the jails, while the possibility of
the prevention of scurvy had been shown by Captain Cook and by Sir
Gilbert Blaine.
Preventive medicine was a blundering, incomplete science until
bacteriology opened unheard-of possibilities for the prevention of disease.
Before discussing some of the victories of preventive medicine it will be
well to take a brief survey of the growth of the following subject:

SCIENCE OF BACTERIOLOGY

From the brilliant overthrow by Pasteur, in 1861, and by Koch and
Cohn, in 1876, of the theory of spontaneous generation, we may date its
modern growth. Wrapped up in this theory of spontaneous generation, upon
which speculation raged centuries before the invention of the microscope,
lies the history of bacteriology.
The ancient Greek and Roman philosophers wrestled with the question,
and very interesting views of the relation of germ life to disease are
preserved to us in their manuscripts. With the invention of the microscope
we can mark the first positive step towards the goal of to-day. A Jesuit
priest, Kircher, in 1671, was the first to investigate putrefying meat, milk,
and cheese with the crude microscope of his day, and left us indefinite
remarks concerning “very minute living worms” found therein. Four years
after Kircher a Dutch linen merchant, Antonius von Leeuwenhoek, by
improving the lenses of the microscope, saw in rain-water, putrefying
fluids, intestinal contents, and saliva, minute, moving, living particles,
which he called “animalculæ.” In medical circles of his day these
observations aroused the keenest interest, and the theory that these
“animalculæ” might be the cause of all disease was eagerly discussed.
Pleincz, of Vienna, after much observation of various fluids, putrefying and
otherwise, wrote in 1762 that it was his firm belief that the phenomena of
diseases and the decomposition of animal fluids were wholly caused by
these minute living things.

Notwithstanding such assertions, from his day on until Pasteur, Koch,
and Cohn finally proved its misconceptions in 1876, the theory of
spontaneous generation held the upper hand in all discussions upon the
question.
The stimulus to research as to the causes of disease along the line of
bacterial origin did not entirely cease to be felt, and the names of Pollender
and Davaine are linked together in the first undoubted discovery of micro-
organisms in disease, when the cause of anthrax, a disease of cattle, was
solved in 1863. Following closely upon Davaine’s researches, the primary
causes of wound infection were worked out, and to the efforts of the British
surgeon Lister are due the great advances of modern surgery.
In rapid succession the presence of bacteria was clearly demonstrated
in relapsing fever, leprosy, and typhoid fever; but far eclipsing all former
discoveries, on account of the magnitude of the difficulties encountered and
overcome, were the brilliant demonstrations of the cause of consumption
and allied diseases, and that of Asiatic cholera, by Dr. Robert Koch in 1882
and in 1884 respectively.
From that time onward innumerable workers have satisfied the critical
scientific world as to the causes of pneumonia, diphtheria, tetanus,
influenza, and bubonic plague, besides many diseases of cattle, horses,
sheep, and other animals and insects.
Having glanced hastily at the history of bacteriology, we may next
consider some facts concerning the germs themselves. What are they? To
the lay mind the words germ, microbe, bacterium, and bacillus often convey
confused ideas of invisible, wriggling, worm-like creatures, enemies of
mankind, ever on the watch to gain a stealthy entrance into our bodies,
where they wreak harm and death. Scientifically considered, however, they
are the smallest of living things yet known. They are not animals, but are
members of the vegetable kingdom, and are possessed of definite yet
varying shapes. They consist of a jelly-like substance called protoplasm,
which is covered in and held in place by a well-formed membrane of a
relatively hard and dense character, exactly similar in composition to the
woody fibre of trees.
According to their shape the bacteria are divided into three chief
groups, called respectively cocci, bacilli, and spirilla. The cocci are

spherical bodies and may exist singly or in pairs, in fours, in clusters, or in
chains. In this group we find the smallest bacteria known, many of them not
over 1-150,000 of an inch in diameter. The bacilli are rod-like bodies,
varying much in size in different species and in members of the same
species. They are larger than the cocci, measuring in length from 1-25,000
of an inch to 1-4000, and in breadth from 1-125,000 to 1-16,000 of an inch.
Many varieties are possessed of organs of locomotion called flagella.
The spirilla resemble the bacilli, except that they are twisted into
corkscrew shapes, or have gently undulating outlines. Upon an average they
are much longer than the bacilli, one species being very long, measuring
about 1-600 of an inch. As seen in the natural state bacteria are found to be
colorless, but it is by the application of various aniline dyes that they are
usually studied. These minute plants increase by a simple method of
division into two equal parts, or by a more complex process of forming a
seed—the so-called spore—which later on develops into the adult form.
Under favorable conditions they are able to multiply at an enormous rate;
for instance, it has been calculated that a bacillus dividing once every hour
would at the end of twenty-four hours have increased to seventeen millions;
and if the division continued at the same rate we should find at the end of
the third day an incalculable number of billions, whose weight would be
nearly seven thousand five hundred tons!
But, fortunately for our welfare, nature by various means renders the
possibility of such a happening entirely beyond the slightest chance of
realization, her greatest barrier being the lack of an adequate food supply.
The distribution in nature of bacteria is wellnigh universal, occurring as
they do in the air we breathe, the water and milk we drink, upon the
exposed surfaces of man and animals, and in their intestinal tracts, and in
the soil to a depth of about nine feet. But it has been noted that at very high
altitudes and in glacier ice none exist, while in the Arctic regions and at sea
far from land their numbers are very few.
The conditions governing their growth involve many complex
problems, but a few of the chief factors concerned are moisture, air, food,
temperature, and light. All bacteria must have moisture, else they die sooner
or later, depending upon the hardness of the species, and none can multiply
without it. A supply of air is by no means essential to all germs. To some it

is absolutely necessary, and such germs are called aerobes. To others air is
wholly detrimental, and they constitute the anaerobes, while to the majority
of bacteria air supply is a matter of indifference, and in consequence they
are grouped under the term facultative anaerobes.
The food supply of many consists of dead animal and vegetable
materials, a few require living tissues, while a small number can exist
wholly upon mineral salts, or even the nitrogen of the air. The lowest
temperature at which some bacteria can multiply is the freezing-point of
water, and the highest 170 degrees Fahrenheit. However, the average range
of temperature suitable to the majority lies between 60 and 104 degrees
Fahrenheit, 98 2-5 degrees Fahrenheit being the most suitable for the
growth of disease-producing germs. Light, ordinarily diffused daylight, or
its absence, is a matter of no moment to most germs, whereas direct
sunlight is a destroyer of all bacteria.
The study of the life histories of these diminutive plants excites the
wonder of those who make observations upon them. It is truly marvellous to
know that these bacteria can accomplish in their short lives of possibly a
few hours or days feats which would baffle the cleverest of chemists if
given years of a lifetime to work upon. They give to the farmer the good
quality of his crops, to the dairyman superior butter and cheese; they assist
in large measure in freeing our rivers and lakes from harmful pollutions.
Here it should be strongly emphasized that those bacteria which cause
disease are only of a few species, all others contributing to our welfare in
countless ways.
Quite as astonishing is the discovery that within the root-knobs of
pease and beans live bacteria which by splitting up mineral salts containing
nitrogen, and by absorbing nitrogen from the air, give it over to the plant so
that it is enabled to grow luxuriantly, whereas, without their presence, the
tiller of the soil might fertilize the ground in vain. It is quite possible that
not alone pease and beans, but all grasses and plants and trees depend upon
the presence of such germs for their very existence, which in turn supply
man and animals with their means of existence. Hence we see that these
nitrifying bacteria, as they are called, if swept out of existence, would be
the cause of cessation of all life upon the globe. And arguing backward, one
prominent authority states it as his belief that the first of all life on this earth

were those lowly forms of plants which only required the nitrogen of air or
salts to enable them to multiply.
Limiting observation now to the sphere of medicine, it will be readily
perceived that the presence of bacterial life in a causative relation to disease
is an object of paramount regard. The following paragraphs will briefly treat
of the diseases associated with micro-organisms and the common modes of
infection in each, the chain of events subsequent to an infection, and the
possibilities of protection or cure by means of substances elaborated in the
body of an individual or animal recently recovered from an infectious
disease:
Anthrax.—A disease chiefly of cattle and sheep, occasionally of man, is
caused by the Bacillus anthracis, discovered in 1849–50 by Pollender and
Davaine. It enters the body through abrasions of the skin, by inhalation of
the spores, or seeds, into the lungs, or by swallowing infected material.
Leprosy.—This disease is caused by a bacillus known as Bacillus
leprae, which was discovered by Hansen in 1879. It is doubtful if it has
been grown outside the body. It is supposed to enter by abrasions of the
skin, but it is very feebly contagious, notwithstanding popular ideas as to its
supposedly highly contagious nature.
Tuberculosis.—All forms of this disease, among which is ordinary
consumption, are caused by a bacillus closely resembling that of leprosy. It
was discovered by Koch in 1880–82, and named Bacillus tuberculosis. The
ways of infection are by inhaling the dried sputum of consumptives,
drinking infected cow’s milk, or eating infected meat.
Typhoid Fever.—A disease of human beings only. Eberth in 1880
discovered the germ causing it and called it Bacillus typhosus. It gains
entrance to our bodies chiefly in the milk and water we drink, which comes
from infected sources; a rarer method is by inhalation of infected air.
Diphtheria.—A disease of human beings chiefly. It is caused by a
bacillus which was described in 1883–84 by Klebs and Loeffler, and is
known as Bacillus diphtheriae, or Klebs-Loeffler bacillus. Its mode of entry
is by inhaling infected air, or by drinking or eating infected milk or food.
Cholera.—This disease is peculiar to human beings. Its native home is
on the banks of the river Ganges in India, where Koch in 1884 was able to

isolate its causative spirillum. Man is infected by drinking contaminated
water or by contact.
Lockjaw, or Tetanus.—Afflicts man, horses, and dogs. The Bacillus
tetani is the most deadly of all known bacteria. It enters the body by
wounds. It was discovered in 1884 by Nicolaier.
Influenza, or the Grip.—Caused by one of the smallest-known bacilli;
discovered in 1892 by Canon and Pfeiffer. Infection spreads by the
scattering about by air-currents of the dried nasal and bronchial secretion of
those suffering from the disease, and its portal of entry is by the nose and
bronchial tubes.
Pneumonia.—Caused by a coccus which grows in pairs and small
chains. It enters the body by means of the respiratory tract. It is present in
the saliva of twenty per cent. of healthy persons. Proved by Frankel in 1886
to be the cause of this disease.
Bubonic Plague.—In 1894 Kitasato and Yersin isolated a small bacillus
in a large number of cases and proved it to be the cause. It enters the body
by means of wounds of the skin, and through bites of fleas from infected
rats, which are said to be one of the chief factors in spreading this dread
malady.
Yellow Fever.—The cause of this disease is still under discussion.
Such are a few of the infectious diseases which we can readily attribute
to the presence of definite micro-organisms in respective cases. But strange
as it may seem, the most typical of all infectious diseases, small-pox, scarlet
fever, measles, and hydrophobia, have as yet not yielded up their secrets.
This is possibly due to the minute size of the micro-organisms concerned,
which make it beyond the power of the best microscope to demonstrate
them. In this connection it has recently been shown by Roux and Nocard
that in the case of the disease known as pleuro-pneumonia of cattle the
causative agent is so very small as just to be barely visible. Again, it is quite
possible that these diseases may be caused by living things we know
nothing about, which may be quite dissimilar from the bacteria.

INFECTION—ITS PROCESSES AND RESULTS

In the foregoing list of diseases associated with specific bacteria,
attention has been drawn to the common modes of infection, or, as they are
technically called, “portals of entry,” and it now remains to touch upon the
main factors, processes, and results following upon the entry into the body
of such disease-producing microbes.
It is a well-known fact that the normal blood has of itself to a
considerable extent the power of killing germs which may wander into it
through various channels. Likewise the tissue cells of the body in general
show similar action depending upon the different cell groups, state of
health, general robustness, and period of life. The germ-killing power varies
in different individuals, though each may be quite healthy. Considered as a
whole, this power possessed by the body against germs is known as
“general resistance.” And when by any means this power of resistance is
lost or diminished, we run grave risks of incurring disease.
Granted a case of infection, let us now trace up briefly what occurs.
Between the period when the bacteria gain a lodgment and that in which the
disease assumes a noticeable form, the patient simply feels out of sorts. It is
during this stage that the blood and tissues are deeply engaged in the
attempt to repel the attacks of the invading microbes.
With varying speed the germs multiply throughout the body generally,
or may be at first localized, or even, as in lockjaw, remain localized
throughout the entire disease. Multiplying in the tissues, they generate in
increasing amounts their noxious poisons, which soon cause profound
changes throughout the body; the patient becomes decidedly ill, and shows
now the signs of an unmistakable infection.
Does the body now give up the fight entirely? No; on the contrary, the
white blood-cells, the wandering cells, and the cells of the tissues most
affected still carry on an unequal fight. From the lymphatic glands and
spleen, armies of white cells rush to the fray and attempt to eat up and
destroy the foe, but possibly in vain; the disease runs its course, to end
either in death or recovery.
How, then, in cases of recovery, are the microbes finally overcome?
This question involves many complex processes which at present are
by no means thoroughly understood, but we will concern ourselves with the

simple principles.
It has been previously mentioned that once the bacteria get a good
foothold the body is subjected to the action of generated poisons, which are
known as toxins. They give rise to such symptoms as loss of appetite,
headache, fever, pains and aches, and even a state of stupor or
unconsciousness. In addition to the active warfare of the white blood-cells,
groups of cells throughout the body, after recovering from the first rude
shock of the toxins, begin to tolerate their presence, then effect a change in
the chemical constitution of the toxins, and finally elaborate substances
which antagonize the toxins and destroy their action altogether, thus lending
aid to the warrior cells, which at last overcome the invading microbes.
Recovery is brought about, and a more or less permanent degree of
immunity against the special form of disease ensues.
Now if we could use these antagonizing substances, or, as they are
called, antitoxins, upon other men or animals sick with a similar disease,
would their bodies be at once strengthened to resist and finally overcome
the disease? Yes, in a certain majority of cases they would, and this is
exactly what scientific observers have noted, worked out, and have
successfully applied. A new art in the healing of disease, which is spoken of
broadly as serum-therapy, or medication by curative or protective serums,
has thus been discovered.
The first observers in this new field were Pasteur and Raynaud in
France in 1877–78, and Salmon and Smith in this country in 1886.
Raynaud, by injecting serum from a calf which had had an attack of cow-
pox, prevented the appearance of the disease in a calf freshly inoculated
with the virulent material of the disease. Pasteur, by using feebly infective
germs of fowl cholera, conferred immunity upon healthy fowls against the
disease, and was able to cure those which were ill. Salmon and Smith
injected small and repeated amounts of the elaborated toxins or poisons of
the bacillus of hog cholera into healthy swine, and were able to confer
immunity upon them.
However, it was not until Behring in 1892 announced his discovery of
an antitoxin serum for diphtheria, along with an undisputed proof of its
value in treatment, that the attention of the scientific world was finally

aroused and stimulated to the appreciation of the great possibilities of
serum-therapy.
Strange as it may seem, much opposition arose to this new method of
treatment, not alone from the lay portions of the community, but even from
the ranks of the medical profession itself. This opposition was due in part to
misconceptions of the principles involved in the new doctrine, and in part to
the falsely philanthropic prejudices of the pseudo-scientific sections of both
parties. But by the persevering work of the enthusiastic believers in serum-
therapy, positive conviction has now replaced misconception and prejudice
in the minds of the majority of its former opponents.
The accumulation of statistical evidence, even where all allowance is
made for doubtful methods of compilation, shows that the aggregate
mortality of diphtheria has been reduced fully fifty per cent. since the
introduction of antitoxic treatment by Behring in 1892.
Since the method of preparation of the commercial diphtheria antitoxin
illustrates the general principles involved in the search for the production of
curative or protective serums for infectious diseases in general, a summary
of the steps in its manufacture will now be given.
A race of diphtheria bacilli, which has been found to yield a poison of
great virulence in alkaline beef broth, is grown for a week or ten days in
this medium. The toxin is then separated and its virulence exactly
determined. It is preserved in sterile receptacles for immediate or future use.
The next step is the inoculation of a suitable animal with the toxin. Of all
animals the horse has been found to meet nearly every requirement. Such an
animal, in a state of perfect health, receives an injection of twenty cubic
centimetres of toxin, along with ten or fifteen of standard antitoxin, beneath
the skin of the neck or fore-quarters, upon three separate occasions at
intervals of five days. After this it receives increasing doses of toxin, alone,
at intervals of six to eight days, until, at the end of two months, it is able to
stand with little discomfort doses of such strength that if given in the first
stage these doses would have quickly caused death.
At this period the horse is bled to a small extent, and its serum tested to
ascertain if prospects are good for the production by the animal of a high
grade of antitoxin. If satisfactory progress has been made, the injections are

continued for another month, when, as a rule, the maximal degree of
antitoxic power in the serum will have been attained.
The horse is now bled to the proper extent, the blood being received in
a sterile jar and placed in an ice-box. Here it coagulates, and the serum
separates from it. When the separation of clot and serum is complete, the
latter is drawn off, taken to the laboratory, and standardized. This being
finished, an antiseptic fluid is added to preserve the serum from
decomposition. It is then bottled, labelled, and sent out for use.
In similar fashion tetanus antitoxin is prepared; and quite recently
Calmette has produced an antitoxic serum for use in snake bite, by injecting
horses with minute increasing doses of snake venom. His experiments have
given some remarkable results, not only in laboratory work, but also in
cases of actual snake bite occurring in man. Thus bacteriological scientists,
after years of laborious work, in the face of much criticism and severe
denunciation, may confidently announce that they have in their possession a
magic key to one of nature’s secret doors. The lock has been turned. The
door stands partly open, and we are permitted a glimpse of the future
possibilities to be attained in the great fight against disease.

PREVENTIVE MEDICINE

The following are some of the diseases which have been remarkably
controlled through preventive medicine:
Small-pox.—While not a scourge of the first rank, like the plague or
cholera, at the outset of the century variola was one of the most prevalent
and dreaded of all diseases. Few reached adult life without an attack. To-
day, though outbreaks still occur, it is a disease thoroughly controlled by
vaccination. The protective power of the inoculated cow-pox is not a fixed
and constant quantity. The protection may be for life, or it may last only for
a year or two. The all-important fact is this: That efficiently vaccinated
persons may be exposed with impunity, and among large bodies of men
(e.g., the German army), in which revaccination is practised, small-pox is
unknown. Of one hundred vaccinated persons exposed to small-pox,
possibly one might take the disease in a mild form; of one hundred

unvaccinated persons so exposed, one alone might escape—from twenty-
five to thirty would die. To be efficient, vaccination must be carried out
systematically, and if all the inhabitants of this country were revaccinated at
intervals small-pox would disappear (as it has from the German army), and
the necessity for vaccination would cease. The difficulty arises from the
constant presence of an unvaccinated remnant, by which the disease is kept
alive. The Montreal experience in 1885 is an object-lesson never to be
forgotten.
For eight or ten years vaccination had been neglected, particularly
among the French-Canadians. On February 28, 1885, a Pullman car
conductor, who came from Chicago, where the disease had been slightly
prevalent, was admitted into the Hôtel Dieu. Isolation was not carried out,
and on the 1st of April a servant in the hospital died of small-pox.
Following her death the authorities of the hospital sent to their homes all
patients who presented no symptoms of the disease. Like fire in dry grass
the contagion spread, and within nine months there died of small-pox three
thousand one hundred and sixty-four persons. It ruined the trade of the city
for the winter, and cost millions of dollars. There are no reasonable
objections to vaccination, which is a simple process, by which a mild and
harmless disease is introduced. The use of the animal vaccine does away
with the possibility of introduction of other disorders, such as syphilis.
Typhus Fever.—Until the middle of the present century this disease
prevailed widely in most of the large cities, particularly in Europe, and also
in jails, ships, hospitals, and camps. It was more widely spread than typhoid
fever and much more fatal. Murchison remarks of it that a complete history
of its ravages would be the history of Europe during the past three centuries
and a half. Not one of the acute infections seems to have been more
dependent upon filth and unsanitary conditions. With the gradual
introduction of drainage and a good water supply, and the relief of
overcrowding, the disease has almost entirely disappeared, and is rarely
mentioned now in the bills of mortality, except in a few of the larger and
more unsanitary cities. The following figures illustrate what has been done
in England within sixty years: In 1838 in England twelve hundred and
twenty-eight persons died of fever (typhus and typhoid) per million of
living. Twenty years later the figures were reduced to nine hundred and
eighteen; in 1878 to three hundred and six of typhoid and to thirty-six of

