HALF HOURS

                                  WITH

                           MODERN SCIENTISTS.


                          LECTURES AND ESSAYS


                                   BY

           PROFS. HUXLEY, BARKER, STIRLING, COPE AND TYNDALL.


                                  WITH


                         A GENERAL INTRODUCTION


                                   BY

                       NOAH PORTER, D.D., LL.D.,

                       PRESIDENT OF YALE COLLEGE.



                             FIRST SERIES.


[Illustration]



                           NEW HAVEN, CONN.:
                      CHARLES C. CHATFIELD & CO.,
                                 1872.


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       Entered according to act of Congress, in the year 1872, by

                      CHARLES C. CHATFIELD & CO.,

    In the Office of the Librarian of Congress, at Washington, D. C.
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             NEW HAVEN, CONN.:
    THE COLLEGE COURANT PRINT.
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            Electrotyped by E. B. Sheldon, New Haven, Conn.


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                               CONTENTS.

            GENERAL INTRODUCTION. BY PREST. PORTER,       v

            ON THE PHYSICAL BASIS OF LIFE.                1
              PROF. T. H. HUXLEY,

            CORRELATION OF VITAL AND PHYSICAL            37
              FORCES.
              PROF. G. F. BARKER, M.D.,

            AS REGARDS PROTOPLASM—REPLY TO HUXLEY.       73
              JAMES HUTCHISON STIRLING,

            ON THE HYPOTHESIS OF EVOLUTION.             145
              PROF. E. D. COPE,

            SCIENTIFIC ADDRESSES.

            ON THE METHODS AND TENDENCIES OF            219
              PHYSICAL INVESTIGATION,

            ON HAZE AND DUST,                           234

            ON THE SCIENTIFIC USE OF THE                247
              IMAGINATION,

            PROF. JOHN TYNDALL, LL.D., F.R.S.,          217


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 INTRODUCTION TO THE NEW EDITION OF HALF HOURS WITH MODERN SCIENTISTS.


The title of this Series of Essays—_Half Hours with Modern
Scientists_—suggests a variety of thoughts, some of which may not be
inappropriate for a brief introduction to a new edition. _Scientist_ is
a modern appellation which has been specially selected to designate a
devotee to one or more branches of physical science. Strictly
interpreted it might properly be applied to the student of any
department of knowledge when prosecuted in a scientific method, but for
convenience it is limited to the student of some branch of physics. It
is not thereby conceded that nature, _i.e._, physical or material nature
is any more legitimately or exclusively the field for scientific
enquiries than spirit, or that whether the objects of science are
material or spiritual, the assumptions and processes of science
themselves should not be subjected to scientific analysis and
justification. There are so-called philosophers who adopt both these
conclusions. There are those who reason and dogmatize as though nature
were synonymous with matter, or as though spirit, if there be such an
essence, must be conceived and explained after the principles and
analogies of matter;—others assume that a science of scientific method
can be nothing better than the mist or moonshine which they vilify by
the name of metaphysics. But unfortunately for such opinions the fact is
constantly forced upon the attention of scientists of every description,
that the agent by which they examine matter is more than matter, and
that this agent, whatever be its substance, asserts its prerogatives to
determine the conceptions which the scientist forms of matter as well as
to the methods by which he investigates material properties. Even the
positivist philosopher who not only denounces metaphysics as
illegitimate, but also contends that the metaphysical era of human
inquiry, has in the development of scientific progress been outgrown
like the measles, which is experienced but once in a life-time; finds
when his positivist theory is brought to the test that positivism itself
in its very problem and its solutions, is but the last adopted
metaphysical theory of science.

We also notice that it is very difficult, if not impossible, for the
inquisitive scientist to limit himself strictly to the object-matter of
his own chosen field, and not to enquire more or less earnestly—not
infrequently to dogmatize more or less positively—respecting the results
of other sciences and even respecting the foundations and processes of
scientific inquiry itself. Thus Mr. Huxley in the first Essay of this
Series on _The Physical Basis of Life_, leaves the discussion of his
appropriate theme in order to deliver sundry very positive and
pronounced assertions respecting the “limits of philosophical inquiry,”
and quotes with manifest satisfaction a dictum of David Hume that is
sufficiently dogmatic and positive, as to what these limits are. In more
than one of his Lay sermons, he rushes headlong into the most pronounced
assertions in respect to the nature of matter and of spirit. The
eloquent Tyndall, in No. 5, expounds at length _The Methods and
Tendencies of Physical Investigation_ and discourses eloquently, if
occasionally somewhat poetically, of _The Scientific use of the
Imagination_. But Messrs. Huxley and Tyndall are eminent examples of
scientists who are severely and successfully devoted respectively to
physiology and the higher physics. No one will contend that they have
not faithfully cultivated their appropriate fields of inquiry. The fact
that neither can be content to confine himself within his special field,
forcibly illustrates the tendency of every modern science to concern
itself with its relations to its neighbors, and the unresistible
necessity which forces the most rigid physicist to become a
metaphysician in spite of himself. So much for the appellation
“_Scientists_.”

“_Half Hours_” suggests the very natural inquiry—What can a scientist
communicate in half an hour, especially to a reader who may be ignorant
of the elements of the science which he would expound? Does not the
phrase _Half Hours with Modern Scientists_ stultify itself and suggest
the folly of any attempt to treat of science with effect in a series of
essays? In reply we would ask the attention of the reader to the
following considerations.

The tendency is universal among the scientific men of all nations, to
present the principles of science in such brief summaries or statements
as may bring them within the reach of common readers. The tendency
indicates that there is a large body of readers who are so far
instructed in the elements of science as to be able to understand these
summaries. In England, Germany, France and this country such brief
essays are abundant, either in the form of contributions to popular and
scientific journals, or in that of popular lectures, or in that of brief
manuals, or of monographs on separate topics; especially such topics as
are novel, or are interesting to the public for their theoretic
brilliancy, or their applications to industry and art.

These essays need not be and they are not always superficial, because
they are brief. They often are the more profound on account of their
conciseness, as when they contain a condensed summary of the main
principles of the art or science in question, or a brief history of the
successive experiments which have issued in some brilliant discovery.
These essays are very generally read, even though they are both concise
and profound. But they could not be read even though they were less
profound than they are, were there not provided a numerous company of
readers who are sufficiently instructed in science to appreciate them.
That such a body of readers exists in the countries referred to, is
easily explained by the existence of public schools and schools of
science and technology, by the enormous extension of the knowledge of
machinery, engineering, mining, dyeing, etc., etc., all of which imply a
more or less distinct recognition of scientific principles and stimulate
the curiosity in regard to scientific truth. Popular lectures also,
illustrated by experiments, have been repeated before thousands of
excited listeners, and the eager and inventive minds of multitudes of
ingenious youths have been trained by this distribution of science, to
the capacity to comprehend the compact and pointed scientific essay,
even though it taxes the attention and suspends the breath for a
half-hour by its closeness and severity.

The fact is also worthy of notice, that many of the ablest scientists of
our times have made a special study of the art of expounding and
presenting scientific truth. Some of them have schooled themselves to
that lucid and orderly method by which a science seems to spring into
being a second time, under the creative hand of its skilful expositor.
Others have made a special study of philosophic diction. Others have
learned how to adorn scientific truth with the embellishments of an
affluent imagination. Some of the ablest writers of our time are found
among the devotees of physical science. That a few scientific writers
and lecturers may have exemplified some of the most offensive features
of the demagogue and the sophist cannot be denied, but we may not forget
that many have attained to the consummate skill of the accomplished
essayist and impressive and eloquent orator.

One advantage cannot be denied of this now popular and established
method of setting forth scientific truth, viz., that it prescribes a
convenient method of bringing into contrast the arguments _for_ and
_against_ any disputed position in science. If materialism can furnish
its ready advocate with a convenient vehicle for its ready diffusion,
the antagonist theory can avail itself of a similar vehicle for the
communication of the decisive and pungent reply. The one is certain to
call forth the other, and if the two are present side by side in the
same series, so much the better is it for the truth and so much the
worse for the error. The teacher before his class, the lecturer in the
presence of his audience, has the argument usually to himself; he allows
few questionings and admits no reply. An erroneous theory may entrench
itself within a folio against arguments which would annihilate its
positions if these were condensed in a tract.

This consideration should dispel all the alarm that is felt by the
defenders of religion in view of the general diffusion of popular
scientific treatises. The brief statement of a false or groundless
scientific theory, even by its defender, is often its most effectual
refutation. A magnificently imposing argument often shrinks into
insignificance when its advocate is forced to state its substance in a
compact and close-jointed outline. The articulations are seen to be
defective, the joints do not fit one another, the coherence is
conspicuously wanting. Let then error do its utmost in the field of
science. Its deficient data and its illogical processes are certain to
be exposed, sometimes even by its own advocates. If this does not happen
the defender of that scientific truth which seems to be essential to the
teachings and faiths of religion, must scrutinize its reasonings by the
rules and methods of scientific inquiry. If science seems to be hostile
to religion, this very seeming should arouse the defender of Theism and
Christianity to examine into the grounds both by the light and methods
which are appropriate to science itself. The more brief and compact and
popular is the argument which he is to refute, the more feasible is the
task of exposure and reply. Only let this be a cardinal maxim with the
defender of the truth, that whatever is scientifically defended and
maintained must be scientifically refuted and overthrown. The great
Master of our faith never uttered a more comprehensive or a grander
maxim than the memorable words, “_To this end was I born and for this
cause came I into the world, that I should bear witness unto the truth.
Everyone that is of the truth heareth my voice._” It would be easy to
show that the belief in moral and religious truth and the freedom in
searching for and defending it which was inspired by these words have
been most efficient in training the human mind to that faith in the
results of scientific investigation which characterize the modern
scientist. That Christian believer must either have a very imperfect
view of the spirit of his own faith, or a very narrow conception of the
evidences and the effect of its teachings, who imagines that the freest
spirit of scientific inquiry, or the most penetrating insight into the
secrets of matter or of spirit can have any other consequence than to
strengthen and brighten the evidence for Christian truth.

                                                                   N. P.

    YALE COLLEGE, _May_, 1872.


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                  PUBLISHERS’ NOTE TO SECOND EDITION.


The five lectures embodied in this First Series of Half Hours with
Modern Scientists were first published as Nos. I.—V. of the University
Scientific Series. In this series the publishers have aimed to give to
the public in a cheap pamphlet form, the advance thought in the
Scientific world. The intrinsic value of these lectures has created a
very general desire to have them put in a permanent form. They therefore
have brought them out in this style. Each five succeeding numbers of
this celebrated series will be printed and bound in uniform style with
this volume, and be designated as second series, third series, and so
on. Henceforth it will be the design of the publishers to give
preference to those lectures and essays of American scientists which
contain original research and discovery, rather than to reprinting from
European sources. The lectures in the second series will be (1) On
Natural Selection as Applied to Man, by Alfred Russel Wallace; (2) three
profoundly interesting lectures on Spectrum Analysis, by Profs. Roscoe,
Huggins, and Lockyer; (3) the Sun and its Different Atmospheres, a
lecture by Prof. C. A. Young, Ph.D., of Dartmouth College; (4) the Earth
a great Magnet, by Prof. A. M. Mayer, Ph.D., of Stevens Institute; and
(5) the Mysteries of the Voice and Ear, by Prof. Ogden N. Rood, of
Columbia College. The last three lectures contain many original
discoveries and brilliant experiments, and are finely illustrated.


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                    _ON THE PHYSICAL BASIS OF LIFE._
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                             INTRODUCTION.


The following remarkable discourse was originally delivered in
Edinburgh, November 18th, 1868, as the first of a series of Sunday
evening addresses, upon non-religious topics, instituted by the Rev. J.
Cranbrook. It was subsequently published in London as the leading
article in the _Fortnightly Review_, for February, 1869, and attracted
so much attention that five editions of that number of the magazine have
already been issued. It is now re-printed in this country, in permanent
form, for the first time, and will doubtless prove of great interest to
American readers. The author is Thomas Henry Huxley, of London,
Professor of Natural History in the Royal School of Mines, and of
Comparative Anatomy and Physiology in the Royal College of Surgeons. He
is also President of the Geological Society of London. Although
comparatively a young man, his numerous and valuable contributions to
Natural Science entitle him to be considered one of the first of living
Naturalists, especially in the departments of Zoölogy and Paleontology,
to which he has mainly devoted himself. He is undoubtedly the ablest
English advocate of Darwin’s theory of the Origin of Species,
particularly with reference to its application to the human race, which
he believes to be nearly related to the higher apes. It is, indeed,
through his discussion of this question that he is, perhaps, best known
to the general public, as his late work entitled “Man’s Place in
Nature,” and other writings on similar topics, have been very widely
read in this country and in Europe. In the present lecture Professor
Huxley discusses a kindred subject of no less interest and importance,
and should have an equally candid hearing.

YALE COLLEGE, _March_ 30_th_, 1869.


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                     On the Physical Basis of Life.


In order to make the title of this discourse generally intelligible, I
have translated the term “Protoplasm,” which is the scientific name of
the substance of which I am about to speak, by the words “the physical
basis of life.” I suppose that, to many, the idea that there is such a
thing as a physical basis, or matter, of life may be novel—so widely
spread is the conception of life as a something which works through
matter, but is independent of it; and even those who are aware that
matter and life are inseparably connected, may not be prepared for the
conclusion plainly suggested by the phrase “the physical basis or matter
of life,” that there is some one kind of matter which is common to all
living beings, and that their endless diversities are bound together by
a physical, as well as an ideal, unity. In fact, when first apprehended,
such a doctrine as this appears almost shocking to common sense. What,
truly, can seem to be more obviously different from one another in
faculty, in form, and in substance, than the various kinds of living
beings? What community of faculty can there be between the
brightly-colored lichen, which so nearly resembles a mere mineral
incrustation of the bare rock on which it grows, and the painter, to
whom it is instinct with beauty, or the botanist, whom it feeds with
knowledge?

Again, think of the microscopic fungus—a mere infinitesimal ovoid
particle, which finds space and duration enough to multiply into
countless millions in the body of a living fly; and then of the wealth
of foliage, the luxuriance of flower and fruit, which lies between this
bald sketch of a plant and the giant pine of California, towering to the
dimensions of a cathedral spire, or the Indian fig, which covers acres
with its profound shadow, and endures while nations and empires come and
go around its vast circumference! Or, turning to the other half of the
world of life, picture to yourselves the great finner whale, hugest of
beasts that live, or have lived, disporting his eighty or ninety feet of
bone, muscle and blubber, with easy roll, among waves in which the
stoutest ship that ever left dockyard would founder hopelessly; and
contrast him with the invisible animalcules—mere gelatinous specks,
multitudes of which could, in fact, dance upon the point of a needle
with the same ease as the angels of the schoolmen could, in imagination.
With these images before your minds, you may well ask what community of
form, or structure, is there between the animalcule and the whale, or
between the fungus and fig-tree? And, _a fortiori_, between all four?