typhus fever. In 1892 only one hundred and thirty-seven died of typhoid
fever and only three of typhus per million living!
Typhoid Fever.—While preventive medicine can claim a great victory
in this disease also, it is less brilliant, since the conditions which favor its
prevalence are not those specially relating to overcrowding as much as to
imperfect water supply and the contamination of certain essential foods, as
milk. It has been repeatedly demonstrated that, with a pure water supply
and perfect drainage, typhoid fever almost disappears from a city. In
Vienna, after the introduction of good water, the rate of mortality from
typhoid fever fell from twelve per ten thousand of the inhabitants to about
one. In Munich the fall was still more remarkable; from above twenty-nine
per ten thousand inhabitants in 1857 it fell to about one per ten thousand in
1887. That typhoid fever in this country is still a very prevalent disease
depends mainly upon two facts: First, not only is the typhoid bacillus very
resistant, but it may remain for a long time in the body of a person after
recovery from typhoid fever, and such persons, in apparent good health,
may be a source of contamination. With many of the conditions favoring the
persistence and growth of the bacillus outside the body we are not yet
familiar. The experience in the Spanish-American War illustrates how
dangerous is the concentration together of large numbers of individuals.
But, second, the essential factor in the widespread prevalence of typhoid
fever in the United States, particularly in country districts, is the absence of
anything like efficient rural sanitation. Many counties have yet to learn the
alphabet of sanitation. The chief danger results from the impure water
supplies of the smaller towns, the local house epidemics due to infected
wells, and the milk outbreaks due to the infection of dairy farms.
The importance of scrupulously guarding the sources of supply was
never better illustrated than in the well-known and oft-quoted epidemic in
Plymouth, Pennsylvania. The town, with a population of eight thousand,
was in part supplied with drinking-water from a reservoir fed by a
mountain-stream. During January, February, and March, in a cottage by the
side of and at a distance of from sixty to eighty feet from this stream, a man
was ill with typhoid fever. The attendants were in the habit at night of
throwing out the evacuations on the ground towards the stream. During
these months the ground was frozen and covered with snow. In the latter
part of March and early in April there was considerable rainfall and a thaw,

in which a large part of the three months’ accumulation of discharges was
washed into the brook not sixty feet distant. At the very time of this thaw
the patient had numerous and copious discharges. About the 10th of April
cases of typhoid fever broke out in the town, appearing for a time at the rate
of fifty a day. In all about twelve hundred were attacked. An immense
majority of the cases were in the part of the town which received water
from the infected reservoir.
The use of boiled water and of ice made from distilled water, the
systematic inspection of dairies, the scrupulous supervision of the sources
from which the water is obtained, an efficient system of sewage removal,
and, above all, the most scrupulous care on the part of physicians and of
nurses in the disinfection of the discharges of typhoid fever patients—these
are the factors necessary to reduce to a minimum the incidence of typhoid
fever.
Cholera.—One of the great scourges of the present century made
inroads into Europe and America from India, its native home. We have,
however, found out the germ, found out the conditions under which it lives,
and it is not likely that it will ever again gain a foothold in this country or
Great Britain. Since the last epidemic, 1873, the disease, though brought to
this country on several occasions, has always been held in check at the port
of entry. It is communicated almost entirely through infected water, and the
virulence of an epidemic in any city is in direct proportion to the
imperfection of the water supply. This was shown in a remarkable way in
the Hamburg epidemic of 1892. In Altona, which had a filtration plant,
there were only five hundred and sixteen cases, many of them refugees
from Hamburg. Hamburg, where the unfiltered water of the Elbe was used,
had some eighteen thousand cases, with nearly eight thousand deaths.
Yellow Fever.—The cause of this disease is still under discussion. It has
an interest to us in this country from its continued prevalence in Cuba, and
from the fact that at intervals it makes inroads into the Southern States,
causing serious commercial loss. The history of the disease in the other
West India islands, particularly Jamaica, indicates the steps which must be
taken for its prevention. Formerly yellow fever was as fatal a scourge in
them as it is to-day in Cuba. By an efficient system of sanitation it has been
abolished. The same can be done (and will be done) in Cuba within a few

years. General Wood has already pointed out the way in the cleansing of
Santiago.
The Plague.—One of the most remarkable facts in connection with
modern epidemics has been the revival of the bubonic plague, the most
dreaded of all the great infections. During the present century the disease in
Europe has been confined almost exclusively to Turkey and Southern
Europe. Since 1894, when it appeared at Hong-Kong, it has gradually
spread, and there have been outbreaks of terrible severity in India. It has
extended to certain of the Mediterranean ports, and during the past summer
it reached Glasgow, where there has been a small outbreak. On this
hemisphere there have been small outbreaks in certain of the South
American ports, cases have been brought to New York, and there have been
to November 1st twenty-one cases among the Chinese in San Francisco.
Judging from the readiness with which it has been checked and limited in
Australia, and in particular the facility with which the recent outbreak in
Glasgow has been stamped out, there is very little risk that plague will ever
assume the proportions which gave to it its terrible reputation as the “black
death” of the Middle Ages. As I have already mentioned, the germ is
known, and prophylactic inoculations have been made on a large scale in
India, with a certain measure of success.
Tuberculosis.—In all communities the white plague, as Oliver Wendell
Holmes calls it, takes the first rank as a killing disease. It has been
estimated that of it one hundred and twenty thousand people die yearly in
this country. In all mortality bills tuberculosis of the lungs, or consumption,
heads the list, and when to this is added tuberculosis of the other organs, the
number swells to such an extent that this disease equals in fatality all the
other acute infective diseases combined, if we leave out pneumonia. Less
than twenty years ago we knew little or nothing of the cause of the disease.
It was believed to be largely hereditary. Koch discovered the germ, and with
this have come the possibilities of limiting its ravages.
The following points with reference to it may be stated: In a few very
rare instances the disease is transmitted from parent to child. In a large
proportion of all cases the disease is “caught.” The germs are widely
distributed through the sputum, which, when dry, becomes dust, and is
blown about in all directions. Tubercle bacilli have been found in the dust
of streets, houses, hospital wards, and much-frequented places. A single

individual may discharge from the lungs countless myriads of germs in the
twenty-four hours. Dr. Nuttall estimated from a patient in the Johns
Hopkins Hospital, who had only moderately advanced consumption, that
from one and a half to four and a third billions of germs were thrown off in
the twenty-four hours. The consumptive, as has been well stated, is almost
harmless, and only becomes harmful through bad habits. The germs are
contained in the sputum, which, when dry, is widely scattered in the form of
dust, and constitutes the great medium for the transmission of the disease. If
expectorated into a handkerchief, the sputum dries quickly, particularly if it
is put into the pocket or under the pillow. The beard or mustache of a
consumptive is smeared with the germs. Even in the most careful the hands
are apt to be soiled with the germs, and in those who are dirty and careless
the furniture and materials which they handle readily become infected.
Where the dirty habit prevails of spitting on the floor, a room, or the entire
house, may contain numbers of germs. In the majority of all cases the
infection in tuberculosis is by inhalation. This is shown by the frequency
with which the disease is met in the lungs, and the great prevalence of
tuberculosis in institutions in which the residents are restricted in the matter
of fresh air and a free, open life. The disease prevails specially in cloisters,
in jails, and in asylums. Infection through milk is also possible; it is
doubtful whether the disease is transmitted through meat. So widespread are
the germs that post-mortem examination has shown that a very large
number of persons show slight signs of the disease who have never during
life presented any symptoms; in fact, some recent investigations would
indicate that a very large proportion of all persons at the age of forty have
somewhere in their bodies slight tuberculous lesions. This shows the
importance of the individual predisposition, upon which the older writers
laid so much stress, and the importance of maintaining the nutrition at its
maximum.
One of the most remarkable features of modern protective medicine is
the widespread interest that has been aroused in the crusade against
tuberculosis. What has already been accomplished warrants the belief that
the hopes of even the most enthusiastic may be realized. A positive decline
in the prevalence of the disease has been shown in many of the larger cities
during the past ten years. In Massachusetts, which has been a hot-bed of
tuberculosis for many years, the death-rate has fallen from forty-two per ten
thousand inhabitants in 1853 to twenty-one and eight-tenths per ten

thousand inhabitants in 1895. In the city of Glasgow, in which the records
have been very carefully kept, there has been an extraordinary fall in the
death-rate from tuberculosis, and the recent statistics of New York City
show, too, a similar remarkable diminution.
In fighting the disease our chief weapons are: First, education of the
public, particularly of the poorer classes, who do not fully appreciate the
chief danger in the disease. Secondly, the compulsory notification and
registration of all cases of tuberculosis. The importance of this relates
chiefly to the very poor and improvident, from whom, after all, comes the
greatest danger, and who should be under constant surveillance in order that
these dangers may be reduced to a minimum. Thirdly, the foundation in
suitable localities by the city and by the State of sanatoria for the treatment
of early cases of the disease. Fourthly, provision for the chronic, incurable
cases in special hospitals.
Diphtheria.—Since the discovery of the germ of this disease and our
knowledge of the conditions of its transmission, and the discovery of the
antitoxin, there has been a great reduction in its prevalence and an equally
remarkable reduction in the mortality. The more careful isolation of the
sick, the thorough disinfection of the clothing, the rigid scrutiny of the
milder cases of throat disorder, a more stringent surveillance in the period
of convalescence, and the routine examination of the throats of school-
children—these are the essential measures by which the prevalence of the
disease has been very markedly diminished. The great danger is in the mild
cases, in which the disease has perhaps not been suspected, and in which
the child may be walking about and even going to school. Such patients are
often a source of widespread infection. The careful attention given by
mothers to the teeth and mouth of children is also an important factor. In
children with recurring attacks of tonsillitis, in whom the tonsils are
enlarged, the organs should be removed. Through these measures the
incidence of the disease has been very greatly reduced.
Pneumonia.—While there has been a remarkable diminution in the
prevalence of a large number of all the acute infections, one disease not
only holds its own, but seems even to have increased in its virulence. In the
mortality bills, pneumonia is an easy second to tuberculosis. It attacks
particularly the intemperate, the feeble, and the old, though every year a
large number of robust, healthy individuals succumb. So frequent is

pneumonia at advanced periods of life that to die of it has been said to be
the natural end of old men in this country. In many ways, too, it is a
satisfactory disease, if one may use such an expression. It is not associated
with much pain, except at the onset, the battle is brief and short, and a great
many old persons succumb to it easily and peacefully.
We know the cause of the disease; we know only too well its
symptoms, but the enormous fatality (from twenty to twenty-five per cent.)
speaks only too plainly of the futility of our means of cure, and yet in no
disease has there been so great a revolution in treatment. The patient is no
longer drenched to death with drugs, or bled to a point where the resisting
powers of nature are exhausted. We are not without hope, too, that in the
future an antidote may be found to the toxins of the disease, and of late
there have been introduced several measures of great value in supporting
the weakness of the heart, a special danger in the old and debilitated.
Hydrophobia.—Rabies, a remarkable, and in certain countries a
widespread, disease of animals, when transmitted to a man by the bite of
rabid dogs, wolves, etc., is known as hydrophobia. The specific germ is
unknown, but by a series of brilliant observations Pasteur showed (1) that
the poison has certain fixed and peculiar properties in connection with the
nervous system; (2) that susceptible animals could be rendered refractory to
the disease, or incapable of taking it, by a certain method of inoculation;
and (3) that an animal unprotected and inoculated with a dose of the virus
sufficient to cause the disease may, by the injection of proper anti-rabic
treatment, escape. Supported by these facts, Pasteur began a system of
treatment of hydrophobia in man, and a special institute was founded in
Paris for the purpose. When carried out promptly the treatment is successful
in an immense majority of all cases, and the mortality in persons bitten by
animals proved to be rabid, who have subsequently had the anti-rabic
treatment, has been reduced to less than one-half per cent. The disease may
be stamped out in dogs by careful quarantine of suspected animals, and by a
thoroughly carried out muzzling order.
Malaria.—Among the most remarkable of modern discoveries is the
cause of malarial fever, one of the great maladies of the world, and a prime
obstacle to the settlement of Europeans in tropical regions. Until 1880 the
cause was quite obscure. It was known that the disease prevailed chiefly in
marshy districts, in the autumn, and that the danger of infection was

greatest in the evening and at night, and that it was not directly contagious.
In 1880 a French army surgeon, Laveran, discovered in the red blood-
corpuscles small bodies which have proved to be the specific germ of the
disease. They are not bacteria, but little animal bodies resembling the
amœba—tiny little portions of protoplasm. The parasite in its earliest form
is a small, clear, ring-shaped body inside the red blood-corpuscle, upon
which it feeds, gradually increasing in size and forming within itself
blackish grains out of the coloring matter of the corpuscle. When the little
parasite reaches a certain size it begins to divide or multiply, and an
enormous number of these breaking up at the same time give off poison in
the blood, which causes the paroxysms of fever. During what is known as
the chill, in the intermittent fever, for example, one can always find these
dividing parasites. Several different forms of the parasites have been found,
corresponding to different varieties of malaria. Parasites of a very similar
nature exist abundantly in birds. Ross, an army surgeon in India, found that
the spread of this parasite from bird to bird was effected through the
intervention of the mosquito. The parasites reach maturity in certain cells of
the coats of the stomach of these insects, and develop into peculiar thread-
like bodies, many of which ultimately reach the salivary glands, from
which, as the insect bites, they pass with the secretion of the glands into the
wound. From this as a basis, numerous observers have worked out the
relation of the mosquito to malaria in the human subject.
Briefly stated, the disease is transmitted chiefly by certain varieties of
the mosquito, particularly the Anopheles. The ordinary Culex, which is
present chiefly in the Northern States, does not convey the disease. The
Anopheles sucks the blood from a person infected with malaria, takes in a
certain number of parasites, which undergo development in the body of the
insect, the final outcome of which is numerous small, thread-like structures,
which are found in numbers in the salivary glands. From this point, when
the mosquito bites another individual, they pass into his blood, infect the
system, and in this way the disease is transmitted. Two very striking
experiments may be mentioned. The Italian observers have repeatedly
shown that Anopheles which have sucked blood from patients suffering
from malaria, when sent to a non-malarial region, and there allowed to bite
perfectly healthy persons, have transmitted the disease. But a very crucial
experiment was made a short time ago. Mosquitoes which had bitten
malarial patients in Italy were sent to London and there allowed to bite Mr.

Manson, son of Dr. Manson, who really suggested the mosquito theory of
malaria. This gentleman had not lived out of England, and there is no acute
malaria in London. He had been a perfectly healthy, strong man. In a few
days following the bites of the infected mosquitoes he had a typical attack
of malarial fever.
The other experiment, though of a different character, is quite as
convincing. In certain regions about Rome, in the Campania, malaria is so
prevalent that in the autumn almost every one in the district is attacked,
particularly if he is a new-comer. Dr. Sambron and a friend lived in this
district from the 1st of June to the 1st of September, 1900. The test was
whether they could live in this exceedingly dangerous climate for the three
months without catching malaria, if they used stringent precautions against
the bites of mosquitoes. For this purpose the hut in which they lived was
thoroughly wired, and they slept with the greatest care under netting. Both
of these gentlemen at the end of the period had escaped the disease.
The importance of these studies cannot be overestimated. They explain
the relation of malaria to marshy districts, the seasonal incidence of the
disease, the nocturnal infection, and many other hitherto obscure problems.
More important still, they point out clearly the way by which malaria may
be prevented: First, the recognition that any individual with malaria is a
source of danger in a community, so that he must be thoroughly treated with
quinine; secondly, the importance of the draining of marshy districts and
ponds in which mosquitoes breed; and, thirdly, that even in the most
infected regions persons may escape the disease by living in thoroughly
protected houses, in this way escaping the bites of mosquitoes.
Venereal Diseases.—These continue to embarrass the social economist
and to perplex and distress the profession. The misery and ill-health which
they cause are incalculable, and the pity of it is that the cross is not always
borne by the offender, but innocent women and children share the penalties.
The gonorrhœal infection, so common, and often so little heeded, is a cause
of much disease in parts other than those first affected. Syphilis claims its
victims in every rank of life, at every age, and in all countries. We now treat
it more thoroughly, but all attempts to check its ravages have been fruitless.
Physicians have two important duties: the incessant preaching of continence
to young men, and scrupulous care, in every case, that the disease may not
be a source of infection to others, and that by thorough treatment the patient

may be saved from the serious late nervous manifestations. We can also
urge that in the interests of public health venereal diseases, like other
infections, shall be subject to supervision by the State. The opposition to
measures tending to the restriction of these diseases is most natural: on the
one hand, from women, who feel that it is an aggravation of a shocking
injustice and wrong to their sex; on the other, from those who feel the moral
guilt in a legal recognition of the evil. It is appalling to contemplate the
frightful train of miseries which a single diseased woman may entail, not
alone on her associates, but on scores of the innocent—whose bitter cry
should make the opponents of legislation feel that any measures of
restriction, any measures of registration, would be preferable to the present
disgraceful condition, which makes of some Christian cities open brothels
and allows the purest homes to be invaded by the most loathsome of all
diseases.
Leprosy.—Since the discovery of the germ of this terrible disease
systematic efforts have been made to improve the state of its victims and to
promote the study of the conditions under which the disease prevails. The
English Leprosy Commission has done good work in calling attention to the
widespread prevalence of the disease in India and in the East. In this
country leprosy has been introduced into San Francisco by the Chinese, and
into the Northwestern States by the Norwegians, and there are foci of the
disease in the Southern States, particularly Louisiana, and in the province of
New Brunswick. The problem has an additional interest since the
annexation of Hawaii and the Philippine Islands, in both of which places
leprosy prevails extensively. By systematic measures of inspection and the
segregation of affected individuals the disease can readily be held in check.
It is not likely ever to increase among native Americans, or again gain such
a foothold as it had in the Middle Ages.
Puerperal Fever.—Perhaps one of the most striking of all victories of
preventive medicine has been the almost total abolition of so-called child-
bed fever from the maternity hospitals and from private practice. In many
institutions the mortality after child-birth was five or six per cent., indeed
sometimes as high as ten per cent., whereas to-day, owing entirely to proper
antiseptic precautions, the mortality has fallen to three-tenths to four-tenths
per cent. The recognition of the contagiousness of puerperal fever was the
most valuable contribution to medical science made by Oliver Wendell

Holmes. There had been previous suggestions by several writers, but his
essay on the “Contagiousness of Puerperal Fever,” published in 1843, was
the first strong, clear, logical statement of the case. Semmelweis, a few
years later, added the weight of a large practical experience to the side of
the contagiousness, but the full recognition of the causes of the disease was
not reached until the recent antiseptic views had been put into practical
effect.

THE NEW DISPENSATION IN TREATMENT

The century has witnessed a revolution in the treatment of disease, and
the growth of a new school of medicine. The old schools—regular and
homœopathic—put their trust in drugs, to give which was the alpha and the
omega of their practice. For every symptom there were a score or more of
medicines—vile, nauseous compounds in one case; bland, harmless
dilutions in the other. The new school has a firm faith in a few good, well-
tried drugs, little or none in the great mass of medicines still in general use.
Imperative drugging—the ordering of medicine in any and every malady—
is no longer regarded as the chief function of the doctor. Naturally, when the
entire conception of the disease was changed, there came a corresponding
change in our therapeutics. In no respect is this more strikingly shown than
in our present treatment of fever—say, of the common typhoid fever.
During the first quarter of the century the patients were bled, blistered,
purged and vomited, and dosed with mercury, antimony, and other
compounds to meet special symptoms. During the second quarter, the same,
with variations in different countries. After 1850 bleeding became less
frequent, and the experiments of the Paris and Vienna schools began to
shake the belief in the control of fever by drugs. During the last quarter
sensible doctors have reached the conclusion that typhoid fever is not a
disease to be treated with medicines, but that in a large proportion of all
cases diet, nursing, and bathing meet the indications. There is active,
systematic, careful, watchful treatment, but not with drugs. The public has
not yet been fully educated to this point, and medicines have sometimes to
be ordered for the sake of the friends, and it must be confessed that there

are still in the ranks antiques who would insist on a dose of some kind
every few hours.
The battle against poly-pharmacy, or the use of a large number of drugs
(of the action of which we know little, yet we put them into bodies of the
action of which we know less), has not been fought to a finish. There have
been two contributing factors on the side of progress—the remarkable
growth of the skeptical spirit fostered by Paris, Vienna, and Boston
physicians, and, above all, the valuable lesson of homœopathy, the
infinitesimals of which certainly could not do harm, and quite as certainly
could not do good; yet nobody has ever claimed that the mortality among
homœopathic practitioners was greater than among those of the regular
school. A new school of practitioners has arisen which cares nothing for
homœopathy and less for so-called allopathy. It seeks to study, rationally
and scientifically, the action of drugs, old and new. It is more concerned that
a physician shall know how to apply the few great medicines which all have
to use, such as quinine, iron, mercury, iodide of potassium, opium, and
digitalis, rather than a multiplicity of remedies the action of which is
extremely doubtful.
The growth of scientific pharmacology, by which we now have many
active principles instead of crude drugs, and the discovery of the art of
making medicines palatable, have been of enormous aid in rational practice.
There is no limit to the possibility of help from the scientific investigation
of the properties and action of drugs. At any day the new chemistry may
give to us remedies of extraordinary potency and of as much usefulness as
cocaine. There is no reason why we should not even in the vegetable world
find for certain diseases specifics of virtue fully equal to that of quinine in
the malarial fevers.
One of the most striking characteristics of the modern treatment of
disease is the return to what used to be called the natural methods—diet,
exercise, bathing, and massage. There probably never has been a period in
the history of the profession when the value of diet in the prevention and
the cure of disease was more fully recognized. Dyspepsia, the besetting
malady of this country, is largely due to improper diet, imperfectly prepared
and too hastily eaten. One of the great lessons to be learned is that the
preservation of health depends in great part upon food well cooked and
carefully eaten. A common cause of ruined digestion, particularly in young

girls, is the eating of sweets between meals and the drinking of the
abominations dispensed in the chemists’ shops in the form of ice-cream
sodas, etc. Another frequent cause of ruined digestion in business men is the
hurried meal at the lunch-counter. And a third factor, most important of all,
illustrates the old maxim, that more people are killed by over eating and
drinking than by the sword. Sensible people have begun to realize that
alcoholic excesses lead inevitably to impaired health. A man may take four
or five drinks of whiskey a day, or even more, and thinks perhaps that he
transacts his business better with that amount of stimulant; but it only too
frequently happens that early in the fifth decade, just as business or political
success is assured, Bacchus hands in heavy bills for payment, in the form of
serious disease of the arteries or of the liver, or there is a general
breakdown. With the introduction of light beer there has been not only less
intemperance, but a reduction in the number of the cases of organic disease
of the heart, liver, and stomach caused by alcohol. While temperance in the
matter of alcoholic drinks is becoming a characteristic feature of
Americans, intemperance in the quantity of food taken is almost the rule.
Adults eat far too much, and physicians are beginning to recognize that the
early degenerations, particularly of the arteries and of the kidneys, leading
to Bright’s disease, which were formerly attributed to alcohol, are due in
large part to too much food.
Nursing.—Perhaps in no particular does nineteenth-century practice
differ from that of the preceding centuries more than in the greater attention
which is given to the personal comfort of the patient and to all the
accessories comprised in the art of nursing. The physician has in the trained
nurse an assistant who carries out his directions with a watchful care, and
who is on the lookout for danger-signals, and with accurate notes enables
him to estimate the progress of a critical case from hour to hour. The
intelligent, devoted women who have adopted the profession of nursing, are
not only in their ministrations a public benefaction, but they have lightened
the anxieties which form so large a part of the load of the busy doctor.
Massage and Hydrotherapy have taken their places as most important
measures of relief in many chronic conditions, and the latter has been
almost universally adopted as the only safe means of combating the high
temperatures of the acute fevers.