Finally, if we regard substance, or material composition, what hidden
bond can connect the flower which a girl wears in her hair and the blood
which courses through her youthful veins; or, what is there in common
between the dense and resisting mass of the oak, or the strong fabric of
the tortoise, and those broad disks of glassy jelly which may be seen
pulsating through the waters of a calm sea, but which drain away to mere
films in the hand which raises them out of their element? Such
objections as these must, I think, arise in the mind of every one who
ponders, for the first time, upon the conception of a single physical
basis of life underlying all the diversities of vital existence; but I
propose to demonstrate to you that, notwithstanding these apparent
difficulties, a threefold unity—namely, a unity of power or faculty, a
unity of form, and a unity of substantial composition—does pervade the
whole living world. No very abstruse argumentation is needed, in the
first place, to prove that the powers, or faculties, of all kinds of
living matter, diverse as they may be in degree, are substantially
similar in kind. Goethe has condensed a survey of all the powers of
mankind into the well-known epigram:

    “Warum treibt sich das Volk so und schreit? Es will sich
    ernähren Kinder zeugen, und sie nähren so gut es vermag.

                  *       *       *       *       *

    Weiter bringt es kein Mensch, stell’ er sich, wie er auch will.”

In physiological language this means, that all the multifarious and
complicated activities of man are comprehensible under three categories.
Either they are immediately directed towards the maintenance and
development of the body, or they effect transitory changes in the
relative positions of parts of the body, or they tend towards the
continuance of the species. Even those manifestations of intellect, of
feeling, and of will, which we rightly name the higher faculties, are
not excluded from this classification, inasmuch as to every one but the
subject of them, they are known only as transitory changes in the
relative positions of parts of the body. Speech, gesture, and every
other form of human action are, in the long run, resolvable into
muscular contraction, and muscular contraction is but a transitory
change in the relative positions of the parts of a muscle. But the
scheme, which is large enough to embrace the activities of the highest
form of life, covers all those of the lower creatures. The lowest plant,
or animalcule, feeds, grows and reproduces its kind. In addition, all
animals manifest those transitory changes of form which we class under
irritability and contractility; and it is more than probable, that when
the vegetable world is thoroughly explored, we shall find all plants in
possession of the same powers, at one time or other of their existence.
I am not now alluding to such phenomena, at once rare and conspicuous,
as those exhibited by the leaflets of the sensitive plant, or the
stamens of the barberry, but to much more widely-spread, and, at the
same time, more subtle and hidden, manifestations of vegetable
contractility. You are doubtless aware that the common nettle owes its
stinging property to the innumerable stiff and needle-like, though
exquisitely delicate, hairs which cover its surface. Each
stinging-needle tapers from a broad base to a slender summit, which,
though rounded at the end, is of such microscopic fineness that it
readily penetrates, and breaks off in, the skin. The whole hair consists
of a very delicate outer case of wood, closely applied to the inner
surface of which is a layer of semi-fluid matter, full of innumerable
granules of extreme minuteness. This semi-fluid lining is protoplasm,
which thus constitutes a kind of bag, full of a limpid liquid, and
roughly corresponding in form with the interior of the hair which it
fills. When viewed with a sufficiently high magnifying power, the
protoplasmic layer of the nettle hair is seen to be in a condition of
unceasing activity. Local contractions of the whole thickness of its
substance pass slowly and gradually from point to point, and give rise
to the appearance of progressive waves, just as the bending of
successive stalks of corn by a breeze produces the apparent billows of a
corn-field. But, in addition to these movements, and independently of
them, the granules are driven, in relatively rapid streams, through
channels in the protoplasm which seem to have a considerable amount of
persistence. Most commonly, the currents in adjacent parts of the
protoplasm take similar directions; and, thus, there is a general stream
up one side of the hair and down the other. But this does not prevent
the existence of partial currents which take different routes; and,
sometimes, trains of granules may be seen coursing swiftly in opposite
directions, within a twenty-thousandth of an inch of one another; while,
occasionally, opposite streams come into direct collision, and, after a
longer or shorter struggle, one predominates. The cause of these
currents seem to lie in contractions of the protoplasm which bounds the
channels in which they flow, but which are so minute that the best
microscopes show only their effects, and not themselves.

The spectacle afforded by the wonderful energies prisoned within the
compass of the microscopic hair of a plant, which we commonly regard as
a merely passive organism, is not easily forgotten by one who has
watched its display continued hour after hour, without pause or sign of
weakening. The possible complexity of many other organic forms,
seemingly as simple as the protoplasm of the nettle, dawns upon one; and
the comparison of such a protoplasm to a body with an internal
circulation, which has been put forward by an eminent physiologist,
loses much of its startling character. Currents similar to those of the
hairs of the nettle have been observed in a great multitude of very
different plants, and weighty authorities have suggested that they
probably occur, in more or less perfection, in all young vegetable
cells. If such be the case, the wonderful noonday silence of a tropical
forest is, after all, due only to the dullness of our hearing; and could
our ears catch the murmur of these tiny maelstroms, as they whirl in the
innumerable myriads of living cells which constitute each tree, we
should be stunned, as with the roar of a great city.

Among the lower plants, it is the rule rather than the exception, that
contractility should be still more openly manifested at some periods of
their existence. The protoplasm of _Algæ_ and _Fungi_ becomes, under
many circumstances, partially, or completely, freed from its woody case,
and exhibits movements of its whole mass, or is propelled by the
contractility of one or more hair-like prolongations of its body, which
are called vibratile cilia. And, so far as the conditions of the
manifestation of the phenomena of contractility have yet been studied,
they are the same for the plant as for the animal. Heat and electric
shocks influence both, and in the same way, though it may be in
different degrees. It is by no means my intention to suggest that there
is no difference in faculty between the lowest plant and the highest, or
between plants and animals. But the difference between the powers of the
lowest plant, or animal, and those of the highest is one of degree, not
of kind, and depends, as Milne-Edwards long ago so well pointed out,
upon the extent to which the principle of the division of labor is
carried out in the living economy. In the lowest organism all parts are
competent to perform all functions, and one and the same portion of
protoplasm may successively take on the function of feeding, moving, or
reproducing apparatus. In the highest, on the contrary, a great number
of parts combine to perform each function, each part doing its allotted
share of the work with great accuracy and efficiency, but being useless
for any other purpose. On the other hand, notwithstanding all the
fundamental resemblances which exist between the powers of the
protoplasm in plants and in animals, they present a striking difference
(to which I shall advert more at length presently,) in the fact that
plants can manufacture fresh protoplasm out of mineral compounds,
whereas animals are obliged to procure it ready-made, and hence, in the
long run, depend upon plants. Upon what condition this difference in the
powers of the two great divisions of the world of life depends, nothing
is at present known.

With such qualification as arises out of the last-mentioned fact, it may
be truly said that the acts of all living things are fundamentally one.
Is any such unity predicable of their forms? Let us seek in easily
verified facts for a reply to this question. If a drop of blood be drawn
by pricking one’s finger, and viewed with proper precautions and under a
sufficiently high microscopic power, there will be seen, among the
innumerable multitude of little, circular, discoidal bodies, or
corpuscles, which float in it and give it its color, a comparatively
small number of colorless corpuscles, of somewhat larger size and very
irregular shape. If the drop of blood be kept at the temperature of the
body, these colorless corpuscles will be seen to exhibit a marvelous
activity, changing their forms with great rapidity, drawing in and
thrusting out prolongations of their substance, and creeping about as if
they were independent organisms. The substance which is thus active is a
mass of protoplasm, and its activity differs in detail, rather than in
principle, from that of the protoplasm of the nettle. Under sundry
circumstances the corpuscle dies and becomes distended into a round
mass, in the midst of which is seen a smaller spherical body, which
existed, but was more or less hidden, in the living corpuscle, and is
called its _nucleus_. Corpuscles of essentially similar structure are to
be found in the skin, in the lining of the mouth, and scattered through
the whole frame work of the body. Nay, more; in the earliest condition
of the human organism, in that state in which it has just become
distinguishable from the egg in which it arises, it is nothing but an
aggregation of such corpuscles, and every organ of the body was, once,
no more than such an aggregation. Thus a nucleated mass of protoplasm
turns out to be what may be termed the structural unit of the human
body. As a matter of fact, the body, in its earliest state, is a mere
multiple of such units; and, in its perfect condition, it is a multiple
of such units, variously modified. But does the formula which expresses
the essential structural character of the highest animal cover all the
rest, as the statement of its powers and faculties covered that of all
others? Very nearly. Beast and fowl, reptile and fish, mollusk, worm,
and polype, are all composed of structural units of the same character,
namely, masses of protoplasm with a nucleus. There are sundry very low
animals, each of which, structurally, is a mere colorless
blood-corpuscle, leading an independent life. But, at the very bottom of
the animal scale, even this simplicity becomes simplified, and all the
phenomena of life are manifested by a particle of protoplasm without a
nucleus. Nor are such organisms insignificant by reason of their want of
complexity. It is a fair question whether the protoplasm of those
simplest forms of life, which people an immense extent of the bottom of
the sea, would not outweigh that of all the higher living beings which
inhabit the land, put together. And in ancient times, no less than at
the present day, such living beings as these have been the greatest of
rock builders.

What has been said of the animal world is no less true of plants.
Imbedded in the protoplasm at the broad, or attached, end of the nettle
hair, there lies a spheroidal nucleus. Careful examination further
proves that the whole substance of the nettle is made up of a repetition
of such masses of nucleated protoplasm, each contained in a wooden case,
which is modified in form, sometimes into a woody fibre, sometimes into
a duct or spiral vessel, sometimes into a pollen grain, or an ovule.
Traced back to its earliest state, the nettle arises as the man does, in
a particle of nucleated protoplasm. And in the lowest plants, as in the
lowest animals, a single mass of such protoplasm may constitute the
whole plant, or the protoplasm may exist without a nucleus. Under these
circumstances it may well be asked, how is one mass of non-nucleated
protoplasm to be distinguished from another? why call one “plant” and
the other “animal?” The only reply is that, so far as form is concerned,
plants and animals are not separable, and that, in many cases, it is a
mere matter of convention whether we call a given organism an animal or
a plant.

There is a living body called _Æthalium septicum_, which appears upon
decaying vegetable substances, and in one of its forms, is common upon
the surface of tan pits. In this condition it is, to all intents and
purposes, a fungus, and formerly was always regarded as such; but the
remarkable investigations of De Bary have shown that, in another
condition, the _Æthalium_ is an actively locomotive creature, and takes
in solid matters, upon which, apparently, it feeds, thus exhibiting the
most characteristic feature of animality. Is this a plant, or is it an
animal? Is it both, or is it neither? Some decide in favor of the last
supposition, and establish an intermediate kingdom, a sort of biological
No Man’s Land for all these questionable forms. But, as it is admittedly
impossible to draw any distinct boundary line between this no man’s land
and the vegetable world on the one hand, or the animal, on the other, it
appears to me that this proceeding merely doubles the difficulty which,
before, was single. Protoplasm, simple or nucleated, is the formal basis
of all life. It is the clay of the potter; which, bake it and paint it
as he will, remains clay, separated by artifice, and not by nature, from
the commonest brick or sun-dried clod. Thus it becomes clear that all
living powers are cognate, and that all living forms are fundamentally
of one character.

The researches of the chemist have revealed a no less striking
uniformity of material composition in living matter. In perfect
strictness, it is true that chemical investigation can tell us little or
nothing, directly, of the composition of living matter, inasmuch as such
matter must needs die in the act of analysis, and upon this very obvious
ground, objections, which I confess seem to me to be somewhat frivolous,
have been raised to the drawing of any conclusions whatever respecting
the composition of actually living matter from that of the dead matter
of life, which alone is accessible to us. But objectors of this class do
not seem to reflect that it is also, in strictness, true that we know
nothing about the composition of any body whatever, as it is. The
statement that a crystal of calc-spar consists of carbonate of lime, is
quite true, if we only mean that, by appropriate processes, it may be
resolved into carbonic acid and quicklime. If you pass the same carbonic
acid over the very quicklime thus obtained, you will obtain carbonate of
lime again; but it will not be calc-spar, nor anything like it. Can it,
therefore, be said that chemical analysis teaches nothing about the
chemical composition of calc-spar? Such a statement would be absurd; but
it is hardly more so than the talk one occasionally hears about the
uselessness of applying the results of chemical analysis to the living
bodies which have yielded them. One fact, at any rate, is out of reach
of such refinements, and this is, that all the forms of protoplasm which
have yet been examined contain the four elements, carbon, hydrogen,
oxygen, and nitrogen, in very complex union, and that they behave
similarly towards several reagents. To this complex combination, the
nature of which has never been determined with exactness, the name of
Protein has been applied. And if we use this term with such caution as
may properly arise out of our comparative ignorance of the things for
which it stands, it may be truly said, that all protoplasm is
proteinaceous; or, as the white, or albumen, of an egg is one of the
commonest examples of a nearly pure protein matter, we may say that all
living matter is more or less albuminoid. Perhaps it would not yet be
safe to say that all forms of protoplasm are affected by the direct
action of electric shocks; and yet the number of cases in which the
contraction of protoplasm is shown to be affected by this agency
increases, every day. Nor can it be affirmed with perfect confidence
that all forms of protoplasm are liable to undergo that peculiar
coagulation at the temperature of 40 degrees—50 degrees centigrade,
which has been called “heat-stiffening,” though Kühne’s beautiful
researches have proved this occurrence to take place in so many and such
diverse living beings, that it is hardly rash to expect that the law
holds good for all. Enough has, perhaps, been said to prove the
existence of a general uniformity in the character of the protoplasm, or
physical basis of life, in whatever group of living beings it may be
studied. But it will be understood that this general uniformity by no
means excludes any amount of special modifications of the fundamental
substance. The mineral, carbonate of lime, assumes an immense diversity
of characters, though no one doubts that under all these Protean changes
it is one and the same thing.

And now, what is the ultimate fate, and what the origin of the matter of
life? Is it, as some of the older naturalists supposed, diffused
throughout the universe in molecules, which are indestructible and
unchangeable in themselves; but, in endless transmigration, unite in
innumerable permutations, into the diversified forms of life we know?
Or, is the matter of life composed of ordinary matter, differing from it
only in the manner in which its atoms are aggregated? Is it built up of
ordinary matter, and again resolved into ordinary matter when its work
is done? Modern science does not hesitate a moment between these
alternatives. Physiology writes over the portals of life,

                     “Debemur morti nos nostraque,”

with a profounder meaning than the Roman poet attached to that
melancholy line. Under whatever disguise it takes refuge, whether fungus
or oak, worm or man, the living protoplasm not only ultimately dies and
is resolved into its mineral and lifeless constituents, but is always
dying, and, strange as the paradox may sound, could not live unless it
died. In the wonderful story of the “Peau de Chagrin,” the hero becomes
possessed of a magical wild ass’s skin, which yields him the means of
gratifying all his wishes. But its surface represents the duration of
the proprietor’s life; and for every satisfied desire the skin shrinks
in proportion to the intensity of fruition, until at length life and the
last handbreadth of the “Peau de Chagrin,” disappear with the
gratification of a last wish. Balzac’s studies had led him over a wide
range of thought and speculation, and his shadowing forth of
physiological truth in this strange story may have been intentional. At
any rate, the matter of life is a veritable “Peau de Chagrin,” and for
every vital act it is somewhat the smaller. All work implies waste, and
the work of life results, directly or indirectly, in the waste of
protoplasm. Every word uttered by a speaker costs him some physical
loss; and, in the strictest sense, he burns that others may have
light—so much eloquence, so much of his body resolved into carbonic
acid, water and urea. It is clear that this process of expenditure
cannot go on forever. But, happily, the protoplasmic _peau de chagrin_
differs from Balzac’s in its capacity of being repaired, and brought
back to its full size, after every exertion. For example, this present
lecture, whatever its intellectual worth to you, has a certain physical
value to me, which is, conceivably, expressible by the number of grains
of protoplasm and other bodily substance wasted in maintaining my vital
processes during its delivery. My _peau de chagrin_ will be distinctly
smaller at the end of the discourse than it was at the beginning.
By-and-by, I shall probably have recourse to the substance commonly
called mutton, for the purpose of stretching it back to its original
size. Now this mutton was once the living protoplasm, more or less
modified, of another animal—a sheep. As I shall eat it, it is the same
matter altered, not only by death, but by exposure to sundry artificial
operations in the process of cooking. But these changes, whatever be
their extent, have not rendered it incompetent to resume its old
functions as matter of life. A singular inward laboratory, which I
possess, will dissolve a certain portion of the modified protoplasm, the
solution so formed will pass into my veins; and the subtle influences to
which it will then be subjected will convert the dead protoplasm into
living protoplasm, and transubstantiate sheep into man. Nor is this all.
If digestion were a thing to be trifled with, I might sup upon lobster,
and the matter of life of the crustacean would undergo the same
wonderful metamorphosis into humanity. And were I to return to my own
place by sea, and undergo shipwreck, the crustacea might, and probably
would, return the compliment, and demonstrate our common nature by
turning my protoplasm into living lobster. Or, if nothing better were to
be had, I might supply my wants with mere bread, and I should find the
protoplasm of the wheat-plant to be convertible into man, with no more
trouble than that of the sheep, and with far less, I fancy, than that of
the lobster. Hence it appears to be a matter of no great moment what
animal, or what plant, I lay under contribution for protoplasm, and the
fact speaks volumes for the general identity of that substance in all
living beings. I share this catholicity of assimilation with other
animals, all of which, so far as we know, could thrive equally well on
the protoplasm of any of their fellows, or of any plant; but here the
assimilative powers of the animal world cease.

A solution of smelling-salts in water with an infinitesimal proportion
of some other saline matters, contains all the elementary bodies which
enter into the composition of protoplasm; but, as I need hardly say, a
hogshead of that fluid would not keep a hungry man from starving, nor
would it save any animal whatever from a like fate. An animal cannot
make protoplasm, but must take it ready-made from some other animal, or
some plant—the animal’s highest feat of constructive chemistry being to
convert dead protoplasm into that living matter of life which is
appropriate to itself. Therefore, in seeking for the origin of
protoplasm, we must eventually turn to the vegetable world. The fluid
containing carbonic acid, water, and ammonia, which offers such a
barmecide feast to the animal, is a table richly spread to multitudes of
plants; and with a due supply of only such materials, many a plant will
not only maintain itself in vigor, but grow and multiply until it has
increased a million-fold, or a million million-fold, the quantity of
protoplasm which it originally possessed; in this way building up the
matter of life, to an indefinite extent, from the common matter of the
universe. Thus the animal can only raise the complex substance of dead
protoplasm to the higher power, as one may say, of living protoplasm;
while the plant can raise the less complex substances—carbonic acid,
water, and ammonia—to the same stage of living protoplasm, if not to the
same level. But the plant also has its limitations. Some of the fungi,
for example, appear to need higher compounds to start with, and no known
plant can live upon the uncompounded elements of protoplasm. A plant
supplied with pure carbon, hydrogen, oxygen, and nitrogen, phosphorus,
sulphur, and the like, would as infallibly die as the animal in his bath
of smelling-salts, though it would be surrounded by all the constituents
of protoplasm. Nor, indeed, need the process of simplification of
vegetable food be carried so far as this, in order to arrive at the
limit of the plant’s thaumaturgy.

Let water, carbonic acid, and all the other needful constituents, be
supplied without ammonia, and an ordinary plant will still be unable to
manufacture protoplasm. Thus the matter of life, so far as we know it
(and we have no right to speculate on any other) breaks up in
consequence of that continual death which is the condition of its
manifesting vitality, into carbonic acid, water, and ammonia, which
certainly possess no properties but those of ordinary matter; and out of
these same forms of ordinary matter and from none which are simpler, the
vegetable world builds up all the protoplasm which keeps the animal
world agoing. Plants are the accumulators of the power which animals
distribute and disperse.

But it will be observed, that the existence of the matter of life
depends on the preëxistence of certain compounds, namely, carbonic acid,
water, and ammonia. Withdraw any one of these three from the world and
all vital phenomena come to an end. They are related to the protoplasm
of the plant, as the protoplasm of the plant is to that of the animal.
Carbon, hydrogen, oxygen, and nitrogen are all lifeless bodies. Of
these, carbon and oxygen unite in certain proportion and under certain
conditions, to give rise to carbonic acid; hydrogen and oxygen produce
water; nitrogen and hydrogen give rise to ammonia. These new compounds,
like the elementary bodies of which they are composed, are lifeless. But
when they are brought together, under certain conditions they give rise
to the still more complex body, protoplasm, and this protoplasm exhibits
the phenomena of life. I see no break in this series of steps in
molecular complication, and I am unable to understand why the language
which is applicable to any one term of the series may not be used to any
of the others. We think fit to call different kinds of matter carbon,
oxygen, hydrogen, and nitrogen, and to speak of the various powers and
activities of these substances as the properties of the matter of which
they are composed. When hydrogen and oxygen are mixed in a certain
proportion, and the electric spark is passed through them, they
disappear and a quantity of water, equal in weight to the sum of their
weights, appears in their place. There is not the slightest parity
between the passive and active powers of the water and those of the
oxygen and hydrogen which have given rise to it. At 32 degrees
Fahrenheit, and far below that temperature, oxygen and hydrogen are
elastic gaseous bodies, whose particles tend to rush away from one
another with great force. Water, at the same temperature, is a strong
though brittle solid, whose particles tend to cohere into definite
geometrical shapes, and sometimes build up frosty imitations of the most
complex forms of vegetable foliage. Nevertheless we call these, and many
other strange phenomena, the properties of the water, and we do not
hesitate to believe that, in some way or another, they result from the
properties of the component elements of the water. We do not assume that
a something called “aquosity” entered into and took possession of the
oxide of hydrogen as soon as it was formed, and then guided the aqueous
particles to their places in the facets of the crystal, or amongst the
leaflets of the hoar-frost. On the contrary, we live in the hope and in
the faith that, by the advance of molecular physics, we shall by-and-by
be able to see our way as clearly from the constituents of water to the
properties of water, as we are now able to deduce the operations of a
watch from the form of its parts and the manner in which they are put
together. Is the case in any way changed when carbonic acid, water and
ammonia disappear, and in their place, under the influence of
preëxisting living protoplasm, an equivalent weight of the matter of
life makes its appearance? It is true that there is no sort of parity
between the properties of the components and the properties of the
resultant, but neither was there in the case of the water. It is also
true that what I have spoken of as the influence of preëxisting living
matter is something quite unintelligible; but does any body quite
comprehend the _modus operandi_ of an electric spark, which traverses a
mixture of oxygen and hydrogen? What justification is there, then, for
the assumption of the existence in the living matter of a something
which has no representative or correlative in the not living matter
which gave rise to it? What better philosophical status has “vitality”
than “aquosity?” And why should “vitality” hope for a better fate than
the other “itys” which have disappeared since Martinus Scriblerus
accounted for the operation of the meat-jack by its inherent “meat
roasting quality,” and scorned the “materialism” of those who explained
the turning of the spit by a certain mechanism worked by the draught of
the chimney? If scientific language is to possess a definite and
constant signification whenever it is employed, it seems to me that we
are logically bound to apply to the protoplasm, or physical basis of
life, the same conceptions as those which are held to be legitimate
elsewhere. If the phenomena exhibited by water are its properties, so
are those presented by protoplasm, living or dead, its properties. If
the properties of water may be properly said to result from the nature
and disposition of its component molecules, I can find no intelligible
ground for refusing to say that the properties of protoplasm result from
the nature and disposition of its molecules. But I bid you beware that,
in accepting these conclusions, you are placing your feet on the first
rung of a ladder which, in most people’s estimation, is the reverse of
Jacob’s, and leads to the antipodes of heaven. It may seem a small thing
to admit that the dull vital actions of a fungus, or a foraminifer, are
the properties of their protoplasm, and are the direct results of the
nature of the matter of which they are composed.

But if, as I have endeavored to prove to you, their protoplasm is
essentially identical with, and most readily converted into, that of any
animal, I can discover no logical halting place between the admission
that such is the case, and the further concession that all vital action
may, with equal propriety, be said to be the result of the molecular
forces of the protoplasm which displays it. And if so, it must be true,
in the same sense and to the same extent, that the thoughts to which I
am now giving utterance, and your thoughts regarding them, are the
expression of molecular changes in that matter of life which is the
source of our other vital phenomena. Past experience leads me to be
tolerably certain that, when the propositions I have just placed before
you are accessible to public comment and criticism, they will be
condemned by many zealous persons, and perhaps by some few of the wise
and thoughtful. I should not wonder if “gross and brutal materialism”
were the mildest phrase applied to them in certain quarters. And most
undoubtedly the terms of the propositions are distinctly materialistic.
Nevertheless, two things are certain: the one, that I hold the
statements to be substantially true; the other, that I, individually, am
no materialist, but, on the contrary, believe materialism to involve
grave philosophical error.

This union of materialistic terminology with the repudiation of
materialistic philosophy I share with some of the most thoughtful men
with whom I am acquainted. And, when I first undertook to deliver the
present discourse, it appeared to me to be a fitting opportunity to
explain how such an union is not only consistent with, but necessitated
by sound logic. I purposed to lead you through the territory of vital
phenomena to the materialistic slough in which you find yourselves now
plunged, and then to point out to you the sole path by which, in my
judgment, extrication is possible. An occurrence, of which I was unaware
until my arrival here last night, renders this line of argument
singularly opportune. I found in your papers the eloquent address “On
the Limits of Philosophical Inquiry,” which a distinguished prelate of
the English Church delivered before the members of the Philosophical
Institution on the previous day. My argument, also, turns upon this very
point of limits of philosophical inquiry; and I cannot bring out my own
views better than by contrasting them with those so plainly, and, in the
main, fairly stated by the Archbishop of York. But I may be permitted to
make a preliminary comment upon an occurrence that greatly astonished
me. Applying the name of “the New Philosophy” to that estimate of the
limits of philosophical inquiry which I, in common with many other men
of science, hold to be just, the Archbishop opens his address by
identifying this “new philosophy” with the positive philosophy of M.
Comte (of whom he speaks as its “founder”); and then proceeds to attack
that philosopher and his doctrine vigorously. Now, so far as I am
concerned, the most Reverend prelate might dialectically hew M. Comte in
pieces, as a modern Agag, and I should not attempt to stay his hand. In
so far as my study of what specially characterizes the Positive
Philosophy has led me, I find therein little or nothing of any
scientific value, and a great deal which is as thoroughly antagonistic
to the very essence of science as anything in ultramontane Catholicism.
In fact, M. Comte’s philosophy in practice might be compendiously
described as Catholicism _minus_ Christianity. But what has Comptism to
do with the “New Philosophy,” as the Archbishop defines it in the
following passage?

“Let me briefly remind you of the leading principles of this new
philosophy.

“All knowledge is experience of facts acquired by the senses. The
traditions of older philosophies have obscured our experience by mixing
with it much that the senses cannot observe, and until these additions
are discarded our knowledge is impure. Thus, metaphysics tells us that
one fact which we observe is a cause, and another is the effect of that
cause; but upon a rigid analysis we find that our senses observe nothing
of cause or effect; they observe, first, that one fact succeeds another,
and, after some opportunity, that this fact has never failed to
follow—that for cause and effect we should substitute invariable
succession. An older philosophy teaches us to define an object by
distinguishing its essential from its accidental qualities; but
experience knows nothing of essential and accidental; she sees only that
certain marks attach to an object, and, after many observations, that
some of them attach invariably, whilst others may at times be absent. *
* * * * As all knowledge is relative, the notion of anything being
necessary must be banished with other traditions.”

There is much here that expresses the spirit of the “New Philosophy,” if
by that term be meant the spirit of modern science; but I cannot but
marvel that the assembled wisdom and learning of Edinburgh should have
uttered no sign of dissent, when Comte was declared to be the founder of
these doctrines. No one will accuse Scotchmen of habitually forgetting
their great countrymen; but it was enough to make David Hume turn in his
grave, that here, almost within ear-shot of his house, an instructed
audience should have listened, without a murmur, while his most
characteristic doctrines were attributed to a French writer of fifty
years later date, in whose dreary and verbose pages we miss alike the
vigor of thought and the exquisite clearness of the style of the man
whom I make bold to term the most acute thinker of the eighteenth
century—even though that century produced Kant. But I did not come to
Scotland to vindicate the honor of one of the greatest men she has ever
produced. My business is to point out to you that the only way of escape
out of the crass materialism in which we just now landed is the adoption
and strict working out of the very principles which the Archbishop holds
up to reprobation.

Let us suppose that knowledge is absolute, and not relative, and
therefore, that our conception of matter represents that which it really
is. Let us suppose, further, that we do know more of cause and effect
than a certain definite order of succession among facts, and that we
have a knowledge of the necessity of that succession—and hence, of
necessary laws—and I, for my part, do not see what escape there is from
utter materialism and necessitarianism. For it is obvious that our
knowledge of what we call the material world is, to begin with, at least
as certain and definite as that of the spiritual world, and that our
acquaintance with the law is of as old a date as our knowledge of
spontaneity.