Within the past quarter of a century the value of exercise in the
education of the young has become recognized. The increase in the means
of taking wholesome out-of-door exercise is remarkable, and should show
in a few years an influence in the reduction of the nervous troubles in young
persons. The prophylactic benefit of systematic exercise, taken in
moderation by persons of middle age, is very great. Golf and the bicycle
have in the past few years materially lowered the average incomes of the
doctors in this country as derived from persons under forty. From the senile
contingent—those above this age—the average income has for a time been
raised by these exercises, as a large number of persons have been injured by
taking up sports which may be vigorously pursued with safety only by those
with young arteries.
Of three departures in the art of healing, brief mention may be made.
The use of the extracts of certain organs (or of the organs themselves) in
disease is as old as the days of the Romans, but an extraordinary impetus
has been given to the subject by the discovery of the curative powers of the
extract of the thyroid gland in the diseases known as cretinism and
myxœdema. The brilliancy of the results in these diseases has had no
parallel in the history of modern medicine, but it cannot be said that in the
use of the extracts of other organs for disease the results have fulfilled the
sanguine expectations of many. There was not, in the first place, the same
physiological basis, and practitioners have used these extracts too
indiscriminately and without sufficient knowledge of the subject.
Secondly, as I have already mentioned, we possess a sure and certain
hope that for many of the acute infections antitoxins will be found.
A third noteworthy feature in modern treatment has been a return to
psychical methods of cure, in which faith in something is suggested to the
patient. After all, faith is the great lever of life. Without it, man can do
nothing; with it, even with a fragment, as a grain of mustard-seed, all things
are possible to him. Faith in us, faith in our drugs and methods, is the great
stock in trade of the profession. In one pan of the balance, put the
pharmacopœias of the world, all the editions from Dioscorides to the last
issue of the United States Dispensatory; heap them on the scales as did
Euripides his books in the celebrated contest in the “Frogs”; in the other put
the simple faith with which from the days of the Pharaohs until now the
children of men have swallowed the mixtures these works describe, and the

bulky tomes will kick the beam. It is the aurum potabile, the touchstone of
success in medicine. As Galen says, confidence and hope do more good
than physic—“he cures most in whom most are confident.” That strange
compound of charlatan and philosopher, Paracelsus, encouraged his patients
“to have a good faith, a strong imagination, and they shall find the effects”
(Burton). While we often overlook or are ignorant of our own faith-cures,
doctors are just a wee bit too sensitive about those performed outside our
ranks. They have never had, and cannot expect to have, a monopoly in this
panacea, which is open to all, free as the sun, and which may make of every
one in certain cases, as was the Lacedemon of Homer’s day, “a good
physician out of Nature’s grace.” Faith in the gods or in the saints cures
one, faith in little pills another, hypnotic suggestion a third, faith in a plain,
common doctor a fourth. In all ages the prayer of faith has healed the sick,
and the mental attitude of the suppliant seems to be of more consequence
than the powers to which the prayer is addressed. The cures in the temples
of Æsculapius, the miracles of the saints, the remarkable cures of those
noble men, the Jesuit missionaries, in this country, the modern miracles at
Lourdes and at St. Anne de Beaupré in Quebec, and the wonder-workings of
the so-called Christian Scientists, are often genuine, and must be considered
in discussing the foundations of therapeutics. We physicians use the same
power every day. If a poor lass, paralyzed, apparently, helpless, bed-ridden
for years, comes to me, having worn out in mind, body, and estate a devoted
family; if she in a few weeks or less by faith in me, and faith alone, takes up
her bed and walks, the saints of old could not have done more. St. Anne and
many others can scarcely to-day do less. We enjoy, I say, no monopoly in
the faith business. The faith with which we work, the faith, indeed, which is
available to-day in every-day life, has its limitations. It will not raise the
dead; it will not put in a new eye in place of a bad one (as it did to an
Iroquois Indian boy for one of the Jesuit fathers), nor will it cure cancer or
pneumonia, or knit a bone; but, in spite of these nineteenth-century
restrictions, such as we find it, faith is a most precious commodity, without
which we should be very badly off.
Hypnotism, introduced by Mesmer in the eighteenth century, has had
several revivals as a method of treatment during the nineteenth century. The
first careful study of it was made by Braid, a Manchester surgeon, who
introduced the terms hypnotism, hypnotic, and nervous sleep; but at this
time no very great measure of success followed its use in practice, except

perhaps in the case of an Anglo-Indian surgeon, James Esdaile, who, prior
to the introduction of anæsthesia, had performed two hundred and sixty-one
surgical operations upon patients in a state of hypnotic unconsciousness.
About 1880 the French physicians, particularly Charcot and Bernheim, took
up the study, and since that time hypnotism has been extensively practised.
It may be defined as a subjective psychical condition, what Braid called
nervous sleep, resembling somnambulism, in which, as Shakespeare says,
in the description of Lady Macbeth, the person receives at once the benefit
of sleep and does the effects or acts of watching or waking. Therapeutically,
the important fact is that the individual’s natural susceptibility to suggestion
is increased, and this may hold after the condition of hypnosis has passed
away. The condition of hypnosis is usually itself induced by suggestion,
requesting the subject to close the eyes, to think of sleep, and the operator
then repeats two or three times sentences suggesting sleep, and suggesting
that the limbs are getting heavy and that he is feeling drowsy. During this
state it has been found that the subjects are very susceptible to suggestion.
Too much must not be expected of hypnotism, and the claims which have
been made for it have been too often grossly exaggerated. It seems, as it has
been recently well put, that hypnotism “at best permits of making
suggestions more effective for good or bad than can be done upon one in his
waking state.” It is found to be of very little use in organic disease. It has
been helpful in some cases of hysteria, in certain functional spasmodic
affections of the nervous system, in the vicious habits of childhood, and in
suggesting to the victims of alcohol and drugs that they should get rid of
their inordinate desires. It has been used successfully in certain cases for the
relief of labor pains, and in surgical operations; but on the whole, while a
valuable agent in a few cases, it has scarcely fulfilled the expectations of its
advocates. It is a practice not without serious dangers, and should never be
performed except in the presence of a third person, and its indiscriminate
practice by ignorant persons should be prevented by law.
One mode of faith-healing in modern days, which passes under the
remarkable name of Christian Science, is probably nothing more than
mental suggestion under another name. “The patient is told to be calm, and
is assured that all will go well; that he must try to aid the healer by
believing that what is told him is true. The healer then, quietly but firmly,
asserts and reiterates that there is no pain, no suffering, that it is
disappearing, that relief will come, that the patient is getting well.” This is

precisely the method which Bernheim used to use with such success in his
hypnotic patients at Nancy, iterating and reiterating, in a most wearisome
way, that the disease would disappear and the patient would feel better. As
has been pointed out by a recent writer (Dr. Harry Marshall), the chief basis
for the growth of Christian Science is that which underlies every popular
fallacy: “Oliver Wendell Holmes outlined very clearly the factors
concerned, showing (a) how easily abundant facts can be collected to prove
anything whatsoever; (b) how insufficient ‘exalted wisdom, immaculate
honesty, and vast general acquirements’ are to prevent an individual from
having the most primitive ideas upon subjects out of his line of thought;
and, finally, demonstrating ‘the boundless credulity and excitability of
mankind upon subjects connected with medicine.’”

William Osler.

SURGERY

T heremarkable
end of the eighteenth century was made notable by one of the most
and beneficent discoveries which has ever blessed the
human race, the discovery of the means of preventing small-pox. On May
14, 1796, Dr. Edward Jenner inoculated James Phipps. When we remember
that two million persons died in a single year in the Russian Empire from
small-pox; that in 1707 in Iceland, out of a population of thirty thousand,
sixty per cent., or eighteen thousand, died; that in Jenner’s time “an adult
person who had not had small-pox was scarcely met with or heard of in the
United Kingdom, and that owing to his discovery small-pox is now one of
the rarest diseases,” the strong words I have used seem fully justified. But
the eighteenth century was not to witness the end of progress in medicine.
The advances in the nineteenth century have been even more startling and
more beneficent. What these advances have been in the department of
medicine has been related by Professor Osler. It is my province to speak
only of surgery.

METHOD OF TEACHING

The first advance which should be mentioned is a fundamental one—
namely, methods of medical teaching. At the beginning of the nineteenth
century there were only three medical schools in the United States: the
Medical Department of the University of Pennsylvania, established in 1765;
the Medical Department of Harvard, established in 1783; and the Medical
Department of Dartmouth, established in 1797. The last report of the
Commissioner of Education gives a list of one hundred and fifty-five
medical schools now in existence in this country, many of them still poorly

equipped and struggling for existence, but a large number of them standing
in the first rank, with excellent modern equipment, both in teachers,
laboratories, hospitals, and other facilities. The medical curriculum then
extended over only two years or less, and consisted of courses of lectures at
the most by seven professors who, year after year, read the same course of
lectures, without illustrations and with no practical teaching. The medical
schools, even when connected with universities, were practically private
corporations, the members of which took all the fees, spent what money
they were compelled to spend in the maintenance of what we now should
call the semblance of an education, and divided the profits. Until within
about twenty years this method prevailed in all our medical schools. But the
last two decades of the century have seen a remarkable awakening of the
medical profession to the need of a broader and more liberal education, and
that, as a prerequisite, the medical schools should be on the same basis as
the department of arts in every well-regulated college. To accomplish this
the boards of trustees have taken possession of the fees of students, have
placed the faculties upon salaries, and have used such portion of the
incomes of the institutions as was needed for a constant and yet rapid
development along the most liberal lines.

COLLEGE HOSPITALS

The first step has been the establishment in connection with most
schools of general hospitals in which the various teachers in the college
should be the clinical instructors, and where the students would have the
means not only of hearing theoretically what should be done to the sick, but
of actually examining the patients under the supervision of their instructors,
studying the cases so as to become skilled in reaching a diagnosis and
indicating what in their opinion was necessary in the way either of hygiene,
medicine, or surgical operation. More than that, in most of the advanced
schools to-day the students assist the clinical faculties of the hospitals in the
actual performance of operations, so that when they graduate they are
skilled to a degree utterly unknown twenty years ago.

ESTABLISHMENT OF LABORATORIES

Another step which was equally important, and in some respects even
more so, has been the establishment of laboratories connected with each
branch of instruction. A laboratory of anatomy (the dissecting room) every
medical school has always had, but all the other laboratories are recent
additions. Among these may be named a laboratory of clinical medicine, a
laboratory of therapeutics, in which the action of drugs is studied; a
laboratory of chemistry, a laboratory of microscopy, a laboratory of
pathology for the study of diseased tissues, a laboratory of embryology for
the study of the development of the human body and of the embryos of
animals, a laboratory of hygiene, a laboratory of bacteriology, a laboratory
of pharmacy, a surgical laboratory, in which all the operations of surgery are
done on the cadaver by each student, a laboratory of physiology, and in
many colleges private rooms in which advanced work may be done for the
discovery of new truths.
In all these laboratories, instead of simply hearing about the
experiments and observations, each student is required to handle the drugs,
the chemicals, the apparatus, to do all the operations, to look through the
microscope, etc.; in other words, to do all that which is necessary for the
proper understanding of the case in hand. In fact, it may be said that in view
of the opportunities and the requirements of modern hospitals, it is
undoubtedly true that a hospital patient, the poorest of the poor, often has
his case more thoroughly studied and more accurately observed than the
wealthy patient who is attended at his home. On the other hand, however, so
many laboratories with their expensive apparatus and a large staff of
assistants mean an enormous increase in the expense of a medical
education, for which the student does not pay anything like an equivalent.
Hence the need in all of our best modern medical schools for endowments,
in order that such work may be carried on properly, and yet the student not
be charged such fees as to be practically prohibitory, excepting for the rich,
or at the least the well-to-do. I do not hesitate to say that at the end of the
second year many a diligent student of to-day is better fitted to practise
medicine than was the graduate of half a century ago.

ANATOMICAL MATERIAL

One of the most important means of the study of medicine, and
especially of surgery, is a thorough acquaintance with the anatomy of the
human body. No one would think of placing an engineer in charge of a
complicated piece of machinery, who had never become intimately
acquainted with all the parts of such a machine, so that he could take it to
pieces and put it together again with ease and intelligence. Yet, until
comparatively recently, this knowledge of anatomy was both required of,
and yet at the same time the means of obtaining it was forbidden to, the
medical student. If he performed an operation and was guilty of negligence
or error, due to his want of anatomical knowledge, he was liable to a suit for
malpractice. Yet his only means of becoming acquainted with the anatomy
of the human body was by stealing the bodies of the dead. In England, up to
1832, this was equally true. A regular traffic in human bodies existed there
as well as here, and, by reason of its perils, the cost of bodies for dissection
was very great; but it was only a question of money. In his testimony before
the Parliamentary Committee, Sir Astley Cooper made a shiver run down
the backs of the noble lords who listened to him when he said that in order
to dissect the body of any of them it was only necessary for him to pay
enough. The large pecuniary profits of such business, when the supply was
very small, led to the horrible atrocities of Burke and Hare in Edinburgh in
1832. They deliberately murdered a considerable number of persons, and
sold the bodies to the dissecting rooms in that city. The discovery of their
crimes finally led to the passage of the Anatomy Act, which has been in
force in Great Britain ever since. Similar violations of graveyards in this
country have led to the passage in various States of somewhat similar laws,
usually giving for dissection the bodies of those who were so poor in
friendship that no one would spend the money necessary for their burial.
Even to-day, in a large number of our States, the former anomalous
condition of affairs exists. The increase of anatomical material which has
resulted from the enactment of wise and salutary laws for this purpose has
given a great impetus to the study of anatomy, and has produced a far better
educated class of physicians in most parts of the United States within the
last few years. The enlightened sense of the community has perceived that
to deny the medical schools the means of properly teaching anatomy was a
fatal mistake, and resulted in an ignorance of which the community were

the victims. As a result, it is possible now, by law, in most States to obtain a
reasonable number of cadavers, not only for the study of anatomy, but for
the performance of all the usual operations.

MEDICAL LIBRARIES

Along with this there has been throughout this country a marked
movement in favor of medical libraries. It is to the credit of the government
of the United States that the whole world is debtor to us, not only for the
foremost medical library in the world, that of the surgeon-general of the
army in Washington, but also for the magnificent index-catalogue, not only
of the books, but all the journal articles in every language in the world. No
better investment of money was ever made than the establishment of this
library, and its allied museum, and the publication of the index-catalogue.

EMBRYOLOGY

As a result of all these means and methods of study, and as a part of the
great educational and scientific movement of the century, medical men now
take a wholly different view of the normal and abnormal structures of the
human body. The study of embryology has shown us that many of the
deviations from the normal development of the human body are easily
explained by embryology. One of the most important changes in our idea,
for example, of tumors is due to the fact that the study of embryology and
of the tissues of the embryo have shown us that diseased structures, which
lack explanation entirely, when compared with the adult human tissues,
readily find their explanation and fall into an unexpected order when
compared with the tissues of the embryo. Not only, however, has the study
of embryological tissues thrown a flood of light on diseased structures, but
we have obtained new views of the relation of man to all creatures, lower in
the scale of life. Largely owing to the doctrine of evolution, we now
recognize the fact that, so far as his body is concerned, man is kindred to
the brutes; that his diseases, within certain limitations, are identical with
similar diseases of the lower animals; that his anatomy and physiology are,

in essence, the same as the anatomy and physiology of the lower animals,
even the very lowest, and that many of his diseases can be best studied in
the lower animals, because upon them we can make exact experiments
which would be impossible in man. While it is true that each animal has
disorders which are peculiar to itself, and that it is not subject to some of
the disorders to which man is a victim, and, per contra, that man is a victim
to some disorders from which animals do not suffer, yet, taking them as a
whole, the diseases of man and of animals, and the action of remedies on
both, are practically identical. To this I shall have occasion to refer again.

PATHOLOGY

Among the laboratories which I mentioned, one of the most important
is that of pathology and morbid anatomy, or the study of diseased tissues
and organs. The first work on pathology written in this country was by one
of our best-known surgeons, the late Samuel D. Gross, and one of his most
important contributions to surgical progress consisted in his persistent
advocacy of the need for the study of pathology as a basis for all our means
of cure. This is evident, if we consider the illustration I used a moment ago
of a steam-engine. Unless he knows precisely the defects of such a
machine, the influence of fresh or salt water on a boiler, the influence of
rust, the effect of oils, entirely apart from the mere mechanism of the
engine, an engineer might make the most serious mistake, resulting in fatal
damage, both to the machine and probably to life. So, surgical pathology is
the study of the processes of disease, the alterations in the minute structure
of tissues and organs, without which no surgeon can be fitted for his task,
much less can he be called an accomplished surgeon. All of these
laboratories mark the difference between the scientific and the empirical
method. The old student of medicine went from case to case, heard many a
good maxim, and learned many a useful trick; but, after all, it was only an
empirical knowledge which he obtained. It did not go to the foundation of
things, it was not scientific, as is the collegiate instruction of to-day.
Having now glanced rapidly at the improvement in medical instruction,
let me turn next to a few of the principal discoveries which have made the
surgery of to-day so much superior to the surgery of a hundred years ago.

ANÆSTHESIA

After vaccination, the most important medical event of the century is
the discovery of anæsthesia. While there were some prior attempts at
anæsthesia, practically it dates from October 16, 1846, when Dr. John C.
Warren, in the Massachusetts General Hospital, first performed a major
surgical operation, without inflicting the slightest pain. I cannot enter into
the merits of the various claimants for the credit of first using an anæsthetic,
but ether was then for the first time publicly administered by Morton, and
the very sponge which was then used is now a precious trophy of the
Massachusetts General Hospital. I may, perhaps, quote from an address
which I delivered before the Medical and Chirurgical Faculty of the State of
Maryland, at their centennial anniversary, in April, 1899, the following in
relation to anæsthesia:

“The news went like wildfire, and anæsthesia was soon
introduced into every clinic and at almost every operation
throughout the civilized world. Prior to that time a surgical
operation was attended with horrors which those who live in these
days cannot appreciate. He was the best surgeon who could perform
any operation in the least possible time. The whole object of new
methods of operating was to shorten the period of frightful agony
which every patient had to endure. Every second of suffering saved
was an incalculable boon. To submit to any operation required then
a heroism and an endurance which is almost incomprehensible to us
now. All of the more modern, deliberate, careful, painstaking
operations, involving minute dissection, amid nerves and blood-
vessels, when life or death depends on the accuracy of almost every
touch of the knife, were absolutely impossible. It was beyond
human endurance quietly to submit one’s self for an hour, for an
hour and a half, for two hours, or even longer, to such physical
agony.
“It is a striking commentary on the immediate results of
anæsthesia to learn that, in five years before the introduction of
ether, only one hundred and eighty-four persons were willing to
submit themselves to such a dreadful ordeal in the Massachusetts
General Hospital—an average of thirty-seven operations per annum,

or three per month.... During the last year, in the same hospital—a
Mecca for every surgeon the world over—over thirty-seven hundred
operations were performed. It is not an uncommon thing at the
present day for any one of the more active surgeons of this country
to do as many as four or five hundred operations in a year. I have
known as many as nineteen operations to be done in the Jefferson
Medical College Hospital in a single day—equalling six months’
work in Boston before the introduction of ether.”