Further, I take it to be demonstrable that it is utterly impossible to
prove that anything whatever may not be the effect of a material and
necessary cause, and that human logic is equally incompetent to prove
that any act is really spontaneous. A really spontaneous act is one
which, by the assumption, has no cause; and the attempt to prove such a
negative as this is, on the face of the matter, absurd. And while it is
thus a philosophical impossibility to demonstrate that any given
phenomenon is not the effect of a material cause, any one who is
acquainted with the history of science will admit, that its progress
has, in all ages, meant, and now more than ever means, the extension of
the province of what we call matter and causation, and the concomitant
gradual banishment from all regions of human thought of what we call
spirit and spontaneity.

I have endeavored, in the first part of this discourse, to give you a
conception of the direction towards which modern physiology is tending;
and I ask you, what is the difference between the conception of life as
the product of a certain disposition of material molecules, and the old
notion of an Archæus governing and directing blind matter within each
living body, except this—that here, as elsewhere, matter and law have
devoured spirit and spontaneity? And as surely as every future grows out
of past and present, so will the physiology of the future gradually
extend the realm of matter and law until it is coëxtensive with
knowledge, with feeling, and with action. The consciousness of this
great truth weighs like a nightmare, I believe, upon many of the best
minds of these days. They watch what they conceive to be the progress of
materialism, in such fear and powerless anger as a savage feels, when,
during an eclipse, the great shadow creeps over the face of the sun. The
advancing tide of matter threatens to drown their souls; the tightening
grasp of law impedes their freedom; they are alarmed lest man’s moral
nature be debased by the increase of his wisdom.

If the “New Philosophy” be worthy of the reprobation with which it is
visited, I confess their fears seem to me to be well founded. While, on
the contrary, could David Hume be consulted, I think he would smile at
their perplexities, and chide them for doing even as the heathen, and
falling down in terror before the hideous idols their own hands have
raised. For, after all, what do we know of this terrible “matter,”
except as a name for the unknown and hypothetical cause of states of our
own consciousness? And what do we know of that “spirit” over whose
threatened extinction by matter a great lamentation is arising, like
that which was heard at the death of Pan, except that it is also a name
for an unknown and hypothetical cause, or condition, of states of
consciousness? In other words, matter and spirit are but names for the
imaginary substrata of groups of natural phenomena. And what is the dire
necessity and “iron” law under which men groan? Truly, most gratuitously
invented bugbears. I suppose if there be an “iron” law, it is that of
gravitation; and if there be a physical necessity, it is that a stone,
unsupported, must fall to the ground. But what is all we really know and
can know about the latter phenomenon? Simply, that, in all human
experience, stones have fallen to the ground under these conditions;
that we have not the smallest reason for believing that any stone so
circumstanced will not fall to the ground, and that we have, on the
contrary, every reason to believe that it will so fall. It is very
convenient to indicate that all the conditions of belief have been
fulfilled in this case, by calling the statement that unsupported stones
will fall to the ground, “a law of nature.” But when, as commonly
happens, we change will into must, we introduce an idea of necessity
which most assuredly does not lie in the observed facts, and has no
warranty that I can discover elsewhere. For my part, I utterly repudiate
and anathematize the intruder. Fact, I know; and Law I know; but what is
this Necessity, save an empty shadow of my own mind’s throwing? But, if
it is certain that we can have no knowledge of the nature of either
matter or spirit, and that the notion of necessity is something
illegitimately thrust into the perfectly legitimate conception of law,
the materialistic position that there is nothing in the world but
matter, force, and necessity, is as utterly devoid of justification as
the most baseless of theological dogmas.

The fundamental doctrines of materialism, like those of spiritualism,
and most other “isms,” lie outside “the limits of philosophical
inquiry,” and David Hume’s great service to humanity is his irrefragable
demonstration of what these limits are. Hume called himself a sceptic,
and therefore others cannot be blamed if they apply the same title to
him; but that does not alter the fact that the name, with its existing
implications, does him gross injustice. If a man asks me what the
politics of the inhabitants of the moon are, and I reply that I do not
know; that neither I, nor any one else have any means of knowing; and
that, under these circumstances I decline to trouble myself about the
subject at all, I do not think he has any right to call me a sceptic. On
the contrary, in replying thus, I conceive that I am simply honest and
truthful, and show a proper regard for the economy of time. So Hume’s
strong and subtle intellect takes up a great many problems about which
we are naturally curious, and shows us that they are essentially
questions of lunar politics, in their essence incapable of being
answered, and therefore not worth the attention of men who have work to
do in the world. And thus ends one of his essays:

    “If we take in hand any volume of Divinity, or school
    metaphysics, for instance, let us ask, _Does it contain any
    abstract reasoning concerning quantity or number?_ No. _Does it
    contain any experimental reasoning concerning matter of fact and
    existence?_ No. Commit it then to the flames; for it can contain
    nothing but sophistry and illusion.”

Permit me to enforce this most wise advice. Why trouble ourselves about
matters of which, however important they may be, we do know nothing, and
can know nothing? We live in a world which is full of misery and
ignorance, and the plain duty of each and all of us is to try to make
the little corner he can influence somewhat less miserable and somewhat
less ignorant than it was before he entered it. To do this effectually
it is necessary to be fully possessed of only two beliefs: the first,
that the order of nature is ascertainable by our faculties to an extent
which is practically unlimited; the second, that our volition counts for
something as a condition of the course of events. Each of these beliefs
can be verified experimentally, as often as we like to try. Each,
therefore, stands upon the strongest foundation upon which any belief
can rest; and forms one of our highest truths.

If we find that the ascertainment of the order of nature is facilitated
by using one terminology, or one set of symbols, rather than another, it
is our clear duty to use the former, and no harm can accrue so long as
we bear in mind that we are dealing merely with terms and symbols. In
itself it is of little moment whether we express the phenomena of matter
in terms of spirit, or the phenomena of spirit in terms of matter;
matter may be regarded as a form of thought, thought may be regarded as
a property of matter—each statement has a certain relative truth. But
with a view to the progress of science, the materialistic terminology is
in every way to be preferred. For it connects thought with the other
phenomena of the universe, and suggests inquiry into the nature of those
physical conditions or concomitants of thought, which are more or less
accessible to us, and a knowledge of which may, in future, help us to
exercise the same kind of control over the world of thought as we
already possess in respect of the material world; whereas, the
alternative, or spiritualistic, terminology is utterly barren, and leads
to nothing but obscurity and confusion of ideas. Thus there can be
little doubt that the further science advances, the more extensively and
consistently will all the phenomena of nature be represented by
materialistic formulæ and symbols. But the man of science, who,
forgetting the limits of philosophical inquiry, slides from these
formulæ and symbols into what is commonly understood by materialism,
seems to me to place himself on a level with the mathematician, who
should mistake the _x’s_ and _y’s_, with which he works his problems,
for real entities—and with this further disadvantage as compared with
the mathematician, that the blunders of the latter are of no practical
consequence, while the errors of systematic materialism may paralyze the
energies and destroy the beauty of a life.


------------------------------------------------------------------------




            _THE CORRELATION OF VITAL AND PHYSICAL FORCES._




------------------------------------------------------------------------




                            THE CORRELATION

                                   OF

                       VITAL AND PHYSICAL FORCES.


In the Syracusan Poecile, says Alexander von Humboldt in his beautiful
little allegory of the Rhodian Genius, hung a painting, which, for full
a century, had continued to attract the attention of every visitor. In
the foreground of this picture a numerous company of youths and maidens
of earthly and sensuous appearance gazed fixedly upon a haloed Genius
who hovered in their midst. A butterfly rested upon his shoulder, and he
held in his hand a flaming torch. His every lineament bespoke a
celestial origin. The attempts to solve the enigma of this
painting—whose origin even was unknown—though numerous, were all in
vain, when one day a ship arriving from Rhodes, laden with works of art,
brought another picture, at once recognized as its companion. As before,
the Genius stood in the center, but the butterfly had disappeared, and
the torch was reversed and extinguished. The youths and maidens were no
longer sad and submissive, their mutual embraces announcing their entire
emancipation from restraint. Still unable to solve the riddle, Dionysius
sent the pictures to the Pythagorean sage, Epicharmus. After gazing upon
them long and earnestly, he said: Sixty years long have I pondered on
the internal springs of nature, and on the differences inherent in
matter; but it is only this day that the Rhodian Genius has taught me to
see clearly that which before I had only conjectured. In inanimate
nature, everything seeks its like. Everything, as soon as formed,
hastens to enter into new combinations, and nought save the disjoining
art of man can present in a separate state ingredients which ye would
vainly seek in the interior of the earth or in the moving oceans of air
and water. Different, however, is the blending of the same substances in
animal and vegetable bodies. Here vital force imperatively asserts its
rights, and heedless of the affinity and antagonism of the atoms, unites
substances which in inanimate nature ever flee from each other, and
separates that which is incessantly striving to unite. Recognize,
therefore, in the Rhodian Genius, in the expression of his youthful
vigor, in the butterfly on his shoulder, in the commanding glance of his
eye, the symbol of vital force as it animates every germ of organic
creation. The earthly elements at his feet are striving to gratify their
own desires and to mingle with one another. Imperiously the Genius
threatens them with upraised and high-flaming torch, and compels them
regardless of their ancient rights, to obey his laws. Look now on the
new work of art; turn from life to death. The butterfly has soared
upward, the extinguished torch is reversed, and the head of the youth is
drooping; the spirit has fled to other spheres, and the vital force is
extinct. Now the youths and maidens join their hands in joyous accord.
Earthly matter again resumes its rights. Released from all bonds, they
impetuously follow their natural instincts, and the day of his death is
to them a day of nuptials.[1]

The view here put by Humboldt into the mouth of Epicharmus may be taken
as a fair representation of the current opinion of all ages concerning
vital force. To-day, as truly as seventy-five years ago when Humboldt
wrote, the mysterious and awful phenomena of life are commonly
attributed to some controlling agent residing in the organism—to some
independent presiding deity, holding it in absolute subjection. Such a
notion it was which prompted Heraclitus to talk of a universal fire, Van
Helmont to propose his Archæus, Hofmann his vital fluid, Hunter his
_materia vitæ diffusa_, and Humboldt his vital force.[2] All these names
assume the existence of a material or immaterial something, more or less
separable from the material body, and more or less identical with the
mind or soul, which is the cause of the phenomena of living beings. But
as science moved irresistibly onward, and it became evident that the
forces of inorganic nature were neither deities nor imponderable fluids,
separable from matter, but were simple affections of it, analogy
demanded a like concession in behalf of vital force.[3] From the notion
that the effects of heat were due to an imponderable fluid called
caloric, discovery passed to the conviction that heat was but a motion
of material particles, and hence inseparable from matter. To a like
assumption concerning vitality it was now but a step. The more advanced
thinkers in science of to-day, therefore, look upon the life of the
living form as inseparable from its substance, and believe that the
former is purely phenomenal, and only a manifestation of the latter.
Denying the existence of a special vital force as such, they retain the
term only to express the sum of the phenomena of living beings.

In calling your attention this evening to the Correlation of the
Physical and the Vital Forces, I have a twofold object in view. On the
one hand, I would seek to interest you in a comparatively recent
discovery of Science, and one which is destined to play a most important
part in promoting man’s welfare; and on the other I would inquire what
part our own country has had in these discoveries.

In the first place, then, let us consider what the evidences are that
vital and physical forces are correlated. Let us inquire how far
inorganic and organic forces may be considered mutually convertible, and
hence, in so far, mutually identical. This may best be done by
considering, first, what is to be understood by correlation: and second,
how far are the physical forces themselves correlated to each other.

At the outset of our discussion, we are met by an unfortunate ambiguity
of language. The word Force, as commonly used, has three distinct
meanings; in the first place, it is used to express the cause of motion,
as when we speak of the force of gunpowder; it is also used to indicate
motion itself, as when we refer to the force of a moving cannon-ball;
and lastly it is employed to express the effect of motion, as when we
speak of the blow which the moving body gives.[4] Because of this
confusion, it has been found convenient to adopt Rankine’s
suggestion,[5] and to substitute the word ‘energy’ therefor. And
precisely as all force upon the earth’s surface—using the term force in
its widest sense—may be divided into attraction and motion, so all
energy is divided into potential and actual energy, synonymous with
those terms. It is the chemical attraction of the atoms, or their
potential energy, which makes gunpowder so powerful; it is the
attraction or potential energy of gravitation which gives the power to a
raised weight. If now, the impediments be removed, the power just now
latent becomes active, attraction is converted into motion, potential
into actual energy, and the desired effect is accomplished. The energy
of gunpowder or of a raised weight is potential, is capable of acting;
that of exploding gunpowder or of a falling weight is actual energy or
motion. By applying a match to the gunpowder, by cutting the string
which sustains the weight, we convert potential into actual energy. By
potential energy, therefore, is meant attraction; and by actual energy,
motion. It is in the latter sense that we shall use the word force in
this lecture; and we shall speak of the forces of heat, light,
electricity and mechanical motion, and of the attractions of
gravitation, cohesion, chemism.

From what has now been said, it is obvious that when we speak of the
forces of heat, light, electricity or motion, we mean simply the
different modes of motion called by these names. And when we say that
they are correlated to each other, we mean simply that the mode of
motion called heat, light, electricity, is convertible into any of the
others, at pleasure. Correlation therefore implies convertibility, and
mutual dependence and relationship.

Having now defined the use of the term force, and shown that forces are
correlated which are convertible and mutually dependent, we go on to
study the evidences of such correlation among the motions of inorganic
nature usually called physical forces; and to ask what proof science can
furnish us that mechanical motion, heat, light, and electricity are thus
mutually convertible. As we have already hinted, the time was when these
forces were believed to be various kinds of imponderable matter, and
chemists and physicists talked of the union of iron with caloric as they
talked of its union with sulphur, regarding the caloric as much a
distinct and inconvertible entity as the iron and sulphur themselves.
Gradually, however, the idea of the indestructibility of matter extended
itself to force. And as it was believed that no material particle could
ever be lost, so, it was argued, no portion of the force existing in
nature can disappear. Hence arose the idea of the indestructibility of
force. But, of course, it was quite impossible to stop here. If force
cannot be lost, the question at once arises, what becomes of it when it
passes beyond our recognition? This question led to experiment, and out
of experiment came the great fact of force-correlation; a fact which
distinguished authority has pronounced the most important discovery of
the present century.[6] These experiments distinctly proved that when
any one of these forces disappeared, another took its place; that when
motion was arrested, for example, heat, light or electricity was
developed. In short, that these forces were so intimately related or
correlated—to use the word then proposed by Mr. Grove[7]—that when one
of them vanished, it did so only to reappear in terms of another. But
one step more was necessary to complete this magnificent theory. What
can produce motion but motion itself? Into what can motion be converted,
but motion? May not these forces, thus mutually convertible, be simply
different modes of motion of the molecules of matter, precisely as
mechanical motion is a motion of its mass? Thus was born the dynamic
theory of force, first brought out in any completeness by Mr. Grove, in
1842, in a lecture on the “Progress of Physical Science,” delivered at
the London Institution. In that lecture he said: “Light, heat,
electricity, magnetism, motion, are all convertible material affections.
Assuming either as the cause, one of the others will be the effect. Thus
heat may be said to produce electricity, electricity to produce heat;
magnetism to produce electricity, electricity magnetism; and so of the
rest.”[8]

A few simple experiments will help us to fix in our minds the great fact
of the convertibility of force. Starting with actual visible motion,
correlation requires that when it disappears as motion, it should
reappear as heat, light, or electricity. If the moving body be elastic
like this rubber ball, then its motion is not destroyed when it strikes,
but is only changed in direction. But if it be non-elastic, like this
ball of lead, then it does not rebound; its motion is converted into
heat. The motion of this sledge-hammer, for example, which if received
upon this anvil would be simply changed in direction, if allowed to fall
upon this bar of lead, is converted into heat; the evidence of which is
that a piece of phosphorus placed upon the lead is at once inflamed. So
too, if motion be arrested by the cushion of air in this cylinder, the
heat evolved fires the tinder carried in the plunger. But it is not
necessary that the arrest of motion should be sudden; it may be gradual,
as in the case of friction. If this cylinder containing water or alcohol
be caused to revolve rapidly between the two sides of this wooden
rubber, the heat due to the arrested motion will raise the temperature
of the liquid to the boiling point, and the cork will be expelled. But
motion may also be converted into electricity. Indeed electricity is
always the result of friction between heterogeneous particles.[9] When
this piece of hard rubber, for example, is rubbed with the fur of a cat,
it is at once electrified; and now if it be caused to communicate a
portion of its charge to this glass plate, to which at the same time we
add the mechanical motion of rotation, the strong sparks produced give
evidence of the conversion.

So, too, taking heat as the initial force, motion, light, electricity
may be produced. In every steam-engine the steam which leaves the
cylinder is cooler than that which entered it, and cooler by exactly the
amount of work done. The motion of the piston’s mass is precisely that
lost by the steam molecules which batter against it. The conversion of
heat into electricity, too, is also easily effected. When the junction
of two metals is heated, electricity is developed. If the two metals be
bismuth and antimony, as represented in this diagram, the currents flow
as indicated by the arrows; and by multiplying the number of pairs, the
effect may be proportionately increased. Such an arrangement, called a
thermo-electric battery, we have here; and by it the heat of a single
gas-burner may be made to move, when converted, this little electric
bell-engine. Moreover, heat and light have the very closest analogy;
exalt the rapidity with which the molecules move and light appears, the
difference being only one of intensity.

Again, if electricity be our starting point, we may accomplish its
conversion into the other forces. Heat results whenever its passage is
interrupted or resisted; a wire of the poorly conducting metal platinum
becoming even red-hot by the converted electricity. To produce light, of
course, we need only to intensify this action; the brightest artificial
light known, results from a direct conversion of electricity.

Enough has now been said to establish our point. What is to be
particularly observed of these pieces of apparatus is that they are
machines especially designed for the conversion of some one force into
another. And we expect of them only that conversion. We pass on to
consider for a moment the quantitative relations of this mutual
convertibility. We notice, in the first place, that in all cases save
one, the conversion is not perfect, a part of the force used not being
utilized, on the one hand, and on the other, other forces making their
appearance simultaneously. While, for example, the conversion of motion
into heat is quite complete, the inverse conversion is not at all so.
And on the other hand, when motion is converted into electricity, a part
of it appears as heat. This simultaneous production of many forces is
well illustrated by our little bell-engine, which converts the
electricity of the thermo-battery into magnetism, and this into motion,
a part of which expends itself as sound. For these reasons the question
“How much?” is one not easily answered in all cases. The best known of
these relations is that between motion and heat, which was first
established by Mr. Joule in 1849, after seven years of patient
investigation.[10] The apparatus which he used is shown in the diagram.
It consists of a cylindrical box of metal, through the cover of which
passes a shaft, carrying upon its lower end a set of paddles, immersed
in water within the box, and upon its upper portion a drum, on which are
wound two cords, which, passing in opposite directions, run over
pulleys, and are attached to known weights. The temperature of the water
within the box being carefully noted, the weights are then allowed to
fall a certain number of times, of course in their fall turning the
paddles against the friction of the liquid. At the close of the
experiment the water is found to be warmer than before. And by measuring
the amount of this rise in temperature, knowing the distance through
which the weights have fallen, it is easy to calculate the quantity of
heat which corresponds to a given amount of motion. In this way, and as
a mean of a large number of experiments, Mr. Joule found that the amount
of mass motion in a body weighing one pound, which had fallen from a
hight of 772 feet, was exactly equal to the molecular motion which must
be added to a pound of water, in order to heat it one degree Fahrenheit.
If we call the actual energy of a body weighing one pound which has
fallen one foot, a foot-pound, then we may speak of the mechanical
equivalent of heat as being 772 foot-pounds.

The significance and value of this numerical constant will appear more
clearly if we apply it to the solution of one or two simple problems.
During the recent war two immense iron guns were cast in Pittsburgh,
whose weight was nearly 112,000 pounds each, and which had a caliber of
20 inches.[11] Upon this diagram is a calculation of the effective blow
which the solid shot of such a gun, assuming its weight to be 1,000
pounds and its velocity 1,100 feet per second, would give; it is 902,797
tons![12] Now, if it were possible to convert the whole of this enormous
mechanical power into heat, to how much would it correspond? This
question may be answered by the aid of the mechanical equivalent of
heat; here is the calculation, from which we see that when 17 gallons of
ice-cold water are heated to the boiling point, as much energy is
communicated as is contained in the death-dealing missile at its highest
velocity.[13] Again, if we take the impact of a larger cannon-ball, our
earth, which is whirling through space with a velocity of 19 miles a
second, we find it to be 98,416,136,000,000,000,000,000,000,000,000
tons![14] Were this energy all converted into heat, it would equal that
produced by the combustion of 14 earths of solid coal.[15]

The conversion of heat into motion, however, as already stated, is not
as perfect. The best steam-engines economize only one-twentieth of the
heat of the fuel.[16] Hence if a steamship require 600 tons of coal to
carry her across the Atlantic, 570 tons will be expended in heating the
waters of the ocean, the heat of the remaining 30 tons only being
converted into work.

One other quantitative determination of force has also been made. Prof.
Julius Thomsen, of Copenhagen, has fixed experimentally the mechanical
equivalent of light.[17] He finds that the energy of the light of a
spermaceti candle burning 126½ grains per hour, is equal in mechanical
value to 13·1 foot-pounds per minute. The same conclusion has been
reached by Mr. Farmer, of Boston, from different data.[18]

If we pass from the actual physical energies or motions to consider for
a moment the potential energies or attractions, we find, also, an
intimate correlation. Since all energy not active in motion is potential
in attraction, it follows that in the attractions we have energy stored
up for subsequent use. The sun is thus storing up energy: every minute
it raises 2,000,000,000 tons of water to the mean hight of the clouds,
3½ miles; and the actual energy set free when this water falls is equal
to 2,757,000,000,000 horse-powers.[19] So when the oxygen and the zinc
of the ore are separated in the furnace, the actual energy of heat
becomes the potential energy of chemical attraction, which again becomes
actual in the form of electricity when the zinc is dissolved in an acid.
We see, then, that not only may any form of force or actual energy be
stored up as any form of attraction or potential energy, but that the
latter, from whatsoever source derived, may appear as heat, light,
electricity, or mechanical motion.

Having now established the fact of correlation for the physical forces,
we have next to inquire what are the evidences of the correlation of the
vital forces with them. But in the first place it must be remarked that
life is not a simple term like heat or electricity; it is a complex
term, and includes all those phenomena which a living body exhibits. In
this discussion, therefore, we shall use the term vital force to express
only the actual energy of the body, however manifested. As to the
attractions or the potential energy of the organism, nothing is more
fully settled in science than the fact that these are precisely the same
within the body as without it. Every particle of matter within the body
obeys implicitly the laws of the chemical and physical attractions. No
overpowering or supernatural agency comes in to complicate their action,
which is modified only by the action of the others. Vitality, therefore,
is the sum of the energies of a living body, both potential and actual.

Moreover, the important fact must be fully recognized that in living
beings we have to do with no new elementary forms of matter. Precisely
the same atoms which build up the inorganic fabric, compose the organic.
In the early days of chemistry, indeed, it was supposed that the
complicated molecules which life produced were beyond the reach of
simple chemical law. But as more and more complex molecules have been,
one after another, produced, chemistry has become re-assured, and now
doubts not her ability to produce them all. A few years hence, and she
will doubtless give us quinine and protagon, as she now gives us
coumarin and neurine, substances the synthesis of which was but
yesterday an impossibility.[20]

In studying the phenomena of living beings, it is important also to bear
in mind the different and at the same time the coördinate purposes
subserved by the two great kingdoms of nature. The food of the plant is
matter whose energy is all expended; it is a fallen weight. But the
plant-organism receives it, exposes it to the sun’s ray, and, in a way
yet mysterious to us, converts the actual energy of the sunlight into
potential energy within it. The fallen weight is thus raised, and energy
is stored up in substances which now are alone competent to become the
food of the animal. This food is not such because any new atoms have
been added to it; it is food because it contains within it potential
energy, which at any time may become actual as force. This food the
animal now appropriates; he brings it in contact with oxygen, and the
potential energy becomes actual; he cuts the string, the weight falls,
and what was just now only attraction, has become actual force; this
force he uses for his own purposes, and hands back the oxidized matter,
the fallen weight, to the plant to be again de-oxidized, to be again
raised. The plant then is to be regarded as a machine for converting
sunlight into potential energy; the animal, a machine for setting the
potential energy free as actual, and economizing it. The force which the
plant stores up is undeniably physical; must not the force which the
animal sets free by its conversion, be intimately correlated to it?

But approaching our question still more closely, let us, in illustration
of the vital forces of the animal economy, choose three forms of its
manifestation in which to seek for the evidences of correlation; these
shall be heat, evolved within the body; muscular energy or motion; and
lastly, nervous energy, or that form of force which, on the one hand,
stimulates a muscle to contract, and on the other, appears in forms
called mental.

The heat which is produced by the living body is obviously of the same
nature as heat from any other source; it is recognized by the same
tests, and may be applied for the same purposes. As to its origin, it is
evident that since potential energy exists in the food which enters the
body, and is there converted into force, a portion of it may become the
actual energy of heat. And since, too, the heat produced in the body is
precisely such as would be set free by the combustion of this food
outside of it, it is fair to assume that it thus originates. To this may
be added the chemical argument that while food capable of yielding heat
by combustion is taken into the body, its constituents are completely or
almost completely, oxidized before leaving it; and since oxidation
always evolves heat, the heat of the body must have its origin in the
oxidation of the food. Moreover, careful measurements have demonstrated
that the amount of heat given off by the body of a man weighing 180
pounds is about 2,500,000 units. Accurate calculations have shown, on
the other hand, that 288·4 grams of carbon and 12·56 grams of hydrogen
are available in the daily food for the production of heat. If burned
out of the body, these quantities of carbon and hydrogen would yield
2,765,134 heat units. Burned within it, as we have just seen, 2,500,000
units appear as heat; the rest in other forms of energy.[21] We
conceive, however, that no long argument is necessary to prove that
animal heat results from a conversion of energy within the body; or that
the vital force heat, is as truly correlated to the other forces as when
it has a purely physical origin.

The belief that the muscular force exerted by an animal is created by
him is by no means confined to the very earliest ages of history.
Traces of it appear to the careful observer even now, although, as Dr.
Frankland says, science has proved that “an animal can no more
generate an amount of force capable of moving a grain of sand than a
stone can fall upward or a locomotive drive a train without fuel.”[22]
In studying the characters of muscular action we notice, first, that,
as in the case of heat, the force which it develops is in no wise
different from motion in inorganic nature. In the early part of the
lecture, motion produced by the contraction of muscle, was used to
show the conversion of mass-force into molecular force. No one in this
room believes, I presume, that the result would have been at all
different, had the motion been supplied by a steam-engine or a
water-wheel. Again, food, as we have seen, is of value for the
potential energy it contains, which may become actual in the body.
Liebig, in 1842, asserted that for the production of muscular force,
the food must first be converted into muscular tissue,[23] a view
until recently accepted by physiologists.[24] It has been conclusively
shown, however, within a few years, that muscular force cannot come
from the oxidation of its own substance, since the products of this
metamorphosis are not increased in amount by muscular exertion.[25]
Indeed, reasoning from the whole amount of such products excreted, the
oxidation of the amount of muscle which they represent would furnish
scarcely one-fifth of the mechanical force of the body. But while the
products of tissue-oxidation do not increase with the increase of
muscular exertion, the amount of carbonic gas exhaled by the lungs is
increased in the exact ratio of the work done.[26] No doubt can be
entertained, therefore, that the actual energy of the muscle is simply
the converted potential energy of the carbon of the food. A muscle,
therefore, like a steam-engine, is a machine for converting the
potential energy of carbon into motion. But unlike a steam-engine, the
muscle accomplishes this conversion directly, the energy not passing
through the intermediate stage of heat. For this reason, the muscle is
the most economical producer of mechanical force known. While no
machine whatever can transform all of the energy into motion—the most
economical steam-engines utilizing only one-twentieth of the heat—the
muscle is able to convert one-fifth of the energy of the food into
work.[27] The other four-fifths must, therefore, appear as heat.
Whenever a muscle contracts, then, four times as much energy appears
as heat as is converted into motion. Direct experiments by Heidenhain
have confirmed this, by showing that an important rise of temperature
attends muscular contraction;[28] a fact, however, apparent to any one
who has ever taken active exercise. The work done by the animal body
is of two sorts, internal and external. The former includes the action
of the heart, of the respiratory muscles, and of those assisting the
digestive process. The latter refers to the useful work the body may
perform. Careful estimates place the entire work of the body at about
800 foot-tons daily; of which 450 foot-tons is internal, 350 foot-tons
external work. And since the internal work ultimately appears as heat
within the body, the actual loss of heat by the production of motion
is the equivalent of the 350 foot-tons which represents external work.
This by a simple calculation will be found to be 250,000 heat units,
almost the precise amount by which the heat yielded by the food when
burned without the body, exceeds that actually evolved by the
organism. Moreover, while the total heat given off by the body is
2,500,000 units, the amount of energy evolved as work is equal to
about 600,000 heat units; hence the amount of work done by a muscle is
as above stated, one-fifth of the actual energy derivable from the
food. One point further. The law of correlation requires that the heat
set free when a muscle in contracting does work, shall be less than
when it effects nothing; this fact, too, has been experimentally
established by Heidenhain.[29] So, again, when muscular contraction
does not result in motion, as when one tries to raise a weight too
heavy for him, the energy which would have appeared as work, takes the
form of heat: a result deducible by the law of correlation from the
steam-engine.