The next year, 1847, witnessed the introduction of chloroform by Sir
James Y. Simpson, of Edinburgh. Until I became acquainted with the
striking figures just quoted, I had often wondered at the hospital scene in
that most touching story, Rab and His Friends, by the late gifted and well-
beloved physician, Dr. John Brown, of Edinburgh. Nowadays students do
not rush into the surgical amphitheatre when they learn that an operation is
to be done, but it is taken as a matter of course, for practically every day
many operations are done in most of our large hospitals. But, at the time
when Rab’s mistress was operated upon, an operation, as has been stated,
was a very rare event. Few had the fortitude to endure its dreadful pangs.
Now, thanks to the blessed sleep of anæsthesia, sufferers from even the
most dreadful disorders can have long and difficult operations done,
accurate and tedious dissections made, and yet feel not a twinge of pain.
Besides general anæsthesia by ether, chloroform, and a few other
agents, there have been introduced several means for producing “local
anæsthesia,” i.e., agents which destroy the sensibility of the part of the body
to be operated upon while not producing unconsciousness. Freezing the part
by ice and salt, or by a quickly evaporating spray of rhigolene or chloride of
ethyl, are sometimes used. But cocaine and a somewhat similar substance,
eucaine, have of late been more extensively used on man, after their
harmlessness had been first shown by experiments on animals. In 1885
Corning, of New York, injected a solution of cocaine as near to the spinal
cord as was possible, and produced insensibility of all the body below the
point of injection by the effect of the cocaine upon the spinal cord. A few
years ago Quincke, of Kiel, in Germany, devised a means of puncturing the
spinal canal itself in the lumbar region (the lowest part of the small of the
back) for the purpose of drawing off some of the fluid for examination. This
suggested to Bier, then of Kiel, who was apparently ignorant of Corning’s

work, that cocaine could be injected through a hollow needle inserted into
the spinal canal by “lumbar puncture” and so produce anæsthesia of all the
body below this point. This method was published by him in 1899, and was
soon repeated in America. In France, however, it has been practised more
than elsewhere, Tupper, of Paris, having successfully done over two
hundred operations by “spinal anæsthesia.” All of the body below the
diaphragm can thus be deprived of sensibility. The method will probably
never replace ether and chloroform, but in many cases is a valuable aid to
the surgeon. But it has its dangers and its inconveniences. The ideal
anæsthetic is not that which destroys sensibility and yet leaves the patient
perfectly conscious, as spinal anæsthesia does. A patient to whom I recently
proposed it for certain special reasons rejected it, saying, with probable
truth, that she could never bear the strain of lying on the table perfectly
conscious of all that was being done and frightened by any surgical
emergency which might easily arise in such a long, difficult, and dangerous
operation. The ideal anæsthetic is that which will abolish pain and
consciousness without danger to life. The twentieth century will
undoubtedly see the discovery of this safe and efficient anæsthetic.

ANTISEPSIS

But the limits of surgical progress were not yet reached. Let me quote
again from the address before alluded to:

“Even the introduction of anæsthesia, however, did not rid
surgery of all its terrors. The acute pain of the operation was
abolished, but the after-suffering, as I know only too well, in my
early surgical days, was something dreadful to see. The parched lips
of the poor sufferer, tossing uneasily during sleepless nights;
wounds reeking with pus, and patients dying by scores from blood-
poisoning, from erysipelas, from tetanus, from gangrene, were only
too familiar sights in the pre-antiseptic days. Then, again, there
arose one of these deliverers of the human race whose name can
never be forgotten and whose fame will last so long as time shall
endure. Jenner, Warren, and Lister are a triumvirate of names of
which any profession may well be proud. Thank God, they all

sprang from virile Anglo-Saxon loins! No praise, no reward, no
fame is too great for them. That Lord Lister still lives to see the
triumph of his marvellous services to humanity is a joy to all of us.
And when the profession arose en masse, within the last few years,
at the International Congress of Berlin, and at the meeting of the
British Medical Association in Montreal, and welcomed him with
cheer after cheer, it was but a feeble expression of gratitude for
benefits which no words can express.
“Before Lister’s day erysipelas, tetanus, gangrene, and blood-
poisoning in its various phases were the constant attendant of every
surgeon. They were dreaded guests at almost any operation; and
when in rare cases we obtained primary union without a drop of pus,
without fever, and with but little suffering, it was a marvellous
achievement. Now it is precisely reversed. The surgeon who does
not get primary union without a drop of pus, with no fever, and with
little suffering, asks himself—what was the fault in my technic? To
open the head, the abdomen, or the chest thirty years ago was
almost equivalent to signing the death-warrant of a patient. The
early mortality of ovariotomy was about sixty per cent.; two out of
three died. Now many a surgeon can point to a series of one hundred
abdominal operations with a fatality of only two or three per cent.
When Sir Spencer Wells recorded his first one thousand cases of
ovariotomy it was calculated that after deducting the years which
the patients who died from the operation would have lived had no
operation been done the net result of the thousand cases was an
addition of twenty thousand years to human life. One thousand
ovariotomies under antiseptic precautions at the present would
certainly add at least thirty thousand years to human life. Would not
such a guerdon be enough for any man?
“This, too, is a direct result of laborious laboratory researches,
beginning with the investigations of Liebig and Pasteur on
fermentation. Lister went still further. Even before the discovery of
the bacteria of suppuration, of tetanus, and of erysipelas he showed
us experimentally how, by surgical cleanliness, we could avoid all
infection and so banish these pests from our hospitals and bring life

and health to many who otherwise would have perished from
operations which are now perfectly safe.
“The mortality of compound fractures in the pre-antiseptic days
was about sixty per cent. It was one of the most dreaded of all
accidents. Its mortality now is perhaps not over three per cent., and
the mortality from sepsis after such a fracture, in the hands of well-
instructed surgeons, is almost nil. Prior to Lister’s day the mortality
of major amputations varied from fifty to sixty-three per cent. Now
it is from ten to twenty per cent. And so I might go on with
operation after operation and show how they have become so safe
that one need not dread any, saving exceptional cases.
“These two modern discoveries, anæsthesia and antisepsis, have
utterly revolutionized modern surgery. They have made possible
operations which, by reason of their length and pain and danger,
were utterly unjustifiable in former days, but are now the daily
occupation of a busy surgeon. And, far better than this, they have
enabled us to bring to homes and hearts, which otherwise would
have been broken up and wrung with sorrow, the comfort of life
restored to dear ones upon whom depended the happiness and
support of the families. Translate figures into happy hearts and
prosperous homes if you can, and then you can tell me what Warren
and Lister have done for humanity!”

The result of these two wonderful discoveries has been to separate us
from the surgical past, as by a great gulf.

“Great theologians, such as a Calvin or a Jonathan Edwards,
were they recalled to life, could discourse as learnedly as ever of
predestination and free will; great preachers, as a Beecher or a
Spurgeon, could stir our souls and warm our hearts as of old; great
jurists, as a Justinian or a Marshall, could expound the same
principles of law which hold good for all time; great forensic
orators, as a Burke or a Webster, could convince us by the same
arguments and arouse us by the same invectives or the same
eloquence that made our fathers willing captives to their silver
tongues. But to-day, so rapid has been our surgical progress, a

Velpeau, a Sir William Ferguson, or a Pancoast, all of whom have
died within the last thirty years, could not teach modern surgical
principles nor perform a modern surgical operation. Even our every-
day surgical vocabulary—staphylococcus, streptococcus, infection,
immunity, antisepsis and asepsis, toxin and antitoxin—would be
unintelligible jargon to him; and our modern operations on the
brain, the chest, the abdomen, and the pelvis would make him
wonder whether we had not lost our senses, until, seeing the almost
uniform and almost painless recoveries, he would thank God for the
magnificent progress of the last half-century, which had vouchsafed
such magical, nay, such almost divine, power to the modern
surgeon.”

THE SURGERY OF WAR

One of the immediate consequences of the introduction of the antiseptic
method has been a remarkable mitigation of the horrors of war. Our recent
war with Spain has proved, and the present military operations in the
Philippines and of the British in South Africa will still further prove, its
advantages. Witness a little book written by Professor von Esmarch, of
Kiel, Germany, with the apt title, The Fight of Humanity Against the
Horrors of War; with an appendix, entitled, “The Samaritan on the Battle-
field.” One of the most valuable means for the preservation of human life is
carried by every soldier in a modern civilized army as a part of his
regulation outfit, a “First Aid Package” for the treatment of any wound or
injury; and one of the most valuable and interesting papers read before the
American Surgical Association, at its meeting in Chicago in 1899, was by
Professor Senn on the “First Aid Package.” This first aid package contains
an antiseptic dressing, which can be applied to all but the gravest wounds
for the purpose of preventing infection, which is the principal danger to life
after accident or injury. The universal testimony of our surgeons in Cuba
was that by its use most wounds were prevented from becoming infected,
and, therefore, inflamed, and that the number of operations was greatly
diminished by reason of its use.

BACTERIOLOGY

In experimental science, two methods of progress are observed; first, in
actual practice certain methods are adopted because they are found to be the
most advantageous and useful, though we cannot explain why it is so—i.e.,
practice outstrips theory. Again, as a result of experimental investigation,
certain facts are discovered which explain why the practical methods just
alluded to are the best, and this in turn suggests further improvements in our
practice—i.e., theory outstrips practice and enlarges its domain. Thus
outstripping theory, the practical advance made by Lister was an example of
the first. His striking results in turn stimulated scientific observers to make
new discoveries of the greatest importance, and thus science immensely
improved and widened our practical methods.
No definite year or day can be assigned as the birth-date of Lord
Lister’s antiseptic methods, as we can, for instance, for vaccination or for
anæsthesia. We may assume, at least for this counrty, the summer of 1876
as the starting-point. During that year Lord Lister attended the International
Medical Congress held in Philadelphia, and demonstrated his then methods
and convinced a few surgeons of their immense advantages. Even before
that date there had been very many experiments and observations,
especially on the blood. In 1863 Davaine, in France, had discovered little
rod-like bodies in the blood in wool-sorters’ disease, or anthrax, which he
named from their shape “bacteria,” or “little rods.” This name has been
adopted for all forms of germs, though many of them are not rod-like in
their shape. Not until 1881 was the cause of inflammation and suppuration
(the formation of pus or “matter”) discovered. In that year Ogston, of
Aberdeen, published experiments which he believed demonstrated the fact
that certain bacteria were the cause of suppuration. Since then this has been
amply confirmed not only by experiments upon animals, but by observation
in man. In 1882 Robert Koch, of Berlin, discovered the cause of
tuberculosis, a little rod-like body, which is named the “bacillus” of
tuberculosis. In 1883 Fehleisen discovered the germ of erysipelas, and in
1887 Nicolaier and Rosenbaum discovered the bacillus of tetanus or
lockjaw. So recent have been the discoveries in bacteriology which have led
to vast improvements in our methods of treatment of wounds and the
performance of operations.

While the principles established by Lord Lister have remained
unchanged, the details in the treatment have been greatly simplified and
made more efficient. For the information of the general reader, let me state
a few facts. Bacteria are divided into two principal classes, in accordance
with their form. One, known as “cocci,” from the Greek word coccus
—“berry”—may be likened to billiard-balls. Some of these occur in
bunches, which have been likened to bunches of grapes, and hence are
called, again from a Greek term, “staphylococci.” Others are arranged in
chains, like beads, and are called “streptococci.” These last are very much
more virulent and dangerous than the staphylococci. Both of these produce
pus or matter, and they are the most widely diffused and most common
forms found in infected or suppurating wounds. One form is the cause of
erysipelas. A second form, known as “bacilli,” may be likened to a lead-
pencil. Among the various bacilli that have been discovered are those of
tuberculosis, glanders, tetanus or lockjaw, etc. I omit many others found in
medical disorders, as they do not concern this paper. How important these
discoveries are may be seen by the following facts: Tuberculosis, next to
that of suppuration, is, perhaps, the most widely extended infection to
which man, as well as animals, is liable. We are all familiar with it in the
form of “consumption,” but the non-medical reader is, perhaps, not aware
of the fact that it affects not only the lungs, but also the bowels in
consumption of the bowels; the bones, as is seen by every surgeon almost
daily, and especially as the cause of the crooked backs seen in spine
diseases; in the joints, as is seen in hip-joint disease, white swelling of the
knee, ankle-joint disease, and similar disease of all the other large joints of
the body; in the brain, in tubercular meningitis; in the abdominal cavity, in
tubercular peritonitis; in the skin, in certain forms of ulceration, commonly
called lupus; in the glands, as in the swollen glands, or “bunches,” in the
neck, and endless other varieties which I need not name.
The bacillus of lockjaw is found in great abundance around stables, and
this explains the fact that hostlers, drivers, cavalrymen, all of whom had to
do with horses, are especially liable to attacks of lockjaw. Moreover, certain
bacteria thrive best when exposed to the open air. Other bacteria, and
among them the bacilli of lockjaw, thrive best when the air is excluded, and
this explains the danger of treading on a rusty nail, which is popularly and
rightly known as peculiarly liable to produce lockjaw. The reason is not
because it is a nail, nor because it is old, nor because it is rusty, but because

from the earth in which it lies it is most apt to be the means of introducing
into a punctured wound the bacilli of lockjaw. Such a wound bleeds but
very little, the blood soon crusts and excludes the air, and if any of the
bacilli of lockjaw have been carried into the body, they find in such a closed
wound, from which the air is excluded, the most favorable conditions for
growth and infection of the whole body. Knowing these facts from
experiment, the treatment is clear. Lay open such a wound and disinfect it.
These two forms, the “cocci,” or berry-like bacteria, and the “bacilli,”
or rod-like bacteria, comprise the great majority of dangerous bacteria.
It must be remembered that there is an enormous number of bacteria
which are not dangerous; some of them are entirely harmless even if
introduced into the human body. Others are the bacteria of decomposition,
or putrefaction, which are known as “saprophytic” bacteria. All of the
harmless ones are known as “non-pathogenic,” that is, non-producers of
disease. Those which produce disease are known as “pathogenic,” and those
which produce suppuration as “pyogenic” or pus-producing bacteria.
All of these bacteria are plants, and not, as is very frequently supposed,
animals of a low form. The danger from their introduction into the body can
be best appreciated, perhaps, by the statement of Belfield, who estimated
that a single bacterium which weighs, approximately, only the 1-40,000,000
part of a grain, if given plenty of food and plenty of “elbow room,” would
so rapidly develop that in three days it would form a mass weighing 800
tons! It is the old story of the blacksmith who was to get a penny for the
first nail, two for the second, four for the third, and so on till a set of shoes
would cost more than Crœsus could pay for.
The effect of the bacteria has been determined by experiment to be
proportionate to the dose. A cubic centimetre is a cube two-fifths of an inch
on each side. One-tenth of such a cube of pure culture of one bacterium
(Proteus vulgaris) contains 225,000,000 bacteria, and if injected under the
skin of a rabbit will produce death. Less than 18,000,000 will produce no
effect whatever. Of one kind of staphylococcus, if 250,000,000 are
introduced under the skin of a rabbit there will be produced a small abscess,
but it requires 1,000,000,000 to produce speedy death. On the other hand, of
the bacillus of lockjaw it requires only 1000 to produce death, so virulent is
this germ.

Moreover, their effect on tissues and persons in different states varies
very much. Thus, it is found that when a certain number of bacteria are
injected into the cavity of the abdomen of an animal, if the animal is healthy
and the peritoneum (the thin lining membrane of the abdomen) is healthy,
the animal will recover perfectly well; but if the peritoneum be scraped and
torn (and it must be remembered that the healthy peritoneum is devoid of
sensation), that the same dose which before was harmless will now produce
a violent peritonitis and very likely death. The practical lesson from this
experiment upon animals is very evident. Every surgeon who opens the
abdomen is most careful, if possible, not to injure the peritoneum, but
manipulates with the greatest care lest fatal results follow any serious injury
to that membrane. So, too, if the general health be impaired, it is found that
an injection from which a healthy animal would recover will be followed by
fatal consequences if the general health is below par. Again, if an animal
has a simple fracture of his thigh-bone, and that is the only injury that he
receives, no infection from the exterior having occurred, he will make a
good recovery; but if at the same time he receives a lacerated wound, it may
be even in another part of the body, and this wound, not being cared for
most scrupulously, becomes infected, the infection will fasten on the distant
spot of least resistance, the broken thigh-bone, and will produce a most
dangerous and very frequently fatal form of inflammation.
I need scarcely point out in this connection, as in fact throughout this
entire consideration of bacteriology, how important a part in its
development has been played by experiment upon animals. The
experimental facts just stated are of vital importance in the treatment of
surgical diseases, and evidently could not have been determined upon
mankind. It is not too much to say that had vivisection been restricted or
prohibited the surgery of to-day would be the barbarous surgery of thirty
years ago.
Even granting that an enormous number of the bacteria are harmless,
the wonder is that with so many foes on every hand we live an ordinary
lifetime. Fortunately, however, in the human body there is not only a lack of
food sufficient and “elbow room” enough for them to work their dire
effects, but there is that which “makes for righteousness” in our physical
organization as well as in our souls.

The moment that bacteria are introduced into the human body a certain
number of cells hasten to destroy them. These are called “phagocytes” or
devouring cells, because they eat up the bacteria. Whether the patient
survives or dies depends on whether the bacteria get the upper hand of the
phagocytes or the phagocytes the upper hand of the bacteria.
These statements are very easy to make, but the results have only been
obtained by prolonged and laborious investigations in the laboratory and by
experiments upon animals which have demonstrated these facts.
The bacteria are recognized by various methods: First, by form. Many
which are identical in appearance, however, differ greatly in effects. A
handful of turnip-seed and a handful of rape-seed look very much alike, but
if they are planted the plants differ so greatly that we can recognize the
difference in the seed by the difference in the crop; hence the second
method of recognizing differences in bacteria is by planting them. Different
methods have been practised. Some are sown on the raw surface of a
potato; others on bread paste; others in certain jelly-like materials, such as
gelatine or agar-agar. It was soon found as a result of these experiments that
the bacteria flourished best, some in one soil, some in another. Again, the
crops of mould which come from them differ greatly in color, some being
black, some red, some white, some yellow, etc. A third method also is by
staining them with various dyes, when it is found that some bacteria will
take one stain best, others will take another, and so on through the whole
list.
At first it was thought that these bacteria existed chiefly in the air, and
hence in Lister’s early methods powerful spray-producing apparatus were
used; but while it is true that they do exist in the air, it is found that this is
not the principal source of infection. There is no substance (which has not
been disinfected) that is not covered with the germs of these little plants.
They exist in our food and drink; but the intestine is, one may say, a natural
home in which many exist without harm to the body. For surgical purposes
their existence is most important, first, in the earth, where, as I have already
shown, the bacillus of lockjaw is most frequently found. So, too, the
bacillus of wool-sorters’ disease (Anthrax) exists in the earth. If an animal
dying of anthrax is buried, worms coming from the carcass up through the
ground carry the infection, so that other animals grazing over this surface
will become readily infected. The means by which we can avoid infection

from the earth is very evident, viz., every person who has been run over by
the cars or who has fallen on the ground and broken his leg, etc., must have
the wound most carefully cleansed from all dirt. If this is scrupulously done
the danger of tetanus or other similar earth-born bacterial disease is almost
nothing.
A still greater danger to every patient, however, is found in the
clothing, in the skin, and all dressings which are applied to wounds. The
skin is full of bacteria of the most dangerous kind; even the spotless hands
of the bride, in the eyes of the surgeon, are dirty. No one can touch a wound
with ordinarily clean hands without infecting it. All clothing, dressings—
e.g., lint and soft linen rags, and such like—are full of bacteria of the most
dangerous kind. Perhaps the most dangerous place is the space under the
nails of the surgeon’s hand, for the mere mechanical removal of any dirt
under the nails by cleansing them does not make them clean surgically. The
nails must be cut short and prepared in a way I shall mention directly, or
they are full of peril to any patient into whose wound a non-disinfected
finger is introduced. Again, another source of infection which thirty years
ago we never thought of is our instruments. Then instruments were washed
with soap and water and were made clean to the eye, but they were still
covered with invisible death-dealing bacteria which hid especially in the
joints and irregularities of the surface of all instruments.
All of these somewhat detailed statements lead up to a consideration of
the difference between the old surgery and the new. Thirty years ago when
an operation was to be performed or an accident cared for we laid out our
instruments which were visibly clean, used them with hands which were as
clean as those of any gentleman, and applied soft linen rags, lint, and other
dressings. To-day we know that these apparently clean instruments, hands,
and dressings are covered with bacteria, which produce infection, and,
therefore, suppuration, and frequently run riot in blood-poisoning,
erysipelas, lockjaw, and death.
How does a modern surgeon perform an operation? All bacteria can be
killed by heat. Cold has no effect upon them, but the temperature of boiling
water (212° Fahr.) is sufficient to destroy them all usually within fifteen or
twenty minutes; hence, first, instruments are all boiled; and, secondly,
dressings are either steeped in such solutions as have been found to destroy
the bacteria, such as carbolic acid or corrosive sublimate, or other

preparations, or, still better, are placed in sterilizers, that is to say, metal
cylinders, which are then filled with steam, usually under pressure, so as to
obtain a temperature of 240° Fahr., and thus make sure of the death of the
bacteria. Unfortunately, our hands cannot be boiled or steamed, but the
modern surgeon first uses soap and water most vigorously over his hands
and arms up to the elbow. The nails are cut short and the scrubbing-brush is
especially applied to the nails so as to clean the fingers at the ends. Then by
various means, such as pure alcohol, which is one of our best disinfectants,
or solutions of corrosive sublimate, and other means too technical to
mention, the hands are sterilized. Rubber gloves are frequently used, so as
to preclude infection, as they can be steamed to 240° Fahr. Removing at
least his outer clothing, the surgeon puts on a cotton gown which has been
steamed and so made free from bacteria. Not a few surgeons also wear
sterilized caps, so that any bacteria in the hair will not be sifted into a
wound, and some wear respirators of sterile gauze over the mouth and beard
for the same reason. All the dressings have been sterilized by superheated
steam. All the threads by which blood-vessels are tied have been either
boiled or otherwise sterilized. All the material for sewing up the wounds,
and the needles with which they are sewn, have been similarly disinfected.
The skin of the patient is also sterilized, usually the day beforehand, in the
same manner in which the surgeon’s hands have been disinfected, and are
disinfected a second time just at the moment of the operation. If the case is
one of accident, such as a crushed leg from a trolley-car, all of the dirt is
most carefully washed away with soap and water, and the parts are
disinfected, not only on the exterior, but also by prolonged washing with
some cleansing agent in the interior of the wound, the patient being under
the influence of ether, of course.
It is easily seen from such a description of a modern operation that no
case can receive due care in one of our modern homes, even the best. The
facilities do not exist, and hence surgeons are more and more declining to
do operations, whether for accident or disease, in private houses, except in a
case of absolute necessity, and a happy custom is growing more and more
in favor with the community of having all operations and all accidents cared
for in a well-equipped hospital.

RESULTS OF MODERN SURGERY

As the result of our ability to perform operations without pain, thanks
to anæsthesia, and our ability to perform operations without infection, and,
therefore, almost without danger, thanks to antisepsis, the range of modern
surgery has been enormously increased. Unless one has lived through the
old surgery and into the new he scarcely can appreciate this widening of the
field of operative surgery. Thirty years ago, in consequence of the great
danger of opening the head, the chest, or the abdomen, or, in fact, of making
an incision anywhere about the body, the surgeon never dared to interfere
until he was obliged to do so. Hence, not only were many modern
operations not even thought of, but in obscure cases we had to wait until
time and disease developed symptoms and physical signs such that we were
sure of our diagnosis, and then, knowing that death would follow if we did
not interfere, we ventured to operate. Now we anticipate such a fatal
termination, and in most cases can avert it. In perhaps no class of cases has
the benefit of this immunity from infection and danger been shown than in
the obscure diseases of the brain and the abdomen. To-day, if we are
uncertain as to whether there is serious danger going on which, if
unchecked, will result in death, we deliberately open the one cavity or the
other, in order to find out the exact state of affairs. Supposing that the
mischief is trifling, or even that there is no mischief, we then know how to
deal with the symptoms which have been puzzling us. So far as the
exploratory operation is concerned, the patient recovers from it in a short
time, and, meantime, perhaps has also been cured of the symptoms which
were before so ill understood. If any serious disease is found, in the
majority of cases we can cope with it successfully. Before the days of
antisepsis and anæsthesia the field of operation was greatly restricted, and
practically the removal of tumors, amputations, and a few other operations
were all that were done. Now all the then inaccessible organs are attacked
with an intrepidity born of an assurance of safety. Recovery usually sets the
seal of approval on the judgment of the surgeon. Thirty years ago, taking all
operations together, fully one-third of our patients died, many of them often
from slight operations which were followed by infection. To-day, including
even the far more grave operations which are now done, the general
mortality will scarcely exceed five per cent., and many surgeons are able, in

a series of several hundred operations, to save ninety-seven out of every
hundred patients!

SERUM TREATMENT

Another remarkable recent discovery, the result of numerous and
careful investigations in the laboratory, is a wholly new means of treatment,
viz., that method which is known as orrhotherapy, or serumtherapy, or the
treatment by injecting certain antitoxins under the skin by a hypodermatic
syringe. It would lead me too far to enter into the theory upon which these
were first used. Suffice it to say that in the blood of an animal that has
passed through a certain disorder the liquid part of the blood contains an
antidote or antitoxin. If a certain amount of this is injected under the skin of
an animal or man suffering from the same disorder in its incipient stages,
the antitoxin prevents the development of the disease. The use of this
method has thus far been much more medical than surgical, and its results
in diphtheria and other medical disorders have been perfectly marvellous. In
surgery, however, less favorable results have been obtained, but in all
probability in the future we shall be able to do for some of our surgical
disorders what the physician can do to-day for diphtheria. [For the results in
diphtheria, see Professor Osler’s paper.]
There has also been discovered another means which in surgery has
rendered some valuable service. From certain organs, as, for instance, the
thyroid gland (the gland whose enlargement produces goitre), we can obtain
a very potent extract of great value. In cases of goitre very noteworthy
results have already been obtained by the administration of the thyroid
extract. A number of other organs in the body of animals have been used to
combat certain disorders in the human body with advantage. The chief
development of both of these new forms of medication, however, will take
place in the twentieth century.

INSTRUMENTS OF PRECISION

Another direction in which the century has seen enormous progress is
in the introduction of instruments of precision. When I was a student in the
early 60’s, instruction in microscopy was conspicuous only by its absence
from our medical curriculum. Now every student who graduates is more or
less of an accomplished microscopist, and carries into his practice the
methods and observations which the microscope furnishes. At the same
period I remember being greatly interested in a discussion which two of my
teachers had as to whether it was possible to make an application accurately
to the vocal chords in the larynx. Now every tyro in medicine makes such
applications to the larynx as a routine procedure in cases requiring it, and
similar methods have been applied by the ophthalmoscope to examine the
interior of the eye; the rhinoscope, to examine the interior of the nose; the
otoscope, for examination of the ear; and other similar instruments for
examining all the other hollow organs in the body. If I add to these the
hypodermatic syringe; the aspirator, which may be described as a large
hypodermatic syringe for suction instead of injection; the clinical
thermometer, which was introduced in the late 60’s; the hemostatic forceps,
for controlling hemorrhage by seizing the blood-vessels and clamping them
till we have time to tie them; and other instruments intended to facilitate our
operative methods, it will be seen at once that the armamentarium of the
modern surgeon is very different from that of his predecessor at the
beginning, or even at the middle, of the century.

THE RÖNTGEN RAY

One of those extraordinary discoveries which startle the whole world
came nearly at the end of the nineteenth century, in the winter of 1895–96.
At that time a modest professor in the University of Würzburg announced
that he could readily see the skeleton inside the body through the flesh!
Naturally, the first announcement was received with almost absolute
incredulity; but very soon his discovery was confirmed from all sides, and it
has now taken its place among the recognized phenomena of science. By
means of certain rays, which, being of unknown nature, were called “X”-
rays, after the well-known mathematical X, or unknown quantity, Professor
Röntgen has shown us that not only can the bones be seen, but that almost

every substance in the body can be seen and reproduced in pictures. The
reason for this is because they are all obstacles to the passage of these X-
rays and so produce shadows on a sensitized photographic plate. If the
exposure is sufficiently prolonged the rays penetrate even through the bones
and act upon the photographic plate, so that no shadow remains. If the rays
are allowed to penetrate for a shorter time the bones show dense shadows,
and one can get a light shadow of the soft parts. If the exposure is still
shorter, then we can recognize the dense shadow of the bone, the much less
dense shadows of the muscles, and the still lighter shadows of the layer of
fat immediately under the skin. The heart can be seen beating, and its
shadow is now a well-recognized feature in skiagraphs of the chest. At first
it was thought impossible to discover anything inside the bony skull, but
there are now on record nearly a score of instances in which bullets have
been detected within the skull, and after trephining have been found and
removed exactly at the location indicated. It is a very common thing now to
locate a piece of steel or other similar foreign bodies within the eyeball by
the method of Dr. Sweet, or some similar method, within one or two
millimetres (a millimetre is one-twenty-fifth of an inch). It is now well
recognized that even stones in the kidney will throw shadows sufficiently
strong for them to be recognized, and by noting their level in relation to the
vertebræ we can tell precisely in what part of the kidney to make the
incision in order to find and remove them. It has happened to myself and
many other surgeons in the past to cut down upon a kidney, believing that
there was a stone in the kidney, only to find that we had been misled by the
apparently clear symptoms of such a foreign body. In future no such
mistake should be made by any surgeon within reach of a skilful
skiagrapher. Unfortunately, gall stones and numerous other foreign bodies,
vegetable substances such as beans, corn, wood, etc., being as transparent to
the X-rays as are the soft parts, are not revealed by means of this new
method of investigation; but cavities in the lung, abscesses in bone, and
similar diseases which produce thinning of the lung, bone, and other such
organs, and so lighten instead of deepen the shadows, can now be
recognized by means of light spots in the pictures as well as others by
means of a shadow.
I spoke a moment ago of the need of a “skilful” skiagrapher, for it must
be remembered that there may be the same difference in the personal skill,
and, therefore, in the reliability of the results in skiagraphy as there is in

photography. A poor photographer will get very different results from a
skilful one, even if he uses precisely the same quality of plates and
precisely the same camera. Personal skill and experience in the skiagrapher
is, therefore, one of the most important elements in success. It must be
remembered also that the X-rays in not a few cases may mislead us. I have,
personally, fractured a bone on account of deformity, taken an X-ray picture
immediately after the operation, the picture showing not the slightest
evidence of a fracture, which I absolutely knew existed. Moreover, foreign
bodies found on the outside of the person may mislead us, as, for example,
the metal part of suspenders, a coin in one’s pocket, and such like. They
look in the picture as if they were inside rather than outside the body, and
any article the shape or size of which would not reveal its nature might
easily be mistaken for a foreign body within the patient. Therefore, in many
cases only an expert can determine precisely what the skiagraph means. I
especially mention this, because there is a tendency at present to utilize
skiagraphs in court in order to convince the jury that such a picture is an
evidence of malpractice. Such pictures always need an interpreter in order
to judge correctly of their meaning. It is precisely as if the jury were asked
to look through a microscope. I have been myself accustomed to use the
microscope for thirty years, but there are many instances even yet in which
I am obliged to ask a pathologist or bacteriologist what I really am looking
at in the microscope. While one may make a mistake of small moment in
some cases, yet if a man’s life or liberty or purse is at the mercy of a jury
which does not know how to interpret a skiagraph, and, may, therefore, give
a verdict which is “precisely wrong,” as Professor Lincoln, my old teacher
of Latin, used to call many of our translations, it will be a very serious
matter and lead to gross injustice.

CITY AND VILLAGE HOSPITALS

Another great improvement in our means of caring for our surgical
patients is the establishment of hospitals all over the land. These, happily,
are not limited to our great cities, but in every country town and not a few
large villages small but well-equipped and well-managed hospitals have
been established which have done incalculable good. It is not too much to

say that every city or town establishing such a hospital is repaid a
hundredfold.

TRAINED NURSES

The trained nurse has fortunately come to stay. In fact, our antiseptic
methods as above described have made the trained nurse indispensable. The
old nurse, who, by many clumsy experiments on her patients, had obtained
a certain rule-of-thumb knowledge of the care of the sick, can no longer
assist in a surgical operation or properly care for any surgical patient. The
modern nurse must of necessity be a well-educated, well-trained woman,
knowing thoroughly modern antiseptic methods, and on the alert to observe
every symptom of improvement and every signal of danger.
Without a well-trained nurse it is impossible at the present day properly
to care for any serious surgical case, and I gladly bear witness to the
intelligence, fidelity, and skill of scores of nurses who have assisted me, and
without whom I should have felt as one blade of a scissors without its
fellow.

SPECIAL OPERATIONS

Amputations and Compound Fractures.—Having now traced the
different modes of thought which have aided surgical progress in the
nineteenth century and the improved means of investigation, let us turn
finally to the progress in individual operations. As to amputations and
compound fractures, I have already indicated the immense improvements
which have followed the introduction of anæsthesia, and especially of
antisepsis, which have brought the mortality of amputations down from
fifty or sixty per cent. to ten or fifteen per cent., and in compound fractures,
once so dreaded, since the mortality was not infrequently as high as two out
of three, to a relatively insignificant danger.
Tumors.—In no department, perhaps, has the introduction of antisepsis,
and the use of catgut and silk ligatures after the antiseptic method, brought

about a greater improvement than in operations for tumors. The startling
reluctance of Sir Astley Cooper to operate on King George IV. for so simple
and small a tumor as a wen, lest erysipelas might follow and even destroy
his life, is in marked contrast with the success and therefore the boldness of
modern surgeons. Tumors in all parts of the body, whether they be external
or internal, whether they involve the wall of the chest or are inside the
abdomen, are now removed with almost perfect safety. Anæsthesia has
made it possible to dissect out tumors in so dangerous a region as the neck,
where the surgeon is confronted with adhesions to the jugular vein, the
carotid artery, and the nerves of the neck and of the arm, with the greatest
impunity. Such an operation not uncommonly lasts from three-quarters of
an hour to an hour and a half, and involves often the removal of two or
three inches of the jugular vein and many of the large nerves, the removal
of which a few years ago would have been deemed an impossibility.
Goitre.—One of the most striking instances of progress is operations on
goitre. Writing in 1876, the late Professor Samuel D. Gross noted it as
something remarkable that Dr. Green, of Portland, Maine, had removed
seven goitres with two deaths, and the late Dr. Maury, of Philadelphia, had
extirpated two goitres with one death. In marked contrast to this Professor
Kocher, of Berne, in 1895, reported one thousand cases, of which eight
hundred and seventy were non-cancerous, and he lost of these last but
eleven cases, or a little over one per cent. In 1898 he reported six hundred
additional cases, with only one death in the five hundred and fifty-six non-
cancerous cases, or a mortality of only 0.1 per cent. It will be seen,
therefore, that an operation which a few years ago was excessively fatal has
become almost, one might say, a perfectly safe operation.
Surgery of the Bones.—Operations on bones, apart from amputations,
show also a similar improvement. In cases of deformity following fracture
we now do not hesitate to cut down upon the bone and refracture it or
remove the deformed portion, join the ends together, dress the part in
plaster of Paris to secure fixation, and have the patient recover with little or
no fever and no suppuration. Above the elbow a large nerve runs in a
furrow in the arm bone, and in case of fracture this is liable to be torn and a
portion of it destroyed. The result of it is paralysis of all the muscles on the
back of the forearm from the elbow down and consequent inability to
extend either wrist or fingers, making the hand almost useless. In a number

of cases the nerve has been sought for and found, but the ends have been
too far apart for successful union and sewing them together. In such cases
we do not hesitate now, in order to bring the two ends of the nerve together,
to remove one or two inches of the arm bone, wire the shortened bone, sew
the now approximated ends of the nerve together, put the arm in plaster, and
as soon as the wound is healed, with appropriate later treatment to the
muscles we can obtain in a reasonable number of cases a perfect, or almost
perfect, union of the nerves with a re-establishment of the usefulness of the
hand.
In very many cases the bones are deformed as a result of rickets, and in
some cases in consequence of hip-joint disease. In such cases the leg is
crooked or flexed, and cannot be used for walking. Such cases of stiff joints
and crooked legs are now operated on, one might say, wholesale. At the
International Medical Congress, held in Copenhagen in 1884, Professor
Macewen, of Glasgow, reported 1800 operations on 1267 limbs in 704
patients, in which he had sawn or chiselled through the bones so as to
fracture them, placed them in a straight position, and after a few weeks the
bone has become consolidated and the leg or arm made straight. Every one
of these operations was successful, excepting five cases, and even these
deaths were not due to the operation, but to some other disorder, such as an
unexpected attack of pneumonia, diphtheria, or scarlet fever.
Surgery of the Head and Brain.—In the surgery of the head we find one
of the most remarkable illustrations of the modern progress of surgery.
Fractures of the skull have been the most dangerous and fatal of accidents
until within a short time. Of course, many of them must necessarily, even
now, be fatal, from the widespread injury to the bones and the brain. But
our modern methods, by which we can disinfect the cavities of the ear, the
nose, and the mouth, with which these fractures often communicate, and
through these avenues become infected, are so successful that such cases,
instead of being looked upon as hopeless, are in a majority of instances
followed by recovery. Even gun-shot wounds, in which the ball may remain
inside the cavity of the head, are successfully dealt with, unless the injury
produced by the ball has been necessarily fatal from the start. Fluhrer, of
New York, has reported a very remarkable case of gun-shot wound, in
which the ball entered at the forehead, traversed the entire brain, was
deflected at the back of the skull, and then pursued its course farther

downward in the brain. By trephining the skull at the back he found the
ball, passed a rubber drainage tube through the entire brain from front to
back, and had the satisfaction of seeing the patient recover.
Until 1884 it was excessively difficult to locate with any degree of
accuracy a tumor within the brain, but in that year Dr. Bennett, of London,
for the first time accurately located a tumor within the skull without there
being the slightest evidence on the exterior of its existence, much less of its
location. Mr. Godlee (surgeons in England are not called “Dr.,” but “Mr.”)
trephined the skull at the point indicated, found the tumor, and removed it.
True, this patient died, but the possibility of accurately locating a tumor of
the brain, reaching it and removing it, was now demonstrated, which is far
more important to humanity at large than whether this individual patient
survived or not. Since then there have been a very large number of tumors
successfully removed. The latest statistics are those of Von Bergmann, of
Berlin, in 1898. He collected 273 operations for brain tumors, of which 169
(61.9 per cent.) recovered, and 104 (38.1 per cent.) died. This is by far the
best percentage of results so far reported, but there is reason to believe that
with the constant improvement in our ability to locate such tumors and in
our methods of removing them, the mortality rate will be still further
lessened.
Even more successful than the surgery of brain tumors has been the
surgery of abscess of the brain. I have no available statistics of the exact
numbers, but it is certain that several hundred have been operated on, and
with even better success than in the case of brain tumors. The most frequent
cause for such abscesses is old and neglected disease of the ear. No child
suffering from a “running from the ear,” which is especially apt to follow
scarlet fever and other similar disorders, should be allowed to pass from
under the most skilled treatment until a cure is effected. This is the
commonest cause of abscess of the brain. The inflammation in the ear,
which begins in the soft lining of the cavities of the ear, finally extends to
the bone, and after years of intermittent discharge, will suddenly develop an
abscess of the brain, which, if not relieved, will certainly be fatal. Prompt
surgical interference alone can save life, and, happily, though we cannot
promise recovery in all, a very large percentage of success is assured.
In epilepsy, as a result of injuries of the head, in a moderate number of
cases, we can obtain a cure of the disease by operation, but in the great

majority of cases, and, one may say, practically in all of the cases in which
the epilepsy originates “of itself,” that is to say, without any known cause, it
is useless to operate, certainly at least after the epileptic habit has been
formed. Possibly were operation done at the very beginning we might
obtain better results than experience thus far has shown us is possible.
Very many cases of idiocy are constantly brought to surgeons in the
hope that something can be done for these lamentable children.
Unfortunately, at present surgery holds out but little hope in such cases. In a
few exceptional instances it may be best to operate, but a prudent surgeon
will decline to do any operation in the vast majority of cases.
Surgery of the Chest and Heart.—The chest is the region of the body
which has shown the least progress of all, and yet even here the progress is
very marked. When, as a result of pleurisy, fluid accumulates on one side of
the chest, even displacing the heart, we now do not hesitate to remove an
inch or two of one or more ribs and thoroughly drain the cavity, with not
only a reasonable, but in a majority of cases, one may almost say, a certain,
prospect of cure. We have also entered upon the road which will lead us in
time to a secure surgery of the lung itself. A few cases of abscess, of serious
gun-shot wound, attended by otherwise fatal hemorrhage, and even of
tubercular cavities in the lungs have been successfully dealt with, but the
twentieth century will see, I have no doubt, brilliant results in thoracic
surgery.
One of the most striking injuries of the chest has recently assumed a
new importance, viz., wounds of the heart itself. In several instances an
opening has been made in the bony and muscular walls of the chest, and a
wound of the heart itself has been sewed up. The number is as yet small, but
there have been several recoveries, which lead us to believe that here, too,
the limits of surgery have by no means been reached.
Surgery of the Abdomen.—Of the abdomen and the pelvis a very
different story can be told. These cavities might almost be called the
playground of the surgeon, and the remarkable results which have been
obtained warrant us in believing that even greater results are in store for us
in the future.
In the earlier part of this article I spoke of the advantages of the study
of the pathological anatomy or the diseased condition of individual organs.