The last of the so-called vital forces which we are to examine, is that
produced by the nerves and nervous centers. In the nerve which
stimulates a muscle to contract, this force is undeniably motion, since
it is propagated along this nerve from one extremity to the other. In
common language, too, this idea finds currency in the comparison of this
force to electricity; the gray or cellular matter being the battery, the
white or fibrous matter the conductors. That this force is not
electricity, however, Du Bois-Reymond has demonstrated by showing that
its velocity is only 97 feet in a second, a speed equaled by the
greyhound and the race-horse.[30] In his opinion, the propagation of a
nervous impulse is a sort of successive molecular polarization, like
magnetism. But that this agent is a force, as analogous to electricity
as is magnetism, is shown not only by the fact that the transmission of
electricity along a nerve will cause the contraction of the muscle to
which it leads, but also by the more important fact that the contraction
of a muscle is excited by diminishing its normal electrical current;[31]
a result which could take place only with a stimulus closely allied to
electricity. Nerve-force, therefore, must be a transmuted potential
energy.

What, now, shall we say of that highest manifestation of animal life,
thought-power? Has the upper region called intelligence and reason, any
relations to physical force? This realm has not escaped the searching
investigation of modern science; and although in it investigations are
vastly more difficult than in any of the regions thus far considered,
yet some results of great value have been obtained, which may help us to
a solution of our problem. It is to be observed at the outset that every
external manifestation of thought-force is a muscular one, as a word
spoken or written, a gesture, or an expression of the face; and hence
this force must be intimately correlated with nerve-force. These
manifestations, reaching the mind through the avenues of sense, awaken
accordant trains of thought only when this muscular evidence is
understood. A blank sheet of paper excites no emotion; even covered with
Assyrian cuneiform characters, its alternations of black and white
awaken no response in the ordinary brain. It is only when, by a frequent
repetition of these impressions, the brain-cell has been educated, that
these before meaningless characters awaken thought. Is thought, then,
simply a cell action which may or may not result in muscular
expression—an action which originates new combinations of truth only,
precisely as a calculating machine evolves new combinations of figures?
Whatever we define thought to be, this fact appears certain, that it is
capable of external manifestation by conversion into the actual energy
of motion, and only by this conversion. But here the question arises,
Can it be manifested inwardly without such a transformation of energy?
Or is the evolution of thought entirely independent of the matter of the
brain? Experiments, ingenious and reliable, have answered this question.
The importance of the results will, I trust, warrant me in examining the
methods employed in these experiments somewhat in detail. Inasmuch as
our methods for measuring minute amounts of electricity are very
perfect, and the methods for the conversion of heat into electricity are
equally delicate, it has been found that smaller differences of
temperature may be recognized by converting the heat into electricity,
than can be detected thermometrically. The apparatus, first used by
Melloni in 1832,[32] is very simple, consisting first, of a pair of
metallic bars like those described in the early part of the lecture, for
effecting the conversion of the heat; and second, of a delicate
galvanometer, for measuring the electricity produced. In the experiments
in question one of the bars used was made of bismuth, the other of an
alloy of antimony and zinc.[33] Preliminary trials having shown that any
change of temperature within the skull was soonest manifested externally
in that depression which exists just above the occipital protuberance, a
pair of these little bars was fastened to the head at this point; and to
neutralize the results of a general rise of temperature over the whole
body, a second pair, reversed in direction, was attached to the leg or
arm, so that if a like increase of heat came to both, the electricity
developed by one would be neutralized by the other, and no effect be
produced upon the needle unless only one was affected. By long practice
it was ascertained that a state of mental torpor could be induced,
lasting for hours, in which the needle remained stationary. But let a
person knock on the door outside the room, or speak a single word, even
though the experimenter remained absolutely passive, and the reception
of the intelligence caused the needle to swing through 20 degrees.[34]
In explanation of this production of heat, the analogy of the muscle at
once suggests itself. No conversion of energy is complete; and as the
heat of muscular action represents force which has escaped conversion
into motion, so the heat evolved during the reception of an idea, is
energy which has escaped conversion into thought, from precisely the
same cause. Moreover, these experiments have shown that ideas which
affect the emotions, produce most heat in their reception; “a few
minutes’ recitation to one’s self of emotional poetry, producing more
effect than several hours of deep thought.” Hence it is evident that the
mechanism for the production of deep thought, accomplishes this
conversion of energy far more perfectly than that which produces simply
emotion. But we may take a step further in this same direction. A
muscle, precisely as the law of correlation requires, develops less heat
when doing work than when it contracts without doing it. Suppose, now,
that beside the simple reception of an idea by the brain, the thought is
expressed outwardly by some muscular sign. The conversion now takes two
directions, and in addition to the production of thought, a portion of
the energy appears as nerve and muscle-power; less, therefore, should
appear as heat, according to our law of correlation. Dr. Lombard’s
experiments have shown that the amount of heat developed by the
recitation to one’s self of emotional poetry, was in every case less
when that recitation was oral; _i.e._, had a muscular expression. These
results are in accordance with the well-known fact that emotion often
finds relief in physical demonstrations; thus diminishing the emotional
energy by converting it into muscular. Nor do these facts rest upon
physical evidence alone. Chemistry teaches that thought-force, like
muscle-force, comes from the food; and demonstrates that the force
evolved by the brain, like that produced by the muscle, comes not from
the disintegration of its own tissue, but is the converted energy of
burning carbon.[35] Can we longer doubt, then, that the brain, too, is a
machine for the conversion of energy? Can we longer refuse to believe
that even thought is, in some mysterious way, correlated to the other
natural forces? and this, even in face of the fact that it has never yet
been measured?[36]

I cannot close without saying a word concerning the part which our own
country has had in the development of these great truths. Beginning with
heat, we find that the material theory of caloric is indebted for its
overthrow more to the distinguished Count Rumford than to any other one
man. While superintending the boring of cannon at the Munich Arsenal
towards the close of the last century, he was struck by the large amount
of heat developed, and instituted a careful series of experiments to
ascertain its origin. These experiments led him to the conclusion that
“anything which any insulated body or system of bodies can continue to
furnish without limitation, cannot possibly be a material substance.”
But this man, to whom must be ascribed the discovery of the first great
law of the correlation of energy, was an American. Born in Woburn,
Mass., in 1753, he, under the name of Benjamin Thompson, taught school
afterward at Concord, N. H., then called Rumford. Unjustly suspected of
toryism during our Revolutionary war, he went abroad and distinguished
himself in the service of several of the Governments of Europe. He did
not forget his native land, though she had treated him so unfairly; when
the honor of knighthood was tendered him, he chose as his title the name
of the Yankee village where he had taught school, and was thenceforward
known as Count Rumford. And at his death, by founding a professorship in
Harvard College, and donating a prize-fund to the American Academy of
Arts and Sciences at Boston, he showed his interest in her prosperity
and advancement.[37] Nor has the field of vital forces been without
earnest workers belonging to our own country. Professors John W.
Draper[38] and Joseph Henry[39] were among its earliest explorers. And
in 1851, Dr. J. H. Watters, now of St. Louis, published a theory of the
origin of vital force, almost identical with that for which Dr.
Carpenter, of London, has of late received so much credit. Indeed, there
is some reason to believe that Dr. Watters’s essay may have suggested to
the distinguished English physiologist the germs of his own theory.[40]
A paper on this subject by Prof. Joseph Leconte, of Columbia, S. C.,
published in 1859, attracted much attention abroad.[41] The remarkable
results already given on the relation of heat to mental work, which thus
far are unique in science, we owe to Professor J. S. Lombard, of Harvard
College;[42] the very combination of metals used in his apparatus being
devised by our distinguished electrical engineer, Mr. Moses G. Farmer.
Finally, researches conducted by Dr. T. R. Noyes in the Physiological
Laboratory of Yale College, have confirmed the theory that muscular
tissue does not wear during action, up to the point of fatigue;[43] and
other researches by Dr. L. H. Wood have first established the same great
truth for brain-tissue.[44] We need not be ashamed, then, of our part in
this advance in science. Our workers are, indeed, but few; but both they
and their results will live in the records of the world’s progress. More
would there be now of them were such studies more fostered and
encouraged. Self-denying, earnest men are ready to give themselves up to
the solution of these problems, if only the means of a bare subsistence
be allowed them. When wealth shall foster science, science will increase
wealth—wealth pecuniary, it is true: but also wealth of knowledge, which
is far better.

In looking back over the whole of this discussion, I trust that it is
possible to see that the objects which we had in view at its
commencement have been more or less fully attained. I would fain believe
that we now see more clearly the beautiful harmonies of bounteous
nature; that on her many-stringed instrument force answers to force,
like the notes of a great symphony; disappearing now in potential
energy, and anon reappearing as actual energy, in a multitude of forms.
I would hope that this wonderful unity and mutual interaction of force
in the dead forms of inorganic nature, appears to you identical in the
living forms of animal and vegetable life, which make of our earth an
Eden. That even that mysterious, and in many aspects awful, power of
thought, by which man influences the present and future ages, is a part
of this great ocean of energy. But here the great question rolls upon
us, Is it only this? Is there not behind this material substance, a
higher than molecular power in the thoughts which are immortalized in
the poetry of a Milton or a Shakespeare, the art creations of a Michael
Angelo or a Titian, the harmonies of a Mozart or a Beethoven? Is there
really no immortal portion separable from this brain-tissue, though yet
mysteriously united to it? In a word, does this curiously-fashioned body
inclose a soul, God-given and to God returning? Here Science veils her
face and bows in reverence before the Almighty. We have passed the
boundaries by which physical science is enclosed. No crucible, no subtle
magnetic needle can answer now our questions. No word but His who formed
us, can break the awful silence. In presence of such a revelation
Science is dumb, and faith comes in joyfully to accept that higher truth
which can never be the object of physical demonstration.


------------------------------------------------------------------------




                         NOTES AND REFERENCES.


Footnote 1:

  HUMBOLDT, Views of Nature, Bohn’s ed., London, 1850, p. 380. This
  allegory did not appear in the first edition of the Views of Nature.
  In the preface to the second edition the author gives the following
  account of its origin: “Schiller,” he says, “in remembrance of his
  youthful medical studies, loved to converse with me, during my long
  stay at Jena, on physiological subjects.” * * * “It was at this period
  that I wrote the little allegory on Vital Force, called The Rhodian
  Genius. The predilection which Schiller entertained for this piece,
  which he admitted into his periodical, _Die Horen_, gave me courage to
  introduce it here.” It was published in _Die Horen_ in 1795.

Footnote 2:

  HUMBOLDT, _op. cit._, p. 386. In his _Aphorismi ex doctrina
  Physiologiæ chemicæ Plantarum_, appended to his _Flora Fribergensis
  subterranea_, published in 1793, Humboldt had said “Vim internam, quæ
  chymicæ affinitatis vincula resolvit, atque obstat, quominus elementa
  corporum libere conjungantur, vitalem vocamus.” “That internal force,
  which dissolves the bonds of chemical affinity, and prevents the
  elements of bodies from freely uniting, we call vital.” But in a note
  to the allegory above mentioned, added to the third edition of the
  Views of Nature in 1849, he says: “Reflection and prolonged study in
  the departments of physiology and chemistry have deeply shaken my
  earlier belief in peculiar so-called vital forces. In the year 1797, *
  * * I already declared that I by no means regarded the existence of
  these peculiar vital forces as established.” And again: “The
  difficulty of satisfactorily referring the vital phenomena of the
  organism to physical and chemical laws depends chiefly (and almost in
  the same manner as the prediction of meteorological processes in the
  atmosphere) on the complication of the phenomena, and on the great
  number of the simultaneously acting forces as well as the conditions
  of their activity.”

Footnote 3:

  Compare HENRY BENCE JONES, Croonian Lectures on Matter and Force.
  London, 1868, John Churchill & Sons.

Footnote 4:

  Ib., Preface, p. vi.

Footnote 5:

  RANKINE, W. J. M., Philosophical Magazine, Feb., 1853. Also Edinburgh
  Philosophical Journal, July, 1855.

Footnote 6:

  ARMSTRONG, Sir WM. In his address as President of the British
  Association for the Advancement of Science. Rep. Brit. Assoc., 1863,
  li.

Footnote 7:

  GROVE, W. R., in 1842. Compare “Nature” i, 335, Jan. 27, 1870. Also
  Appleton’s Journal, iii, 324, Mch. 19, 1870.

Footnote 8:

  Id., in Preface to The Correlation of Physical Forces, 4th ed.
  Reprinted in The Correlation and Conservation of Forces, edited by E.
  L. Youmans, p. 7. New York, 1865, D. Appleton & Co.

Footnote 9:

  Id., ib., Am. ed., p. 33 et seq.

Footnote 10:

  JOULE, J. P., Philosophical Transactions, 1850, p. 61.

Footnote 11:

  See American Journal of Science, II, xxxvii, 296, 1864.

Footnote 12:

  The work (W) done by a moving body is commonly expressed by the
  formula W = MV^2, in which M, or the mass of the body, is equal to
  w/2g; _i.e._, to the weight divided by twice the intensity of gravity.
  The work done by our cannon-ball then, would be (1 × (1100)^2)/(2 ×
  64⅓) = 9,404·14 foot-tons. If, further, we assume the resisting body
  to be of such a character as to bring the ball to rest in moving ¼ of
  an inch, then the final pressure would be 9,404·14 × 12 × 4 =
  451,398·7 tons. But since, “in the case of a perfectly elastic body,
  or of a resistance proportional to the advance of the center of
  gravity of the impinging body from the point at which contact first
  takes place, the final pressure (provided the body struck is perfectly
  rigid) is double what would occur were the stoppage to occur at the
  end of a corresponding advance against a uniform resistance,” this
  result must be multiplied by two; and we get (451,398·7 × 2) 902,797
  tons as the crushing pressure of the ball under these conditions.
  Note: The author’s thanks are due to his friends Pres. F. A. P.
  Barnard and Mr. J. J. Skinner for suggestions on the relation of
  impact to statical pressure.

Footnote 13:

  The unit of impact being that given by a body weighing one pound and
  moving one foot a second, the impact of such a body falling from a
  hight of 772 feet—the velocity acquired being 222¼ feet per second
  (=√(2sg))—would be 1 × (222¼)^2 = 49,408 units, the equivalent in
  impact of one heat-unit. A cannon-ball weighing 1000 lbs. and moving
  1100 feet a second would have an impact of (1100)^2 × 1000 =
  1,210,000,000 units. Dividing this by 49,408, the quotient is 24489
  heat units, the equivalent of the impact. The specific heat of iron
  being ·1138, this amount of heat would raise the temperature of one
  pound of iron 215.191° F. (24,489 × ·1138) or of 1000 pounds of iron
  215° F. 24489 pounds of water heated one degree, is equal to 136½
  pounds, or 17 gallons U. S., heated 180 degrees; _i.e._, from 32° to
  212° F.