Perhaps no better illustration of the value of this can be given than in the
studies of appendicitis. This operation has been one of the contributions to
the surgery of the world in which America has been foremost. While there
were one or two earlier papers, Willard Parker, of New York, in 1867, first
made the profession listen to him when he urged that abscesses appearing
above the right groin should be operated on and the patient’s life saved. But
it was not until Fitz, of Boston, in 1888, published his paper, in which he
pointed out, as a result of a study of a series of post-mortem examinations
of persons dying from such an abscess above the right groin, that the
appendix was the seat of the trouble, that this so frequent disease was
rightly understood and rightly treated.
As a result of the facts gathered in his paper, the treatment was
perfectly clear, not only that we ought to operate in cases of abscess, but
that in the case of patients suffering from two or more attacks, and often
from even one attack of appendicitis, the appendix should be removed to
prevent such abscess.
The mortality in cases in which such an abscess has formed is, perhaps,
quite twenty or twenty-five per cent., whereas, if patients are operated on
“in the interval,” that is to say, between attacks, when the abdominal cavity
is free from pus, the mortality is scarcely more than two or three per cent.,
and may be even less than that.
Surgeons are often asked whether appendicitis is not a fad, and whether
our grandfathers ever had appendicitis, etc. As a matter of fact, in my early
professional days, appendicitis was well known. It was called “localized
peritonitis” or localized “abscess,” but while the disease was very frequent,
its relation to the appendix was not recognized until from his study of its
pathology an American pointed it out. Even now European surgeons, with a
few exceptions, are not alive to the need for operation in such cases.
There is little doubt that the great prevalence of grippe during the last
few years has increased the number of cases of appendicitis, both of them
being catarrhal conditions of the lining membrane of the same continuous
tract of the lungs, the mouth, the stomach, and the intestines.
One of the most fatal accidents that can befall a patient is to have an
ulcer of the stomach perforate so that the contents of the stomach escape
into the general abdominal cavity. Until 1885 no one ventured to operate in

such a case. In an inaugural dissertation by Tinker, of Philadelphia, two
hundred and thirty-two cases of such perforating ulcers of the stomach were
reported, of which one hundred and twenty-three recovered, a mortality of
48.81 per cent. In not a few of them, if prompt instead of late surgical help
had been invoked, a very different result would have been reported. If no
operation had been done, the mortality would have been one hundred per
cent.
In cancer of the stomach itself we are able, as a rule, to make a positive
diagnosis only when a perceptible tumor is found. By that time so many
adhesions have formed, and the infection has involved the neighboring
glands to such an extent, that it is impossible to remove the tumor, but the
statistics even here are not without encouragement, at least for comfort if
not for life. In many cases the tumor has been removed and the stomach and
intestine joined together by various devices, and the mortality, which is
necessarily great, has been reduced by Czerny to twelve per cent. and by
Carle to seven per cent. Even the entire stomach has been removed in
several cases, and recovery has followed in about one-half. Most of these
patients, however, have died from a return of the disease.
When, as a result of swallowing caustic lye or other similar substances,
the gullet (the œsophagus) becomes contracted to such an extent that no
food can be swallowed, we now establish an opening into the stomach
through which a tube is inserted at meal-time, and the patient has his
breakfast, dinner, and supper poured into his stomach through the tube. If
the stricture of the œsophagus is from malignant disease, of course this only
prolongs life by preventing a horrible death by starvation, but in cases in
which it is non-malignant life is indefinitely prolonged. The mortality of
such an operation is very small.
By a freak of nature or by disease the stomach sometimes is narrowed
in the middle, forming what is called an “hour-glass stomach.” In such a
case we open the abdomen, make an opening into the two parts of the
stomach and unite the two so that we re-establish the single cavity of the
stomach. The mortality of the operation is very slight, eight per cent. Again,
sometimes the stomach becomes unduly dilated, thus interfering seriously
with its function. A number of surgeons in such cases have simply folded
over the wall of the stomach upon itself and have sewed the two layers

together, taking a plait or “tuck” in the stomach wall, and have restored it to
its normal capacity and function.
One of the most important advances has been made in the treatment of
gall stones. The bile in the gall bladder is in a state of quiescence, which is
favorable to a deposit of crystals from the bile. These crystals become
agglutinated together into larger or smaller solid masses called gall stones.
Sometimes the number of these is very small, from one to four or five;
sometimes they accumulate in enormous numbers, several hundreds having
been reported in a number of instances. When they are small they can
escape through the duct of the gall bladder into the bowel and create no
disturbance, but when they are large, so that they cannot make their escape,
they not uncommonly are causes not only of serious discomfort and
prolonged ill-health, but often prove fatal. Nowadays one of the safest
operations of surgery is to open the abdomen and the gall bladder and
remove this menace to life, and the great majority of such patients recover
without any untoward symptoms. Even large abscesses of the liver, and,
what is still more extraordinary, large tumors of the liver, are now removed
successfully. A year ago all of the reported cases of tumor of the liver were
collected which had been operated from 1888 to 1898, seventy-six in all.
The termination in two cases was unknown, but of the other seventy-four,
sixty-three recovered and eleven died, a mortality of only 14.9 per cent.
The surgery of the intestines by itself is a subject which could well
occupy the entire space allowed to this article. I can only, in a very
superficial way, outline what has been done. Hernia or rupture is a
condition in which through an opening in the abdominal wall a loop of the
bowel escapes. If it can be replaced and kept within the abdomen by a
suitable truss this was the best we could do till within the last ten or fifteen
years. The safety and the painlessness of modern surgery which have
resulted from the introduction of anæsthesia and antisepsis are such that
now no person suffering from such a hernia, unless for some special
personal reason, should be allowed to rely upon a truss, which is always a
more or less treacherous means of retaining the hernia. We operate on all
such cases now with impunity. Coley has recently reported a series of six
hundred and thirty-nine cases, all of which recovered with the exception of
one patient. Even in children, if a truss worn for a reasonable time, a year or

so, does not cure the rupture, operation affords an admirable prospect of
cure.
Every now and then a band forms inside the abdomen, stretching like a
string across the cavity. If a loop of bowel slips under such a band, it can be
easily understood that total arrest of the intestinal contents ensues, a
condition incompatible with life. There are other causes for such “intestinal
obstruction,” which are too technical to be described in detail, but this may
be taken as a type of all. It is impossible, of course, to tell before opening
the abdomen precisely the cause of the obstruction, but the fact is quickly
determined in most cases. If we open the abdomen promptly, we can cut
such a band or remove the other causes of obstruction in the majority of
cases, and if the operation has not been too long delayed, the prospect of
entire recovery is good. The mortality which has followed such operations
has been considerable, and by that I mean, say, over twenty per cent., but a
very large number of the fatal cases have been lost because the operation
has been delayed. In fact, it may be stated very positively that the mere
opening of the abdomen to find out precisely the nature of any disease or
injury is attended with but little danger. If further surgical interference is
required, the danger will be increased proportionately to the extent and
gravity of such interference. But “exploratory operations,” as we call them,
are now undertaken constantly with almost uniform success.
Even in cancer of the bowel, we can prolong life, if we cannot save it.
Cancer of the bowel sooner or later produces “obstruction” and so destroys
life, but in such cases we can either make a permanent opening in the bowel
above the cancer, and so relieve the constant pain and distress which is
caused by the obstruction, or, in a great many cases, we make an opening in
the bowel above the cancer, and another below it, and, by uniting the two
openings, if I may so express it, “side-track” the contents of the bowel. If
the cancer has no adhesions and the patient’s condition allows of it, we can
cut out the entire portion of the bowel containing the cancer, unite the two
ends, and thus re-establish the continuity of the intestinal canal. As much as
eight feet, nearly one-third of the entire length of the bowel, have been
removed by Shepherd, of Montreal, and yet the patient recovered and lived
a healthy life.
Similarly in gun-shot wounds, stab wounds, etc., involving the
intestine, the modern surgeon does not simply stand by with folded hands

and give opium and morphine to make the patient’s last few hours or days
relatively comfortable, but he opens the abdomen, finds the various
perforations, closes them, and recovery has followed even in cases in which
as many as seventeen wounds of the intestine have been produced by a gun-
shot wound.
The kidney, until thirty years ago, was deemed almost beyond our
reach, but now entire volumes have been written on the surgery of the
kidney, and it is, one might say, a frequent occurrence to see the kidney
exposed, sewed fast if it is loose, opened to remove a stone in its interior,
drained if there be an abscess, or, if it be hopelessly diseased, it is removed
in its entirety. The other kidney, if not diseased, becomes equal to the work
of both.
Of the pelvic organs, it would not be becoming to speak in detail, but
one operation I can scarcely omit: namely, ovariotomy. One of my old
teachers was Washington L. Atlee, who, with his brother, was among the
first ovariotomists in this country who placed the operation on a firm
foundation. I heard a very distinguished physician in 1862, in a lecture to
his medical class, denounce such men as “murderers”; but to-day how
differently does the entire profession look upon the operation! Instead of
condemning the surgeon because he did remove such a tumor, the
profession would condemn him because he did not remove it. The operation
had its rise in America. Ephraim McDowell, of Kentucky, in 1809, first did
the operation which now reflects so much credit upon modern surgery. The
mortality of the Atlees was about one in three. Now, owing to the immense
improvement introduced by the antiseptic methods, the deaths, in competent
hands, are not over five per cent., or even three per cent.
The limits of this article compel me to stop with the story very
imperfectly told, but yet, perhaps, it has been sufficient in detail to show
somewhat of the astonishing progress of surgery within the century, but
especially within the last quarter of the century.
About two decades ago one of the foremost surgeons of London, Mr.
Erichsen, said, in a public address, that “surgery had reached its limits.”
How short was his vision is shown by the fact that surgery at that time was
just at the beginning of its most brilliant modern chapter.

We have reached, in many respects, apparently, the limits of our
success, but just as anæsthesia and antisepsis and the Röntgen rays have
opened new fields wholly unsuspected until they were proclaimed, so I
have no doubt that the twentieth century will see means and methods
devised which will put to shame the surgery of to-day as much as the
surgery of to-day puts to shame that of thirty years ago, and still more of a
century ago. The methods by which this will be attained will be by the more
thorough and systematic study of disease and injury, so as to better our
means of diagnosis, and so prepare us for immediate surgical interference,
instead of delaying it, as we now do in many cases, for want of certain
knowledge; by the use of new chemical and pharmaceutical means to
perfect our antisepsis and possibly to introduce other methods of treatment;
but, above all, we shall obtain progress by the exact experimental methods
of the laboratory. We can never make progress except by trying new
methods. New methods must be tried either on man or on animals, and as
the former is not allowable, the only way remaining to us is to test all new
methods, drugs, and applications first upon animals. He who restricts, and,
still more, he who would abolish our present experiments upon animals, is,
in my opinion, the worst foe to the human race, and to animals, as well, for
they, as well as human beings, obtain the benefit derived from the method.
He may prate of his humanity, but he is the most cruel man alive.

W. W. Keen.

ELECTRICITY

T hedepartments
great importance which electricity has attained in many
of human activity is so constantly evident that we have
difficulty in realizing how short is the time which has been occupied in its
development. The latter half of the nineteenth century must ever remain
memorable, not only for the great advances in nearly all the useful arts, but
for the peculiarly rapid electric progress, and the profound effect which it
has had upon the lives and business of the people. In the preceding century
we find no evidences of the application of electricity to any useful purpose.
Few of the more important principles of the science were then known.
Franklin’s invention of the lightning-rod was not intended to utilize electric
force, but to guard life and property from the perils of the thunder-storm.
The numerous instructive experiments in frictional electricity, the first-
known form of electric manifestation except lightning, made clear certain
principles, such as conduction and insulation, and served to distinguish the
two opposite electric conditions known as positive and negative. Franklin’s
kite experiment confirmed the long-suspected identity of lightning and
electric sparks. It was not, however, until the discovery by Alexander Volta,
in 1799, of his pile, or battery, that electricity could take its place as an
agent of practical value. Volta, when he made this great discovery, was
following the work of Galvani, begun in 1786. But Galvani in his
experiments mistook the effect for the cause, and so missed making the
unique demonstration that two different metals immersed in a solution
could set up an electric current. Volta, a professor in the University of Pavia
and a foreign member of the Royal Society of England, communicated his
discovery to the president of the society in March, 1800, and brought to the
notice of the world the first means for obtaining a steady flow of electricity.
Before this event electric energy had been known to the experimenter in
pretty effects of attraction and repulsion of light objects, in fitful flashes of

insignificant power, or, as it appeared in nature, in the fearful bursts of
energy during a thunders-torm, uncontrolled and erratic. The analogous and
closely related phenomena of magnetism had already found an important
application in the navigator’s compass.

The simplest facts of electro-magnetism, upon which much of the later
electrical developments depend, remained entirely unknown until near the
close of the first quarter of the nineteenth century. Magnetism itself, as
exemplified in loadstone or in magnetized iron or steel, had long before
been consistently studied by Dr. Gilbert, of Colchester, England, and in
1600 his great work, De Magnete, was published. It is a first example, and
an excellent one, too, of the application of the inductive method, so fruitful
in after-years. The restraints which a superstitious age had imposed upon
nature study were gradually removed, and at the beginning of the century
just past occasional decided encouragement began to be given to physical
research. It was this condition which put into the hands of Humphry Davy,
of the Royal Institution, in London, at the opening of the century, a voltaic
battery of some 250 pairs of plates. With this a remarkably fruitful era of
electric discovery began. In 1802 Davy first showed the electric arc or
“arch” on a small scale between pieces of carbon. He also laid the
foundation for future electro-chemical work by decomposing by the battery
current potash and soda, and thus isolating the alkali metals, potassium and
sodium, for the first time. This was in 1807, and the result was not only to
greatly advance the youthful science of chemistry, but to attract the
attention of the world to a new power in the hands of the scientific worker,
electric current. A fund was soon subscribed by “a few zealous cultivators
and patrons of science,” interested in the discovery of Davy, and he had at
his service in 1801 no less than 2000 cells of voltaic battery. With the
intense currents obtained from it he again demonstrated the wonderful and
brilliant phenomenon of the electric arc, by first closing the circuit of the
battery through terminals of hardwood charcoal and then separating them
for a short distance. A magnificent arch of flame was maintained between
the separated ends, and the light from the charcoal pieces was of dazzling
splendor. Thus was born into the world the electric arc light, of which there
are now many hundreds of thousands burning nightly in our own country
alone.

Davy probably never imagined that his brilliant experiment would soon
play so important a part in the future lighting of the world. He may never
have regarded it as of any practical value. In fact, many years elapsed
before any further attempt was made to utilize the light of the electric arc.
The reason for this is not difficult to discover. The batteries in existence
were crude and gave only their full power for a very short time after the
circuit was closed. They were subject to the very serious defect of rapid
polarization, whereby the activity was at once reduced. A long period
elapsed before this defect was removed. Davy in his experiments had also
noted the very intense heat of the electric arc, and found that but few
substances escaped fusion or volatilization when placed in the heated
stream between the carbon electrodes. Here again he was pioneer in very
important and quite recent electric work, employing the electric furnace,
which has already given rise to several new and valuable industries.
The conduction of electricity along wires naturally led to efforts to
employ it in signalling. As early as 1774 attempts were made by Le Sage, of
Geneva, to apply frictional electricity to telegraphy. His work was followed
before the close of the century by other similar proposals. Volta’s discovery
soon gave a renewed impetus to these efforts. It was easy enough to stop
and start a current in a line of wire connecting two points, but something
more than that was requisite. A good receiver, or means for recognizing the
presence or absence of current in the wire or circuit, did not exist. The art
had to wait for the discovery of the effects of electric current upon magnets
and the production of magnetism by such currents. Curiously, even in 1802
the fact that a wire conveying a current would deflect a compass needle was
observed by Romagnosi, of Trente, but it was afterwards forgotten, and not
until 1819 was any real advance made.
It was then that Oersted, of Copenhagen, showed that a magnet tends to
set itself at right angles to the wire conveying current and that the direction
of turning depends on the direction of the current. The study of the
magnetic effects of electric currents by Arago, Ampère, and the production
of the electro-magnet by Sturgeon, together with the very valuable work of
Henry and others, made possible the completion of the electric telegraph.
This was done by Morse and Vail in America, and almost simultaneously by
workers abroad, but, before Morse had entered the field, Professor Joseph
Henry had exemplified by experiments the working of electric signalling by

electro-magnets over a short line. It was Henry, in fact, who first made a
practically useful electro-magnet of soft iron. The history of the electric
telegraph teaches us that to no single individual is the invention due. The
Morse system had been demonstrated in 1837, but not until 1844 was the
first telegraph line built. It connected Baltimore and Washington, and the
funds for defraying its cost were only obtained from Congress after a severe
struggle. This can easily be understood, for electricity had not up to that
time ever been shown to have any practical usefulness. The success of the
Morse telegraph was soon followed by the establishment of telegraph lines
as a means of communication between all the large cities and populous
districts. Scarcely ten years elapsed before the possibility of a transatlantic
telegraph was mooted. The cable laid in 1858 was a failure. A few words
passed, and then the cable broke down completely. This was found to be
due to defects in construction. A renewed effort to lay a cable was made in
1866, but disappointment again followed: the cable broke in mid-ocean and
the work again ceased. The great task was successfully accomplished in the
following year, and the pluck and pertinacity of those who were staking
their capital, if not their reputations for business sagacity, were amply
rewarded. Even the lost cable of 1866 was found, spliced to a new cable,
and completed soon after as a second working line. The delicate instruments
for the working of these long cables were due to the genius of Sir William
Thomson, now Lord Kelvin, whose other instruments for electrical
measurement have for years been a great factor in securing precision both
in scientific and practical testing. The number of cables joining the Eastern
and Western hemispheres has been increased from time to time, and the
opening of a new cable is now an ordinary occurrence, calling for little or
no especial note.
The introduction of the electric telegraph was followed by the invention
of various signalling systems, the most important being the fire-alarm
telegraph, as suggested by Channing and worked out by Farmer. We now,
also, have automatic clock systems, in which a master clock controls or
gives movement to the hands of distant clock dials by electric currents sent
out over the connecting or circuit wires. Automatic electric signals are made
when fire breaks out in a building, and alarms are similarly rung when a
burglar breaks in. Not only do we have telegraphs which print words and
characters, as in the stock “ticker,” but in the form known as the
telautograph, invented by Dr. Elisha Gray, the sender writes his message,

which writing is at the same time being reproduced at the receiving end of
the line. Even pictures for drawings are “wired” by special instruments. The
desirability of making one wire connecting two points do a large amount of
work, and thus avoiding the addition of new lines, has led to two
remarkable developments of telegraphy. In the duplex, quadruplex, and
multiplex systems several messages may at the same time be traversing a
single wire line without interference one with the other. In the rapid
automatic systems the working capacity of the line is increased by special
automatic transmitting machines and rapid recorders, and the electric
impulses in the line itself follow each other with great speed.
Improvement in this field has by no means ceased, and new systems for
rapid transmission are yet being worked out. The object is to enlarge the
carrying capacity of existing lines connecting large centres of population.
The names of Wheatstone, Stearns, Edison, and Delaney are prominent in
connection with this work. For use in telegraphy the originally crude forms
of voltaic battery, such as Davy used, were replaced by the more perfect
types such as the constant battery of Daniell, the nitric-acid battery of
Grove, dating from 1836, and the carbon battery of Bunsen, first brought
out in 1842. Such was the power of the Grove and Bunsen batteries that
attention was again called to the electric arc and to the possibility of its use
for electric illumination. Accordingly, we find that suggestions were soon
made for electric-arc lamps, to be operated by these more powerful and
constant sources of electric current. The first example of a working type of
an arc lamp was that brought to notice by W. E. Staite, in 1847, and his
description of the lamp and the conditions under which it could be worked
is a remarkably exact and full statement, considering the time of its
appearance. Staite even anticipated the most recent phase of development in
arc lighting, namely, the enclosure of the light in a partially air-tight globe,
to prevent too rapid waste of the carbons by combustion in the air. In a
public address at Newcastle-on-Tyne, in 1847, he advocated the use of the
arc, so enclosed, in mines, as obviating the danger of fire. But it was a long
time before the electric arc acquired any importance as a practical
illuminant. There was, indeed, no hope of its success so long as the current
had to be obtained from batteries consuming chemicals and zinc. The
expense was too great, and the batteries soon became exhausted. In spite of
this fact, occasional exhibitions of arc lighting were made, notably in 1856,
by Lacassagne and Thiers, in the streets of Paris.

For this service they had invented an arc lamp involving what is known
as the differential principle, afterwards applied so extensively to arc lamps.
The length of the arc or the distance between the carbons of the lamp was
controlled with great nicety, and the light thus rendered very steady. Even as
late as 1875 batteries were occasionally used to work single electric arc
lamps for public exhibitions, or for demonstration purposes in the scientific
departments of schools. The discovery of the means of efficiently
generating electricity from mechanical power constitutes, however, the key-
note of all the wonderful electrical work of the closing years of the
nineteenth century. It made electrical energy available at low cost. Michael
Faraday, a most worthy successor of Davy at the Royal Institution, in
studying the relations between electric currents and magnets, made the
exceedingly important observation that a wire, if moved in the field of a
magnet, would yield a current of electricity. Simple as the discovery was, its
effect has been stupendous. Following his science for its own sake, he
unwittingly opened up possibilities of the greatest practical moment. The
fundamental principle of the future dynamo electric machine was
discovered by him. This was in 1831. Faraday’s investigations were so
complete and his deductions so masterly, that little was left to be done by
others. Electro-magnetism was supplemented by magneto-electricity. Both
the electric motor and the dynamo generator were now potentially present
with us. Faraday contented himself with pointing the way, leaving the
technical engineer to follow. In one of Faraday’s experiments a copper disk
mounted on an axis passing through its centre was revolved between the
poles of a large steel magnet. A wire touched the periphery of the disk at a
selected position with respect to the magnet, and another was in connection
with the axis. These wires were united through a galvanometer or
instrument for detecting electric current. A current was noted as present in
the circuit so long as the disk was turned. Here, then, was the embryo
dynamo. The century closed with single dynamo machines of over 5000
horse-power capacity, and with single power stations in which the total
electric generation by such machines is 75,000 to 100,000 horse-power. So
perfect is the modern dynamo that out of 1000 horse-power expended in
driving it, 950 or more may be delivered to the electric line as electric
energy. The electric motor, now so common, is a machine like the dynamo,
in which the principle of action is simply reversed; electric energy delivered
from the lines becomes again mechanical motion or power.

Soon after Faraday’s discoveries in magneto-electricity attempts were
made to construct generators of electricity from power. But the machines
were small, crude, and imperfect, and the results necessarily meagre.
Pixii, in Paris, one year after Faraday’s discovery was announced, made
a machine which embodied in its construction a simple commutator for
giving the currents a single direction of flow. This is the prototype of the
commutators now found on what are called continuous-current dynamos.
After Pixii followed Saxton, Clarke, Wheatstone and Cooke, Estohrer, and
others, but not until 1854 was any very notable improvement made or
suggested. In that year Soren Hjorth, of Copenhagen, described in a patent
specification the principle of causing the electric currents generated to
traverse coils of wire so disposed as to reinforce the magnetic field of the
machine itself. A year subsequently the same idea was again more clearly
set out by Hjorth. This is the principle of the modern self-exciting dynamo,
the field magnets of which, very weak at the start, are built up or
strengthened by the currents from the armature or revolving part of the
machine in which power is consumed to produce electricity.
In 1856 Dr. Werner Siemens, of Berlin, well known as a great pioneer
in the electric arts, brought out the Siemens armature, an innovation more
valuable than any other made up to that time. This was subsequently used in
the powerful machines of Wilde and Ladd. It still survives in magneto call-
bell apparatus for such work as telephone signalling, in exploders for mines
and blasting, and in the simpler types of electroplating dynamos.
The decade between 1860 and 1870 opened a new era in the
construction and working of dynamo machines and motors. It is notable for
two advances of very great value and importance. Dr. Paccinotti, of
Florence, in 1860, described a machine by which true continuous currents
resembling battery currents could be obtained. Up to that time machines
gave either rapidly alternating or fluctuating currents, not steady currents in
one direction. The Paccinotti construction, in modified forms, is now almost
universally employed in dynamo machines, and even where the form is now
quite different the Paccinotti type has been at least the forerunner, and has
undergone modifications to suit special ends in view. Briefly, Paccinotti
made his armature of a ring of iron with iron projections between which the
coils of insulated wire were wound. Although full descriptions of
Paccinotti’s ring armature and commutator were given out in 1864, his

work attracted but little attention until Gramme, in Paris, about 1870,
brought out the relatively perfect Gramme machine. In the mean time the
other great development of the decade took place.
Although Hjorth had, as stated before, put forward the idea that a
dynamo generator might itself furnish currents for magnetizing its own
magnets, this valuable suggestion was not apparently worked out until
1866, when a machine was constructed for Sir Charles Wheatstone. This
appears to have been the first self-exciting machine in existence.
Wheatstone read a paper before the Royal Society in February, 1867, “On
the Augmentation of the Power of a Magnet by the Reaction thereon of
Currents Induced by the Magnet Itself.” This action later became known as
the reaction principle in dynamo machines.
As often happens, the idea occurred to other workers in science almost
simultaneously, and Dr. Werner Siemens also read a paper in Berlin about a
month earlier than that of Wheatstone, clearly describing the reaction
principle. Furthermore, a patent specification had been filed in the British
Patent Office by S. A. Varley, December 24, 1866, clearly showing the
same principle of action, and he was, therefore, the first to put the matter on
record. The time was ripe for the appearance of machines closely
resembling the types now in such extended use. Gramme, in 1870, adopting
a modified form of the Paccinotti ring and commutator, and employing the
reaction principle, first succeeded in producing a highly efficient, compact,
and durable continuous-current dynamo. The Gramme machine was
immediately recognized as a great technical triumph. It was in a sense the
culmination of many years of development, beginning with the early
attempts immediately following Faraday’s discovery, already referred to.
Gramme constructed his revolving armature of a soft iron wire ring, upon
which ring a series of small coils of insulated wire were wound in
successive radial planes. These coils were all connected with a continuous
wire and from the junctions of the coils one with another connections were
taken to a range of copper bars insulated from each other, constituting the
commutator. In 1872 Von Hefner Alteneck, in Berlin, modified the ring
winding of Gramme and produced the “drum winding,” which avoided the
necessity for threading wire through the centre of the iron ring as in the
Gramme construction. The several coils of the drum were still connected, as
in Gramme’s machine, to the successive strips of the commutator.

In modern dynamos and motors the armature, usually constructed of
sheet-iron punchings, is a ring with projections as in Paccinotti’s machine,
and the coils of wire are in most cases wound separately and then placed in
the spaces between the projections, constituting in fact a form of drum
winding. In the early 70’s a few Gramme ring and Siemens drum machines
had been applied to the running of arc lights, one machine for each light.
There were also some Gramme machines in use for electroplating.
At the Centennial Exhibition, held at Philadelphia in 1876, but two
exhibits of electric-lighting apparatus were to be found. Of these one was
the Gramme and the other the Wallace-Farmer exhibit. The Wallace-Farmer
dynamo machine is a type now obsolete. It was not a good design, but the
Wallace exhibit contained other examples reflecting great credit on this
American pioneer in dynamo work. Some of these machines were very
similar in construction to later forms which went into very extensive use.
The large search-lights occasionally used in night illumination during the
exhibitions were operated by the current from Wallace-Farmer machines.
The Gramme exhibit was a remarkable exhibit for its time. Though not
extensive, it was most instructive. There were found in it a dynamo running
an arc lamp; a large machine for electrolytic work, such as electroplating or
electrotyping, and, most novel and interesting of all, one Gramme machine
driven by power was connected to another by a pair of wires and the second
run as a motor. This in turn drove a centrifugal-pump, and raised water
which flowed in a small fall or cataract. A year or two previously the
Gramme machine had been accidentally found to be as excellent an electric
motor as it was a generating dynamo. The crude motors of Jacobi, Froment,
Davenport, Page, Vergnes, Gaume, and many others, were thus rendered
obsolete at a stroke. The first public demonstration of the working of one
Gramme machine by another was made by Fontaine at the Vienna
Exhibition of 1873.
Here, then, was a foreshadowing of the great electric-power
transmission plants of to-day; the suggestion of the electric station
furnishing power as well as light, and, to a less degree, the promise of
future railways using electric power. Replace the centrifugal pump of this
modest exhibit by a turbine wheel, reverse the flow of water so as to cause
it to drive the electric motor so that the machine becomes a dynamo, and, in
like manner, make of the dynamo a motor, and we exemplify in a simple

way recent great enterprises using water-power for the generation of current
to be transmitted over lines to distant electric motors or lights.
The Centennial Exhibition also marks the beginning—the very birth, it
may be said—of an electric invention destined to become, before the close
of the century, a most potent factor in human affairs. The speaking
telephone of Alexander Graham Bell was there exhibited for the first time
to the savants, among whom was the distinguished electrician and scientist
Sir William Thomson. For the first time in the history of the world a
structure of copper wire and iron spoke to a listening ear. Nay, more, it both
listened to the voice of the speaker and repeated the voice at a far-distant
point. The instruments were, moreover, the acme of simplicity. Within a
year many a boy had constructed a pair of telephones at an expenditure for
material of only a few pennies. In its first form the transmitting telephone
was the counterpart of the receiver, and they were reversible in function.
The transmitter was in reality a minute dynamo driven by the aërial voice
waves; the receiver, a vibratory motor worked by the vibratory currents
from the transmitter and reproducing the aërial motions. This arrangement,
most beautiful in theory, was only suited for use on short lines, and was
soon afterwards replaced by various forms of carbon microphone
transmitter, to the production of which many inventors had turned their
attention, notably Edison, Hughes, Blake, and Hunnings. In modern
transmitters the voice wave does not furnish the power to generate the
telephone current, but only controls the flow of an already existing current
from a battery. In this way the effects obtainable may be made sufficiently
powerful for transmission to listeners 1500 miles away.
There is no need to dwell here upon the enormous saving of time
secured by the telephone and the profound effect its introduction has had
upon business and social life. The situation is too palpable. Nevertheless,
few users of this wonderful invention realize how much thought and skill
have been employed in working out the details of exchange switchboards,
of signalling devices, of underground cables and overhead wires, and of the
speaking instruments themselves. Few of those who talk between Boston
and Chicago know that in doing so they have for the exclusive use of their
voices a total of over 1,000,000 pounds of copper wire in the single line.
There probably now exist in the United States alone between 75,000 and
100,000 miles of hard-drawn copper wire for long-distance telephone

service, and over 150,000 miles of wire in underground conduits. There are
upward of three-quarters of a million telephones in the United States, and,
including both overhead and underground lines, a total of more than half a
million miles of wire. Approximately one thousand million conversations
are annually conveyed.
The possibility of sub-oceanic telephoning is frequently discussed, but
the problem thus far is not solved. It involves grave difficulties, and we may
hope that its solution is to be one of the advances which will mark the
twentieth century’s progress.
The advent of the telephone in 1876 seemed to stimulate invention in
the electric field to a remarkable degree. Its immediate commercial success
probably acted also to inspire confidence in other proposed electric
enterprises. Greater attention than ever before began to be given to the
problem of electric lighting. An electric arc lamp, probably the only one in
regular use, had been installed at Dungeness Light-house in 1862, after a
long set of trials and tests. It was fed by a Holmes magneto-electric
machine of the old type, very large and cumbrous for the work. Numerous
changes and improvements had before 1878 been made in arc lamps by
Serrin, Duboscq, and many others. But the display of electric light during
the Paris Exposition of 1878 was the first memorable use of the electric
light on a large scale. The splendid illumination of the Avenue de l’Opéra
was a grand object-lesson. The source of light was the “electric candle” of
Paul Jablochkoff, a Russian engineer. It was a strikingly original and simple
arc lamp. Instead of placing the two carbons point to point, as had been
done in nearly all previous lamps, he placed them side by side, with a strip
of baked kaolin between them. The candle so formed was supported in a
suitable holder, whereby, at the lower end, the two parallel carbons were
connected with the circuit terminals. By a suitable device the arc was
started at the top and burned down. The electric candle seemed to solve the
problem of allowing complicated mechanism for feeding the carbons to be
discarded; but it survived only a short time. Owing to unforeseen
difficulties it was gradually abandoned, after having served a great purpose
in directing the attention of the world to the possibilities of the electric arc
in lighting.
Inventors in America were not idle. By the close of 1878, Brush, of
Cleveland, had brought out his series system of arc lights, including special

dynamos, lamps, etc., and by the middle of 1879 had in operation machines
each capable of maintaining sixteen arc lamps on one wire. This was,
indeed, a great achievement for that time. Weston, of Newark, had also in
operation circuits of arc lamps, and the Thomson-Houston system had just
started in commercial work with eight arc lamps in series from a single
dynamo. Maxim and Fuller, in New York, were working arc lamps from
their machines, and capital was being rapidly invested in new enterprises
for electric lighting. Some of the great electric manufacturing concerns of
to-day had their beginning at that time. Central lighting stations began to be
established in cities, and the use of arc lights in street illumination and in
stores grew rapidly. More perfect forms of arc lamps were invented, better
generating dynamos and regulating apparatus brought out. Factories for arc-
light carbon making were built. The first special electrical exhibition was
held in Paris in 1881. In the early 80’s, also, the business of arc lighting had
become firmly established, and soon the bulk of the work was done under
two of the leading systems. These were afterwards brought together under
one control, thus securing in the apparatus manufactured a combination of
the good features of both. Until about 1892 nearly all the arc lamps in use
were worked under the series system, in which the lights are connected one
after another on a circuit and traversed by the same current. This current has
a standard value, or is a constant current. Sometimes as many as a hundred
lamps were on one wire. As the mains for the supply of incandescent lamps
at constant pressure, or potential, were extended, attention was more
strongly turned to the possibility of working arc lights therefrom.
Within a few years of the close of the century this placing of arc lamps
in branches from the same mains which supply incandescent lamps became
common, and the enclosure of the arc in a partially air-tight globe, a
procedure advocated by Staite, in 1847, was revived by Howard, Marks,
and others for saving carbons and attention to the lamp. The enclosed arc
lamp was also found to be especially adapted to use in branches of the
incandescent lamp circuits, which had in cities become greatly extended.
The increasing employment of alternating currents in the distribution of
electric energy has led also to the use of alternating current arc lamps, and
special current-regulating apparatus is now being applied on a large scale to
extended circuits of these lamps. It can be seen from these facts that the art
is still rapidly progressing and the field ever widening. A little over twenty
years ago practically no arc lamps were used. At the close of the century,

they were numbered by hundreds of thousands. The annual consumption of
carbons in this country has reached two hundred millions.
Almost simultaneously with the beginning of the commercial work of
arc lighting, Edison, in a successful effort to provide a small electric lamp
for general distribution in place of gas, brought to public notice his carbon
filament incandescent lamp.
A considerable amount of progress had previously been made by
various workers in attempting to reduce the volume of light in each lamp
and increase the number of lights for a given power expended. Forms of
incandescent arc lamps, or semi-incandescent lamps, were tried on a
considerable scale abroad, but none have survived. So, also, many attempts
to produce a lamp giving light by pure incandescence of solid conductors
proved for the most part abortive. Edison himself worked for nearly two
years on a lamp based upon the old idea of incandescent platinum strips or
wires, but without success. The announcement of this lamp caused a heavy
drop in gas shares, long before the problem was really solved by a masterly
stroke in his carbon filament lamp. Curiously, the nearest approach to the
carbon filament lamp had been made in 1845, by Starr, an American, who
described in a British patent specification a lamp in which electric current
passed through a thin strip of carbon kept it heated while surrounded by a
glass bulb in which a vacuum was maintained. Starr had exhibited his lamps
to Faraday, in England, and was preparing to construct dynamos to furnish
electric current for them in place of batteries, but sudden death put an end to
his labors. The specification describing his lamp is perhaps the earliest
description of an incandescent lamp of any promise, and the subsequently
recorded ideas of inventors up to the work of Edison seem now to be almost
in the nature of retrograde movements. None of them were successful
commercially. Starr, who was only twenty-five years of age, is reported to
have died of overwork and worry in his efforts to perfect his invention. His
ideas were evidently far in advance of his time.
The Edison lamp differed from those which preceded it in the
extremely small section of the carbon strip rendered hot by the current, and
in the perfection of the vacuum in which it was mounted. The filament was
first made of carbonized paper, and afterwards of bamboo carbon. The
modern incandescent lamp has for years past been provided with a filament
made by a chemical process. The carbon formed is exceedingly

homogeneous and of uniform electric resistance. Edison first exhibited his
lamp in his laboratory at Menlo Park, New Jersey, in December, 1879; but
before it could be properly utilized an enormous amount of work had to be
done. His task was not merely the improvement of an art already existing; it
was the creation of a new art. Special dynamo machines had to be invented
and constructed for working the lamps; switches were needed for
connecting and disconnecting lamps and groups of lamps; meters for
measuring the consumption of electric energy were wanted; safety fuses and
cut-offs had to be provided; electroliers or fixtures to support the lamp were
required; and, lastly, a complete system of underground mains with
appurtenances was a requisite for city plants.
Even the steam-engines for driving the dynamos had to be remodelled
and improved for electric work, and ten years of electric lighting
development did more towards the refinement and perfection of steam-
engines than fifty years preceding. Steadiness of lights meant the
preservation of steady speed in the driving machinery. The Pearl Street
station in New York City was the first installation for the supply of current
for incandescent lighting in a city district. The constant pressure dynamos
were gradually improved and enlarged. The details of all parts of the system
were made more perfect, and in the hands of Edison and others the
incandescent lamps, originally of high cost, were much cheapened and the
quality of the production was greatly improved. Lamps originally cost one
dollar each. The best lamps that are made can be had at present for about
one-fifth that price. Millions of incandescent lamps are annually
manufactured. Great lighting stations furnish the current for the working of
these lamps, some stations containing machinery aggregating many
thousands of horse-power capacity. Not only do these stations furnish
electric energy for the working of arc lamps and incandescent lamps, but, in
addition, for innumerable motors ranging in size from the small desk fan of
one-tenth horse-power up to those of hundreds of horse-power. The larger
sizes replace steam or hydraulic power for elevators, and many are used in
shops and factories for driving machinery such as printing-presses,
machinery tools, and the like.
In spite of the fact that it was well known that a good dynamo when
reversed could be made a source of power, few electric motors were in use
until a considerable time after the establishment of the first lighting stations.

Even in 1884, at the Philadelphia Electrical Exhibition, only a few electric
motors were shown. Not until 1886 or thereafter did the “motor load” of an
electric station begin to be a factor in its business success. The motors
supplied are an advantageous adjunct, inasmuch as they provide a day load,
increasing the output of the station at a time when the lighting load is small
and when the machinery in consequence would, without them, have
remained idle. The growth of the application of electric motors in the
closing years of the century has been phenomenal, even leaving out of
consideration their use in electric railways.
Twenty years ago an electric motor was a curiosity; fifty years ago
crude examples run by batteries were only to be occasionally found in
cabinets of scientific apparatus. Machinery Hall, at the Centennial
Exhibition of 1876, typified the mill of the past, never again to be
reproduced, with its huge engine and lines of heavy shafting and belts
conveying power to the different tools or machines in operation. The
modern mill or factory has its engines and dynamos located wherever
convenient, its electric lines and numerous motors connected thereto, and
each of them either driving comparatively short lines of shafting or attached
to drive single pieces of machinery. The wilderness of belts and pulleys
which used to characterize a factory is gradually being cleared away, and
electric distribution of power substituted. Moreover, the lighting of the
modern mill or factory is done from the same electric plant which
distributes power.
The electric motor has already partly revolutionized the distribution of
power for stationary machinery, but as applied to railways in place of
animal power the revolution is complete. The period which has elapsed
since the first introduction of electric railways is barely a dozen years. It is
true that a few tentative experiments in electric traction were made some
time in advance of 1888, notably by Siemens, in Berlin, in 1879 and 1880,
by Stephen D. Field, by T. A. Edison, at Menlo Park, by J. C. Henry, by
Charles A. Van Depoele, and others. If we look farther back we find efforts
such as that of Farmer, in 1847, to propel railway cars by electric motors
driven by currents from batteries carried on the cars. These efforts were, of
course, doomed to failure, for economical reasons. Electric energy from
primary batteries was too costly, and if it had been cheaper, the types of
electric motor used yielded so small a return of power for the electric

energy spent in driving them that commercial success was out of the
question. These early efforts were, however, instructive, and may now be
regarded as highly suggestive of later work. Traction by the use of storage
batteries carried on an electric car has been tried repeatedly, but appears not
to be able to compete with systems of direct supply from electric lines. The
plan survives, however, in the electric automobile, many of which have
been put into service within a year or two. The electric automobile is not
well fitted for country touring; it is best adapted to cities, where facilities
for charging and caring for the batteries can be had. Moreover, the electric
carriage is of all automobile carriages the most easily controlled, most
ready; it emits no smell or hot gases and is nearly noiseless.
About 1850, Hall, a well-known instrument maker of Boston,
catalogued a small toy electric locomotive dragging a car upon rails which
were insulated and connected with a stationary battery of two Grove cells.
This arrangement was sold as a piece of scientific apparatus, and appears to
be the first example of an electrically driven vehicle connected by rolling
contacts to an immovable energy source. Other early experimenters, such as
Siemens, Field, and Daft, subsequently to Hall, used in actual railway work
the supply by insulated tracks. This was supplanted later by overhead
insulated wires or by the insulated third rail. Siemens & Halske, of Berlin,
used a special form of overhead supply in 1881, and during the electrical
exhibition in Paris in that year, a street tramway line was run by them.
Later, Edison experimented with a third-rail-supply line at Menlo Park; and
at Portrush, in Ireland, an actual railway was put in operation by Siemens &
Halske, using the third-rail system. This was about 1883. The power of the
Portrush railway was that of a water-wheel driving the generating dynamo.
The modern overhead trolley, or under-running trolley, as it is called,
seems to have been first invented by Van Depoele, and used by him in
practical electric railway work about 1886 and thereafter. The universality
of this invention for overhead supply marks the device as a really important
advance in the art of electric traction. Van Depoele was also a pioneer in the
use of an underground conduit, which he employed successfully in Toronto
in 1884. The names of Edward M. Bentley and Walter H. Knight stand out
prominently in connection with the first use of an underground conduit,
tried under their plans in August, 1884, at Cleveland, on the tracks of the
horse-railway company.