Footnote 14:

  Assuming the density of the earth to be 5·5, its weight would be
  6,500,000,000,000,000,000,000 tons, and its impact—by the formula
  given above—would be 1,025,000,000,000,000,000,000,000,000,000
  foot-tons. Making the same supposition as in the case of our
  cannon-ball, the final pressure would be that here stated.

Footnote 15:

  TYNDALL, J., Heat considered as a mode of Motion; Am. ed., p. 57, New
  York, 1863.

Footnote 16:

  RANKINE (The Steam-engine and other prime Movers, London, 1866,) gives
  the efficiency of Steam-engines as from 1-15th to 1-20th of the heat
  of the fuel.

  ARMSTRONG, Sir WM., places this efficiency at 1-10th as the maximum.
  In practice, the average result is only 1-30th. Rep. Brit. Assoc.,
  1863, p. liv.

  HELMHOLTZ, H. L. F., says: “The best expansive engines give back as
  mechanical work only eighteen per cent. of the heat generated by the
  fuel.” Interaction of Natural Forces, in Correlation and Conservation
  of Forces, p. 227.

Footnote 17:

  THOMSEN, JULIUS, Poggendorff’s Annalen, cxxv, 348. Also in abstract in
  Am. J. Sci., II, xli, 396, May, 1866.

Footnote 18:

  American Journal of Science, II, xli, 214, March, 1866.

Footnote 19:

  In this calculation the annual evaporation from the ocean is assumed
  to be about 9 feet. (See Dr. BUIST, quoted in Maury’s Phys. Geography
  of the Sea, New York, 1861, p. 11.) Calling the water-area of our
  globe 150,000,000 square miles, the total evaporation in tons per
  minute, would be that here given. Inasmuch as 30,000 pounds raised
  one-foot high is a horse-power, the number of horse-powers necessary
  to raise this quantity of water 3½ miles in one minute is
  2,757,000,000,000. This amount of energy is precisely that set free
  again when this water falls as rain.

Footnote 20:

  Compare ODLING, WM., Lectures on Animal Chemistry, London, 1866. “In
  broad antagonism to the doctrines which only a few years back were
  regarded as indisputable, we now find that the chemist, like the
  plant, is capable of producing from carbonic acid and water a whole
  host of organic bodies, and we see no reason to question his ultimate
  ability to reproduce all animal and vegetable principles whatsoever.”
  (p. 52.)

  “Already hundreds of organic principles have been built up from their
  constituent elements, and there is now no reason to doubt our
  capability of producing all organic principles whatsoever in a similar
  manner.” (p. 58.)

  Dr. Odling is the successor of Faraday as Fullerian Professor of
  Chemistry in the Royal Institution of Great Britain.

Footnote 21:

  MARSHALL, JOHN, Outlines of Physiology, American edition, 1868, p.
  916.

Footnote 22:

  FRANKLAND, EDWARD, On the Source of Muscular Power, Proc. Roy. Inst.,
  June 8, 1866; Am. J. Sci., II, xlii, 393, Nov. 1866.

Footnote 23:

  LIEBIG, JUSTUS VON, Die organische Chemie in ihrer Anwendung auf
  Physiologie und Pathologie, Braunschweig, 1842. Also in his Animal
  Chemistry, edition of 1852 (Am. ed., p. 26), where he says “Every
  motion increases the amount of organized tissue which undergoes
  metamorphosis.”

Footnote 24:

  Compare DRAPER, JOHN WM. Human Physiology.

  PLAYFAIR, LYON, On the Food of Man in relation to his useful work,
  Edinburgh, 1865. Proc. Roy. Inst., Apr. 28, 1865.

  RANKE, Tetanus eine Physiologische Studie, Leipzig, 1865.

  ODLING, _op. cit._

Footnote 25:

  VOIT, E., Untersuchungen über den Einfluss des Kochsalzes, des
  Kaffees, und der Muskelbewegungen auf den Stoffwechsel, Munich, 1860.

  SMITH, E., Philosophical Transactions, 1861, 747.

  FICK, A., and WISLICENUS, J., Phil. Mag., IV, xxxi, 485.

  FRANKLAND, E., _loc. cit._

  NOYES, T. R., American Journal Medical Sciences, Oct. 1867.

  PARKES, E. A., Proceedings Royal Society, xv, 339; xvi, 44.

Footnote 26:

  SMITH, EDWARD, Philosophical Transactions, 1859, 709.

Footnote 27:

  Authorities differ as to the amount of energy converted by the
  steam-engine. (See Note 16.) Compare MARSHALL, _op. cit._, p. 918.
  “Whilst, therefore, in an engine one-twentieth part only of the fuel
  consumed is utilized as mechanical power, one-fifth of the food
  absorbed by man is so appropriated.”

Footnote 28:

  HEIDENHAIN, Mechanische Leistung Wärmeentwickelung und Stoffumsatz bei
  der Muskelthätigkeit, Breslau, 1864.

  See also HAUGHTON, SAMUEL, On the Relation of Food to work, published
  in “Medicine in Modern Times,” London, 1869, Macmillan & Co.

Footnote 29:

  HEIDENHAIN, _op. cit._ Also by FICK, Untersuchungen über
  Muskel-arbeit, Basel, 1867. Compare also “Nature,” i, 159, Dec. 9,
  1869.

Footnote 30:

  DU BOIS-REYMOND, EMIL, On the time required for the transmission of
  volition and sensation through the nerves, Proc. Roy. Inst. Also in
  Appendix to Bence Jones’s Croonian lectures.

Footnote 31:

  MARSHALL, _op. cit._, p. 227.

Footnote 32:

  MELLONI, Ann. Ch. Phys., xlviii, 198.

  See also NOBILI, Bibl. Univ., xliv, 225, 1830; lvii, 1, 1834.

Footnote 33:

  The apparatus employed is illustrated and fully described in
  Brown-Sequard’s Archives de Physiologie, i, 498, June, 1868. By it the
  1-4000th of a degree Centigrade may be indicated.

Footnote 34:

  LOMBARD, J. S., New York Medical Journal, v, 198, June, 1867. [A part
  of these facts were communicated to me directly by their discoverer.]

Footnote 35:

  WOOD, L. H., On the influence of Mental activity on the Excretion of
  Phosphoric acid by the Kidneys. Proceedings Connecticut Medical
  Society for 1869, p. 197.

Footnote 36:

  On this question of vital force, see LIEBIG, Animal Chemistry. “The
  increase of mass in a plant is determined by the occurrence of a
  decomposition which takes place in certain parts of the plant under
  the influence of light and heat.”

  “The modern science of Physiology has left the track of Aristotle. To
  the eternal advantage of science, and to the benefit of mankind it no
  longer invents a _horror vacui_, a _quinta essentia_, in order to
  furnish credulous hearers with solutions and explanations of
  phenomena, whose true connection with others, whose ultimate cause is
  still unknown.”

  “All the parts of the animal body are produced from a peculiar fluid
  circulating in its organism, by virtue of an influence residing in
  every cell, in every organ, or part of an organ.”

  “Physiology has sufficiently decisive grounds for the opinion that
  every motion, every manifestation of force, is the result of a
  transformation of the structure or of its substance; that every
  conception, every mental affection, is followed by changes in the
  chemical nature of the secreted fluids; that every thought, every
  sensation is accompanied by a change in the composition of the
  substance of the brain.”

  “All vital activity arises from the mutual action of the oxygen of the
  atmosphere and the elements of the food.”

  “As, in the closed galvanic circuit, in consequence of certain changes
  which an inorganic body, a metal, undergoes when placed in contact
  with an acid, a certain something becomes cognizable by our senses,
  which we call a current of electricity; so in the animal body, in
  consequence of transformations and changes undergone by matter
  previously constituting a part of the organism, certain phenomena of
  motion and activity are perceived, and these we call life, or
  vitality.”

  “In the animal body we recognize as the ultimate cause of all force
  only one cause, the chemical action which the elements of the food and
  the oxygen of the air mutually exercise on each other. The only known
  ultimate cause of vital force, either in animals or in plants, is a
  chemical process.”

  “If we consider the force which determines the vital phenomena as a
  property of certain substances, this view leads of itself to a new and
  more rigorous consideration of certain singular phenomena, which these
  very substances exhibit, in circumstances in which they no longer make
  a part of living organisms.”

  Also OWEN, RICHARD, (Derivative Hypothesis of Life and Species,
  forming the 40th chapter of his Anatomy of Vertebrates, republished in
  Am. J. Sci., II, xlvii, 33, Jan. 1869.) “In the endeavor to clearly
  comprehend and explain the functions of the combination of forces
  called ‘brain,’ the physiologist is hindered and troubled by the views
  of the nature of those cerebral forces which the needs of dogmatic
  theology have imposed on mankind.” * *

  “Religion pure and undefiled, can best answer how far it is righteous
  or just to charge a neighbor with being unsound in his principles who
  holds the term ‘life’ to be a sound expressing the sum of living
  phenomena; and who maintains these phenomena to be modes of force into
  which other forms of force have passed, from potential to active
  states, and reciprocally, through the agency of these sums or
  combinations of forces impressing the mind with the ideas signified by
  the terms ‘monad,’ ‘moss,’ ‘plant,’ or ‘animal.’”

  And HUXLEY, THOS. H., “On the Physical Basis of Life,” University
  Series, No. 1. College Courant, 1870.

  _Per contra_, see the Address of Dr. F. A. P. Barnard, as retiring
  President, before the Am. Assoc. for the Advancement of Science,
  Chicago meeting, August, 1868. “Thought cannot be a physical force,
  because thought admits of no measure.”

  GOULD, BENJ. APTHORP, Address as retiring President, before the
  American Association at its Salem meeting, Aug., 1869.

  BEALE, LIONEL S., “Protoplasm, or Life, Matter, and Mind.” London,
  1870. John Churchill & Sons.

Footnote 37:

  For an excellent account of this distinguished man, see Youmans’s
  Introduction to the Correlation and Conservation of Forces, p. xvii.

Footnote 38:

  DRAPER, J. W., _loc. cit._

Footnote 39:

  HENRY, JOSEPH, Agric. Rep. Patent Office, 1857, 440.

Footnote 40:

  WATTERS, J. H., An Essay on Organic, or Life-force. Written for the
  degree of Doctor of Medicine in the University of Pennsylvania,
  Philadelphia, 1851. See also St. Louis Medical and Surgical Journal,
  II, v, Nos. 3 and 4, 1868; Dec. 1868, and Nov. 10, 1869.

Footnote 41:

  LECONTE, JOSEPH, The Correlation of Physical, Chemical and Vital
  Force, and the Conservation of Force in Vital Phenomena. American
  Journal of Science, II, xxviii, 305, Nov. 1859.

Footnote 42:

  LOMBARD, J. S., _loc. cit._

Footnote 43:

  NOYES, T. R., _loc. cit._

Footnote 44:

  WOOD, L. H., _loc. cit._


------------------------------------------------------------------------




                     _AS REGARDS PROTOPLASM, ETC._




------------------------------------------------------------------------




                            PREFATORY NOTE.


The substance of the greater part of this paper, which has been in the
present form for some time, was delivered, as a lecture, at a
Conversazione of the Royal College of Physicians of Edinburgh, in the
Hall of the College, on the evening of Friday, the 30th of April last.

It will be found to support itself, so far as the facts are concerned,
on the most recent German physiological literature, as represented by
Rindfleisch, Kühne, and especially Stricker, with which last, for the
production of his “Handbuch,” there is associated every great
histological name in Germany.

    EDINBURGH, _October, 1869_.




------------------------------------------------------------------------




                      AS REGARDS PROTOPLASM, ETC.


It is a pleasure to perceive Mr. Huxley open his clear little essay with
what we may hold, perhaps, to be the manly and orthodox view of the
character and products of the French writer, Auguste Comte. “In applying
the name of ‘the new philosophy’ to that estimate of the limits of
philosophical inquiry which he” (Professor Huxley), “in common with many
other men of science, holds to be just,” the Archbishop of York
confounds, it seems, this new philosophy with the Positive philosophy of
M. Comte; and thereat Mr. Huxley expresses himself as greatly
astonished. Some of us, for our parts, may be inclined at first to feel
astonished at Mr. Huxley’s astonishment; for the school to which, at
least on the philosophical side, Mr. Huxley seems to belong, is even
notorious for its prostration before Auguste Comte, whom, especially, so
far as method and systematization are concerned, it regards as the
greatest intellect since Bacon. For such, as it was the opinion of Mr.
Buckle, is understood to be the opinion also of Messrs. Grote, Bain, and
Mill. In fact, we may say that such is commonly and currently considered
the characteristic and distinctive opinion of that whole perverted or
inverted reaction which has been called the _Revulsion_. That is to say,
to give this word a moment’s explanation, that the Voltaires and Humes
and Gibbons having long enjoyed an immunity of sneer at man’s blind
pride and wretched superstition—at _his_ silly non-natural honor and
_her_ silly non-natural virtue—a reaction had set in, exulting in
poetry, in the splendor of nature, the nobleness of man, and the purity
of woman, from which reaction again we have, almost within the last
decennium, been revulsively, as it were, called back,—shall we say by
some “bolder” spirits—the Buckles, the Mills, &c.?—to the old
illumination or enlightenment of a hundred years ago, in regard to the
weakness and stupidity of man’s pretensions over the animality and
materiality that limit him. Of this revulsion, then, as said, a main
feature, especially in England, has been prostration before the vast
bulk of Comte; and so it was that Mr. Huxley’s protest in this
reference, considering the philosophy he professed, had that in it to
surprise at first. But if there was surprise, there was also pleasure;
for Mr. Huxley’s estimate of Comte is undoubtedly the right one. “So far
as I am concerned,” he says, “the most reverend prelate” (the Archbishop
of York) “might dialectically hew M. Comte in pieces as a modern Agag,
and I should not attempt to stay his hand; for, so far as my study of
what specially characterizes the Positive philosophy has led me, I find
therein little or nothing of any scientific value, and a great deal
which is as thoroughly antagonistic to the very essence of science as
anything in ultramontane Catholicism.” “It was enough,” he says again,
“to make David Hume turn in his grave, that here, almost within earshot
of his house, an instructed audience should have listened without a
murmur while his most characteristic doctrines were attributed to a
French writer of fifty years’ later date, in whose dreary and verbose
pages we miss alike the vigor of thought and the exquisite clearness of
style of the man whom I make bold to term the most acute thinker of the
eighteenth century—even though that century produced Kant.”