We have barely outlined the history of the electric-motor railway up to
the beginning of a period of wonderful development, resulting in the almost
complete replacement by electric traction of horse traction or tramway
lines, all within an interval of scarcely more than ten years.
The year 1888 may be said to mark the beginning of this work, and in
that year the Sprague Company, with Frank J. Sprague at its head, put into
operation the electric line at Richmond, Virginia, using the under-running
trolley. Mr. Sprague had been associated with Edison in early traction work,
and was well known in connection with electric-motor work in general. The
Richmond line was the first large undertaking. It had about thirteen miles of
track, numerous curves, and grades of from three to ten per cent. The
enterprise was one of great hardihood, and but for ample financial backing
and determination to spare no effort or expenditure conducive to success,
must certainly have failed. The motors were too small for the work, and
there had not been found any proper substitute for the metal commutator
brushes on the motors—a source of endless trouble and of an enormous
expense for repairs. Nevertheless, the Richmond installation, kept in
operation as it was in spite of all difficulties, served as an object-lesson, and
had the effect of convincing Mr. Henry M. Whitney and the directors of the
West End Street Railway, of Boston, of the feasibility of equipping the
entire railway system of Boston electrically. Meanwhile the merging of the
Van Depoele and Bentley-Knight interests into the Thomson-Houston
Electric Light Company brought a new factor into the field, the Sprague
interests being likewise merged with the Edison General Electric Company.
The West End Company, with two hundred miles of track in and around
Boston, began to equip its lines in 1888 with the Thomson-Houston plant.
The success of this great undertaking left no doubt of the future of electric
traction. The difficulties which had seriously threatened future success were
gradually removed.
The electric railway progress was so great in the United States that
about January 1, 1891, there were more than two hundred and forty lines in
operation. About thirty thousand horses and mules were replaced by electric
power in the single year of 1891. In 1892 the Thomson-Houston interests
and those of the Edison General Electric Company were merged in the
General Electric Company, an event of unusual importance, as it brought
together the two great competitors in electric traction at that date. Other

electric manufacturers, chief among which was the Westinghouse Company,
also entered the field and became prominent factors in railway extension. In
a few years horse traction in the United States on tramway lines virtually
disappeared. Many cable lines were converted to electric lines, and projects
such as the Boston Subway began to be planned. Not the least of the
advantages of electric traction is the higher speed attainable with safety. The
comfort and cleanliness of the cars, lighted brilliantly at night, and heated in
winter by the same source of energy which is used to propel them, are
important factors.
All these things, together with the great extension of the lines into
suburban and country districts, and the interconnection of the lines of one
district with those of another, cannot fail to have a decidedly beneficial
effect upon the life, habits, and health of the people. While the United
States and Canada have been and still are the theatre of the enormous
advance in electric traction, as in other electric work, many electric car lines
have in recent years been established in Great Britain and on the continent
of Europe. Countries like Japan, Australia, South Africa, and South America
have also in operation many electric trolley lines, and the work is rapidly
extending. Most of this work, even in Europe, has been carried out either by
importation of equipment from America, or by apparatus manufactured
there, but following American practice closely. The bulk of the work has
been done with the overhead wire and under-running trolley, but there are
notable instances of the use of electric conductors in underground slotted
conduits, chief of which are the great systems of street railway in New York
City.
In Chicago the application of motor-cars in trains upon the elevated
railway followed directly upon the practical demonstration at the World’s
Fair of the capabilities of third-rail electric traction on the Intramural
Elevated Railway, and the system is rapidly extending so as to include all
elevated city roads. A few years will doubtless see the great change
accomplished.
The motor-car, or car propelled by its own motors, has also been
introduced upon standard steam roads to a limited extent as a supplement to
steam traction. The earliest of these installations are the one at Nantasket,
Massachusetts, and that between Hartford and New Britain, in Connecticut.
A number of special high-speed lines, using similar plans, have gone into

operation in recent years. The problem of constructing electric motors of
sufficient robustness for heavy work and controlling them effectively was
not an easy one, and the difficulties were increased greatly because of the
placing of the motors under the car body, exposed to wet, to dust and dirt of
road. The advantage of the motor-car, or motor-car train, is that the traction
or hold upon the track increases with the increase of the weight or load
carried. It is thus able to be accelerated rapidly after a stop, and also climb
steep grades without slipping its wheels. Nevertheless, there are
circumstances which favor the employment of a locomotive at the head of a
train, as in steam practice. This is the case in lines where a train of coal or
ore cars is drawn by electric mining locomotives. Many such plants are in
operation, and, at the same time the electric power is used to drive fans for
ventilating, pumps for drainage, electric hoists, etc., besides being used for
lighting the mines. The trains in the tunnels of the Metropolitan
Underground Railway of London have for many years been operated by
steam locomotives with the inevitable escape of steam, foul, suffocating
gases, and more or less soot.
A number of years ago the tunnel of the City and South London
Railway was put into successful operation with electric locomotives
drawing the trains of cars, and the nuisance caused by steam avoided. This
work recalls the early efforts of Field, of Daft, and Bentley and Knight in
providing an electric locomotive for replacing the steam plant of the
elevated roads in New York City. Well-conceived as many of these plans
were, electric traction had not reached a sufficient development, and the
efforts were abandoned after several more or less successful trials. It is now
seen that the motor-car train may advantageously replace the locomotive-
drawn train in such instances as these elevated railways.
The three largest and most powerful electric locomotives ever put into
service are those which are employed to take trains through the Baltimore
and Ohio Railroad tunnel at Baltimore. They have been in service about
seven or eight years, and are fully equal in power to the large steam
locomotives used on steam roads. Frequently trains of cars, including the
steam locomotive itself, are drawn through the tunnel by these huge electric
engines, the fires on the steam machines being for the time checked so as to
prevent fouling the air of the tunnel. There was opened, in London, in 1900,
a new railway called the Central Underground, equipped with twenty-six

electric locomotives for drawing its trains. The electric and power
equipment, which embodied in itself the latest results of American practice,
was also manufactured in America to suit the needs of the road. Other
similar railways are in contemplation in London and in other cities of
Europe. As on the elevated roads in New York City, the replacement of
underground steam traction, where it exists, by electric traction is evidently
only a question of a few years.
An electric railway may exemplify a power-transmission system in
which power is delivered to moving vehicles. But the distances so covered
are not generally more than a few miles from the generating station. Where,
however, abundant water-power exists, as at Niagara, or where fuel is very
expensive and power is to be had only at great distances from the place at
which it is to be used, electricity furnishes the most effective means for
transmission and distribution. Between the years 1880 and 1890 the device
called alternating current transformer was developed to a considerable
degree of perfection. It is, in reality, a modified induction coil, consisting of
copper wire and iron, whereby a current sent through one of its coils will
induce similar currents in the other coils of apparatus. It has the great
advantage of having no moving parts. Faraday, in 1831, discovered the
fundamental principle of the modern transformer. Not only, however, will
the current in one coil of the apparatus generate by induction a new current
in an entirely separate coil or circuit, but by suitably proportioning the
windings we may exchange, as it were, a large low-pressure current for a
small but high-pressure current, or vice versa. This exchange may be made
with a very small percentage of loss of energy. These valuable properties of
the transformer have rendered it of supreme importance in recent electrical
extension. The first use made of it, in 1885–86, was to transform a high-
pressure current into one of low pressure in electric lighting, enabling a
small wire to be used to convey electric energy at high pressure, and
without much loss, to a long distance from the station. This energy at high
pressure reaches the transformer placed within or close to the building to be
lighted. A low-pressure safe current is conveyed from the transformer to the
wires connected to the lamps. In this way a current of two thousand volts,
an unsafe and unsuitable pressure for incandescent lighting, is exchanged
for one of about one hundred volts, which is quite safe. In this way, also, the
supply station is enabled to reach a customer too far away to be supplied

directly with current at one hundred volts, without enormous expense for
copper conductors.
The alternating current transformer not only greatly extended the radius
of supply from a single station, but also enabled the station to be
conveniently located where water and coal could be had without difficulty.
It also permitted the distant water-powers to become sources of electric
energy for lighting, power, or for other service. For example, a water-power
located at a distance of fifty to one hundred miles or more from a city, or
from a large manufacturing centre where cost of fuel is high, may be
utilized as follows: A power-station will be located upon the site of the
water-power, and the dynamos therein will generate electricity at, say, two
thousand volts pressure. By means of step-up transformers this will be
exchanged for a current of thirty thousand volts for transmission over a line
of copper or aluminum wire to the distant consumption area. Here there will
be a set of step-down transformers which will exchange the thirty-thousand-
volt line current for one of so low a pressure as to be safe for local
distribution to lamps, to motors, etc., either stationary or upon a railway.
The same transmission plant may simultaneously supply energy for
lighting, for power, for heat, and for charging storage batteries. It may,
therefore, be employed both day and night.
These long-distance power transmission plants are generally spoken of
as “two-phase,” “three-phase,” or “polyphase” systems. Before 1890 no
such plants existed. A large number of such installations are now working
over distances of a few miles up to one hundred miles. They differ from
what are known as single-phase alternating systems in employing, instead
of a single alternating current, two, three, or more, which are sent over
separate lines, and in which the electric impulses are not simultaneous, but
follow each other in regular succession, overlapping each other’s dead
points, so to speak. Early suggestions of such a plan, about 1880, and
thereafter, by Bailey, Deprez, and others, bore no fruit, and not until Tesla’s
announcement of his polyphase system, in 1888, was much attention given
to the subject. A widespread interest in Tesla’s work was invoked, but
several years elapsed before engineering difficulties were overcome. This
work was done mainly by the technical staffs of the large manufacturing
companies, and it was necessary to be done before any notable power

transmissions on the polyphase system could be established. After 1892 the
growth became very rapid.
The falls of Niagara early attracted the attention of engineers to the
possibility of utilizing at least a fraction of the power. It was seen that
several hundred thousand horse-power might be drawn from it without
materially affecting the fall, itself equivalent to several millions of horse-
power. A gigantic power-station has lately been established at Niagara,
taking water from a distance above the falls and delivering it below the falls
through a long tunnel which forms the tail race. Ten water-wheels, located
in an immense wheel-pit about two hundred feet deep, each wheel of a
capacity of five thousand horse-power, drive large vertical shafts, at the
upper end of which are located the large two-phase dynamos, each of five
thousand horse-power. The electric energy from these machines is in part
raised in pressure by huge transformers for transmission to distant points,
such as the city of Buffalo, and a large portion is delivered to the numerous
manufacturing plants located at moderate distances from the power-station.
Besides the supply of energy for lighting, and for motors, including
railways, other recent uses of electricity to which we have not yet alluded
are splendidly exemplified at Niagara. Davy’s brilliant discovery of the
alkali metals, sodium and potassium, at the opening of the century, showed
the great chemical energy of the electric current. Its actions were afterwards
carefully studied, notably by the illustrious Faraday, whose discoveries in
connection with magnetism and magneto-electricity have been briefly
described. The electric current was found to act as a most potent chemical
force, decomposing and recomposing many chemical compounds,
dissolving and depositing metals. Hence, early in the century arose the art
of electroplating of metals, such as electro-gilding, silver-plating, nickel-
plating, and copper deposition as in electrotyping. These arts are now
practised on a very large scale, and naturally have affected the whole course
of manufacturing methods during the century. Moreover, since the
introduction of dynamo current, electrolysis has come to be employed in
huge plants, not only for separating metals from each other, as in refining
them, but in addition for separating them from their ores, for the
manufacture of chemical compounds before unknown, and for the cheap
production of numerous substances of use in the various arts on a large
scale. Vast quantities of copper are refined, and silver and gold often
obtained from residues in sufficient amount to pay well for the process.

At Niagara also are works for the production of the metal aluminum
from its ores. Similar works exist at other places here and abroad where
power is cheap. This metal, which competes in price with brass, bulk for
bulk, was only obtainable before its electric reduction at $25 to $30 per
pound. The metal sodium is also extracted from soda. A large plant at
Niagara also uses the electric current for the manufacture of chlorine for
bleach, and caustic soda, both from common salt. Chlorate of potassium is
also made at Niagara by electrolysis. The field of electro-chemistry is,
indeed, full of great future possibilities. Large furnaces heated by
electricity, a single one of which will consume more than a thousand horse-
power, exist at Niagara. In these furnaces is manufactured from coke and
sand, by the Acheson process, an abrasive material called carborundum,
which is almost as hard as diamond, but quite low in cost. It is made into
slabs and into wheels for grinding hard substances. The electric furnace
furnishes also the means for producing artificial plumbago, or graphite,
almost perfectly pure, the raw material being coke powder.
A large amount of power from Niagara is also consumed for the
production in special electric arc furnaces of carbide of calcium from coke
and lime. This is the source of acetylene gas, the new illuminant, which is
generated when water is brought into contact with the carbide. The high
temperature of the electric furnace thus renders possible chemical actions
which under ordinary furnace heat would not take place. Henri Moissan, a
French scientist, well known for his brilliant researches in electric furnace
work, has even shown that real diamonds can be made under special
conditions in the electric furnace. He has, in fact, probably practised in a
small way what has occurred on a grand scale in nature, resulting in
diamond fields such as those at Kimberley. One problem less is thus left to
be solved. The electro-chemical and kindred arts are practised not alone at
Niagara, but at many other places where power is cheap. Extensive plants
have grown up, mostly within the five years before the close of the century.
All of the great developments in this field have come about within the last
decade.
The use of electricity for heating is not confined to electric furnaces, in
which the exceedingly high temperature obtainable is the factor giving rise
to success. While it is not likely that electricity will soon be used for
general heating, special instances, such as the warming of electric cars in

winter by electric heaters, the operation of cooking appliances by electric
current, the heating of sad-irons and the like, give evidence of the
possibilities should there ever be found means for the generation of electric
energy from fuel with such high efficiency as eighty per cent. or more.
Present methods give, under most favorable conditions, barely ten per cent.,
ninety per cent. of the energy value of the fuel being unavoidably wasted.
Another application of the heating power of electric currents is found in
the Thomson electric welding process, the development of which has
practically taken place in the past ten years. In this process an exceedingly
large current, at very low electric pressure, traverses a joint between two
pieces of metal to be united. It heats the joint to fusion or softening; the
pieces are pushed together and welded. Here the heat is generated in the
solid metal, for at no time during the operation are the pieces separated. The
current is usually obtained from a welding transformer, an example of an
extreme type of step-down transformer. Current at several hundred volts
passed into the primary winding is exchanged for an enormous current at
only two or three volts in the welding circuit in which the work is done. The
present uses of this electric welding process are numerous and varied.
Pieces of most of the metals and alloys, before regarded as unweldable, are
capable of being joined not only to pieces of the same metal, but also to
different metals. Electric welding is applied on the large scale, making
joints in wires or rods, for welding wagon and carriage wheel tires, for
making barrel-hoops and bands for pails, for axles of vehicles, and for
carriage framing. It has given rise to special manufactures, such as
electrically welded steel pipe or tube, wire fencing, etc. It is used for
welding together the joints of steel car-rails, for welding teeth in saws, for
making many parts of bicycles, and in tool making. An instance of its
peculiar adaptability to unusual conditions is the welding of the iron bands
embedded within the body of a rubber vehicle tire for holding the tire in
place. For this purpose the electric weld has been found almost essential.
Another branch of electric development concerns the storage of
electricity. The storage battery is based upon principles discovered by
Gaston Planté, and applied, since 1881, by Brush, by Faure, and others.
Some of the larger lighting stations employ as reservoirs of electric energy
large batteries charged by surplus dynamo current. This is afterwards drawn
upon when the consumer’s load is heavy, as during the evening. The storage

battery is, however, a heavy, cumbrous apparatus, of limited life, easily
destroyed unless guarded with skill. If a form not possessing these faults be
ever found, the field of possible application is almost limitless.
The above by no means complete account of the progress in electric
applications during the century just closed should properly be supplemented
by an account of the accompanying great advances regarded from the
purely scientific aspect. It is, however, only possible to make a brief
reference thereto within the limits of this article. The scientific study of
electricity and the application of mathematical methods in its treatment has
kept busy a host of workers and drawn upon the resources of the ablest
minds the age has produced. Gauss, Weber, Ampère, Faraday, Maxwell,
Helmholtz, are no longer with us. Of the early founders of the science we
have yet such men as Lord Kelvin, formerly Sir William Thomson, Mascart,
and others, still zealous in scientific work. Following them are a large
number, notable for valuable contributions to the progress of electrical
science, in discoveries, in research, and in mathematical treatment of the
various problems presented. Modern magnetism took form in the hands of
Rowland, Hopkinson, Ewing, and many other able workers. Maxwell’s
electro-magnetic theory of light is confirmed by the brilliant researches of
the late Dr. Hertz, too early lost to science. Hertz proved that all luminous
phenomena are in essence electrical. The wireless telegraphy of to-day is a
direct outcome of Hertz’s experiments on electric waves. It is but little more
than ten years since Hertz announced his results to the world. His work,
supplemented by that of Branly, Lodge, Marconi, and others, made wireless
telegraphy a possibility.
The wonderful X-ray, and the rich scientific harvest which has
followed the discovery by Röntgen of invisible radiation from a vacuum
tube, was preceded by much investigation of the effects of electric
discharges in vacuum tubes, and Hittorf, followed by Crookes, had given
special study to these effects in very high or nearly perfect vacua. Crookes,
though especially enriching science by his work, missed the peculiar X-ray,
which, nevertheless, must have been emitted from many of his vacuum
tubes, not only in his hands, but in those of subsequent students. It was as
late as 1896 that Röntgen announced his discovery. Since that time several
other sources of invisible radiation have been discovered, more or less
similar in effect to the radiations from a vacuum tube, but emitted, singular

as the fact is, from rare substances extracted from certain minerals. Leaving
out of consideration the great value of the X-ray to physicians and surgeons,
its effect in stimulating scientific inquiry has almost been incalculable. The
renewed study of effects of electric discharge in vacuum tubes has already,
in the work of such investigators as Lenard, J. J. Thomson, and others,
apparently carried the subdivision of matter far beyond the time-honored
chemical atom, and has gone far towards showing the essential unity of all
the chemical elements. It is as unlikely that the mystery of the material
universe will ever be completely solved as it is that we can gain an adequate
conception of infinite space or time. But we can at least extend the range of
our mental vision of the processes of nature as we do our real vision into
space depths by the telescope and spectroscope. There can now be no
question that electric conditions and actions are more fundamental than
many hitherto so regarded.
The nineteenth century closed with many important problems in
electrical science unsolved. What great or far-reaching discoveries are yet in
store, who can tell? What valuable practical developments are to come, who
can predict? The electrical progress has been great—very great—but after
all only a part of that grander advance in so many other fields. The hands of
man are strengthened by the control of mighty forces. His electric lines
traverse the mountain passes as well as the plains. His electric railway
scales the Jungfrau. But he still spends his best effort, and has always done
so, in the construction and equipment of his engines of destruction, and now
exhausts the mines of the world of valuable metals, for ships of war, whose
ultimate goal is the bottom of the sea. In this also electricity is made to play
an increasingly important part. It trains the guns, loads them, fires them. It
works the signals and the search-lights. It ventilates the ship, blows the
fires, and lights the dark spaces. Perhaps all this is necessary now, and, if
so, well. But if a fraction of the vast expenditure entailed were turned to the
encouragement of advance in the arts and employments of peace in the
twentieth century, can it be doubted that, at the close, the nineteenth century
might come to be regarded, in spite of its achievements, as a rather
wasteful, semi-barbarous transition period?

Elihu Thomson.

PHYSICS

On theJanuary 7, 1610, Galileo, turning his telescope towards Jupiter, was
first to see the beautiful system of that planet in which the
universe is epitomized. He had already studied the variegated surface of the
moon, and he had seen the spots upon the sun. A little later, in spite of the
feeble power of his instrument, he had discovered that the sun rotates upon
an axis, and something of the wonderful nature of the planet Saturn had
been revealed to him. The overwhelming evidence thus afforded of the truth
of the hypothesis of Copernicus made him its chief exponent. The time had
come for man to know, as he had never known or even dreamed before, his
true relation to the universe of which he was so insignificant a part. In a
single year nearly all of these capital discoveries were made. It was truly an
era of intellectual expansion; never before and never since has man’s
intellectual horizon enlarged with such enormous rapidity. One needs little
imagination to share with this ardent philosopher the enthusiasm of the
moment when, because some, fearing the evidence of their senses, refused
to look through the slender tube, he wrote to Kepler: “Oh, my dear Kepler,
how I wish we could have one hearty laugh together!... Why are you not
here? What shouts of laughter we should have at this glorious folly!”

Galileo died in 1642, and in the same year Newton was born. When
twenty-four years old he “began to think of gravity extending to the orb of
the moon,” and before the end of the century he had discovered and
established the great law of universal gravitation. Thus, at the end of the
seventeenth century, the foundations of modern physics were in place.
During the eighteenth century they were much built upon, but it was the
nineteenth that witnessed not only the greatest advance in detail, but the
most important generalizations made since the time of Galileo and Newton.