Of the doctrines themselves which are alluded to here, I shall say
nothing now; but of much else that is said, there is only to be
expressed a hearty and even gratified approval. I demur, to be sure, to
the exaltation of Hume over Kant—high as I place the former. Hume, with
infinite fertility, surprised us, it may be said, perhaps, into
attention on a great variety of points which had hitherto passed
unquestioned; but, even on these points, his success was of an
interrupted, scattered and inconclusive nature. He set the world adrift,
but he set man too, reeling and miserable, adrift with it. Kant, again,
with gravity and reverence, desired to refix, but in purity and truth,
all those relations and institutions which alone give value to
existence—which alone _are_ humanity, in fact—but which Hume, with
levity and mockery, had approached to shake. Kant built up again an
entire new world for us of knowledge and duty, and, in a certain way,
even belief; whereas Hume had sought to dispossess us of every support
that man as man could hope to cling to. In a word, with _at least_ equal
fertility, Kant was, as compared with Hume, a graver, deeper, and, so to
speak, a more consecutive, more comprehensive spirit. Graces there were
indeed, or even, it may be said, subtleties, in which Hume had the
advantage perhaps. He is still in England an unsurpassed master of
expression—this, certainly, in his History, if in his Essays he somewhat
baffles his own self by a certain labored breadth of conscious fine
writing, often singularly inexact and infelicitous. Still Kant, with
reference to his products, must be allowed much the greater importance.
In the history of philosophy he will probably always command as
influential a place in the modern world as Socrates in the ancient;
while, as probably, Hume will occupy at best some such position as that
of Heraclitus or Protagoras. Hume, nevertheless, if equal to Kant, must,
in view at once of his own subjective ability and his enormous
influence, be pronounced one of the most important of writers. It would
be difficult to rate too high the value of his French predecessors and
contemporaries as regards purification of their oppressed and corrupt
country; and Hume must be allowed, though with less call, to have
subserved some such function in the land we live in. In preferring Kant,
indeed, I must be acquitted of an undue partiality; for all that
appertains to personal bias was naturally, and by reason of early and
numerous associations, on the side of my countryman.

Demurring, then, to Mr. Huxley’s opinion on this matter, and postponing
remark on the doctrines to which he alludes, I must express a hearty
concurrence with every word he utters on Comte. In him I too “find
little or nothing of any scientific value.” I too have been lost in the
mere mirage and sands of “those dreary and verbose pages;” and I
acknowledge in Mr. Huxley’s every word the ring of a genuine experience.
M. Comte was certainly a man of some mathematical and scientific
proficiency, as well as of quick but biased intelligence. A member of
the _Aufklärung_, he had seen the immense advance of physical science
since Newton, under, as is usually said, the method of Bacon; and, like
Hume, like Reid, like Kant, _who had all anticipated him in this_, he
sought to transfer that method to the domain of mind. In this he failed;
and though in a sociological aspect he is not without true glances into
the present disintegration of society and the conditions of it, anything
of importance cannot be claimed for him. There is not a sentence in his
book that, in the hollow elaboration and windy pretentiousness of its
build, is not an exact type of its own constructor. On the whole,
indeed, when we consider the little to which he attained, the empty
inflation of his claims, the monstrous and maniacal self-conceit into
which he was _exalted_, it may appear, perhaps, that charity to M. Comte
himself, to say nothing of the world, should induce us to wish that both
his name and his works were buried in oblivion. Now, truly, that Mr.
Huxley (the “call” being for the moment his) has so pronounced himself,
especially as the facts of the case are exactly and absolutely what he
indicates, perhaps we may expect this consummation not to be so very
long delayed. More than those members of the revulsion already
mentioned, one is apt to suspect, will be anxious now to beat a retreat.
Not that this, however, is so certain to be allowed them; for their
estimate of M. Comte is a valuable element in the estimate of
themselves.

Frankness on the part of Mr. Huxley is not limited to his opinion of M.
Comte; it accompanies us throughout his whole essay. He seems even to
take pride, indeed, in naming always and everywhere his object at the
plainest. That object, in a general point of view, relates, he tells us,
solely to materialism, but with a double issue. While it is his declared
purpose, in the first place, namely, to lead us into materialism, it is
equally his declared purpose, in the second place, to lead us out of
materialism. On the first issue, for example, he directly warns his
audience that to accept the conclusions which he conceives himself to
have established on Protoplasm, is to accept these also: That “all vital
action” is but “the result of the molecular forces” of the physical
basis; and that, by consequence, to use his own words to his audience,
“the thoughts to which I am now giving utterance, and your thoughts
regarding them, are but the expression of molecular changes in that
matter of life which is the source of our other vital phenomena.” And,
so far, I think, we shall not disagree with Mr. Huxley when he says that
“most undoubtedly the terms of his propositions are distinctly
materialistic.” Still, on the second issue, Mr. Huxley asserts that he
is “individually no materialist.” “On the contrary, he believes
materialism to involve grave philosophical error;” and the “union of
materialistic terminology with the repudiation of materialistic
philosophy” he conceives himself to share “with some of the most
thoughtful men with whom he is acquainted.” In short, to unite both
issues, we have it in Mr. Huxley’s own words, that it is the single
object of his essay “to explain how such a union is not only consistent
with, but necessitated by, sound logic;” and that, accordingly, he will,
in the first place, “lead us through the territory of vital phenomena to
the materialistic slough,” while pointing out, in the second, “the sole
path by which, in his judgment, extrication is possible.” Mr. Huxley’s
essay, then, falls evidently into two parts; and of these two parts we
may say, further, that while the one—that in which he leads us into
materialism—will be predominatingly physiological, the other—or that in
which he leads us out of materialism—will be predominatingly
philosophical. Two corresponding parts would thus seem to be prescribed
to any full discussion of the essay; and of these, in the present needs
of the world, it is evidently the latter that has the more promising
theme. The truth is, however, that Mr. Huxley, after having exerted all
his strength in his first part to throw us into “the materialistic
slough,” by _clear necessity of knowledge_, only calls to us, in his
second part, to come out of this slough again, on the somewhat _obscure
necessity of ignorance_. This, then, is but a lop-sided balance, where a
scale in the air only seems to struggle vainly to raise its
well-weighted fellow on the ground. Mr. Huxley, in fact, possesses no
remedy for materialism but what lies in the expression that, while he
knows not what matter is in itself, he certainly knows that casualty is
but contingent succession; and thus, like the so-called “philosophy” of
the Revulsion, Mr. Huxley would only mock us into the intensest
dogmatism on the one side by a fallacious reference to the intensest
scepticism on the other.

The present paper, then, will regard mainly Mr. Huxley’s argument _for_
materialism, but say what is required, at the same time, on his alleged
argument—which is merely the imaginary, or imaginative, impregnation of
ignorance—_against_ it.

Following Mr. Huxley’s own steps in his essay, the course of his
positions will be found to run, in summary, thus:—

What is meant by the physical basis of life is, that there is one kind
of matter common to all living beings, and it is named protoplasm. No
doubt it may appear at first sight that, in the various kinds of living
beings, we have only _difference_ before us, as in the lichen on the
rock and the painter that paints it,—the microscopic animalcule or
fungus and the Finner whale or Indian fig,—the flower in the hair of a
girl and the blood in her veins, etc. Nevertheless, throughout these and
all other diversities, there really exists a threefold _unity_—a unity
of faculty, a unity of form, and a unity of substance.

On the first head, for example, or as regards faculty, power, the
action exhibited, there are but three categories of _human_
activity—contractility, alimentation, and reproduction; and there are
no fewer for the _lower_ forms of life, whether animal or vegetable.
In the nettle, for instance, we find the woody case of its sting lined
by a granulated, semi-fluid layer, that is possessed of contractility.
But in this respect—that is, in the possession of contractile
substance—other plants are as the nettle, and all animals are as
plants. Protoplasm—for the nettle-layer alluded to is protoplasm—is
common to the whole of them. The difference, in short between the
powers of the lowest plant or animal and those of the highest is one
only of degree and not of kind.

But, on the second head, it is not otherwise in form, or manifested
external appearance and structure. Not the sting only, but the whole
nettle, is made up of protoplasm; and of all the other vegetables the
nettle is but a type. Nor are animals different. The colorless
blood-corpuscles in man and the rest are identical with the protoplasm
of the nettle; and both he and they consisted at first only of an
aggregation of such. Protoplasm is the common constituent—the common
origin. At last, as at first, all that lives, and every part of all that
lives, are but nucleated or unnucleated, modified or unmodified,
protoplasm.

But, on the third head, or with reference to unity of substance, to
internal composition, chemistry establishes this also. All forms of
protoplasm, that is, consist alike of carbon, hydrogen, oxygen, and
nitrogen, and behave similarly under similar reagents.

So, now, a uniform character having in this threefold manner been proved
for protoplasm, what is its origin, and what its fate? Of these the
latter is not far to seek. The fate of protoplasm is death—death into
its chemical constituents; and this determines its origin also.
Protoplasm can originate only in that into which it dies,—the
elements—the carbon, hydrogen, oxygen, and nitrogen—of which it was
found to consist. Hydrogen, with oxygen, forms water; carbon, with
oxygen, carbonic acid; and hydrogen, with nitrogen, ammonia. Similarly,
water, carbonic acid and ammonia form, in union, protoplasm. The
influence of pre-existing protoplasm only determines combination in
_its_ case, as that of the electric spark determines combination in the
case of water. Protoplasm, then, is but an aggregate of physical
materials, exhibiting in combination—only as was to be expected—new
properties. The properties of water are not more different from those of
hydrogen and oxygen than the properties of protoplasm are different from
those of water, carbonic acid, and ammonia. We have the same warrant to
attribute the consequences to the premises in the one case as in the
other. If, on the first stage of combination, represented by that of
water, _simples_ could unite into something so different from
themselves, why, on the second stage of combination, represented by that
of protoplasm, should not _compounds_ similarly unite into something
equally different from themselves? If the constituents are credited with
the properties _there_, why refuse to credit the constituents with the
properties _here_? To the constituents of protoplasm, in truth, any new
element, named vitality, has no more been added, than to the
constituents of water any new element, named aquosity. Nor is there any
logical halting place between this conclusion and the further and final
one: That all vital action whatever, intellectual included, is but the
result of the molecular forces of the protoplasm which displays it.

These sentences will be acknowledged, I think, fairly to represent Mr.
Huxley’s relative deliverances, and, consequently, as I may be allowed
to explain again, the only important—while much the larger—part of the
whole essay. Mr. Huxley, that is, while devoting fifty paragraphs to our
physiological immersion in the “materialistic slough,” grants but
one-and-twenty towards our philosophical escape from it; the fifty
besides being, so to speak, in reality the wind, and the one-and-twenty
only the whistle for it. What these latter say, in effect, is no more
than this, that,—matter being known not in itself but only in its
qualities, and cause and effect not in their nexus but only in their
sequence,—matter may be spirit or spirit matter, cause effect or effect
cause—in short, for aught that Mr. Huxley more than phenomenally knows,
this may be that or that this, first second, or second first, but the
conclusion shall be this, that he will lay out all our knowledge
materially, and we may lay out all our ignorance immaterially—if we
will. Which reasoning and conclusion, I may merely remark, come
precisely to this: That Mr. Huxley—who, hoping yet to see each object (a
pin, say) not in its qualities but in _itself_, still, consistently
antithetic, cannot believe in the extinction of fire by water or of life
by the rope, for any _reason_ or for any _necessity_ that lies in the
nature of the case, but simply for the habit of the thing—has not yet
put himself at home with the metaphysical categories of _substance_ and
_casualty_; thanks, perhaps, to those guides of his whom we, the amusing
Britons that we are, bravely proclaim “the foremost thinkers of the
day”!

The matter and manner of the whole essay are now fairly before us, and I
think that, with the approbation of the reader, its procedure,
generally, may be described as an attempt to establish, not by any
complete and systematic induction, but by a variety of partial and
illustrative assertions, two propositions. Of these propositions the
first is, That all animal and vegetable organisms are essentially alike
in power, in form, and in substance; and the second, That all vital and
intellectual functions are the properties of the molecular disposition
and changes of the material basis (protoplasm) of which the various
animals and vegetables consist. In both propositions, the agent of proof
is this same alleged material basis of life, or protoplasm. For the
first of them, all animal and vegetable organisms shall be identified in
protoplasm; and for the second, a simple chemical analogy shall assign
intellect and vitality to the molecular constituents of the protoplasm,
in connection with which they are at least exhibited.

In order, then, to obtain a footing on the ground offered us, the first
question we naturally put is, What is Protoplasm? And an answer to this
question can be obtained only by a reference to the historical progress
of the physiological cell theory.

That theory may be said to have wholly grown up since John Hunter wrote
his celebrated work ‘On the Nature of the Blood,’ etc. New growths, to
Hunter, depended on an exudation of the plasma of the blood, in which,
by virtue of its own _plasticity_, vessels formed, and conditioned the
further progress. The influence of these ideas seems to have still
acted, even after a conception of the cell was arrived at. For starting
element, Schleiden required an intracellular plasma, and Schwann a
structureless exudation, in which minute granules, if not indeed already
pre-existent, formed, and by aggregation grew into nuclei, round which
singly the production of a membrane at length enclosed a cell. It was
then that, in this connection, we heard of the terms blastema and
cyto-blastema. The theory of the vegetable cell was completed earlier
than that of the animal one. Completion of this latter, again, seems to
have been first effected by Schwann, after Müller had insisted on the
analogy between animal and vegetable tissue, and Valentin had
demonstrated a nucleus in the animal cell, as previously Brown in the
vegetable one. But assuming Schwann’s labor, and what surrounded it, to
have been a first stage, the wonderful ability of Virchow may be said to
have raised the theory of the cell fully to a second stage. Now, of this
second stage, it is the dissolution or resolution that has led to the
emergence of the word Protoplasm.

The body, to Virchow, constituted a free state of individual subjects,
with equal rights but unequal capacities. These were the cells, which
consisted each of an enclosing membrane, and an enclosed nucleus with
surrounding intracellular matrix or matter. These cells, further,
propagated themselves, chiefly by partition or division; and the
fundamental principle of the whole theory was expressed in the dictum,
“_Omnis cellula e cellulâ_.” That is, the nucleus, becoming gradually
elongated, at last parted in the midst; and each half, acting as center
of attraction to the surrounding intracellular matrix or contained
matter, stood forth as a new nucleus to a new cell, formed by division
at length of the original cell.

The first step taken in resolution of this theory was completed by Max
Schultze, preceded by Leydig. This was the elimination of an investing
membrane. Such membrane may, and does, ultimately form; but in the first
instance, it appears, the cell is naked. The second step in the
resolution belongs perhaps to Brücke, though preceded by Bergmann, and
though Max Schultze, Kühne, Haeckel, and others ought to be mentioned in
the same connection. This step was the elimination, or at least
subordination, of the nucleus. The nucleus, we are to understand now, is
necessary neither to the division nor to the existence of the cell.

Thus, then, stripped of its membrane, relieved of its nucleus, what now
remains for the cell? Why, nothing but what _was_ the contained matter,
the intracellular matrix, and _is_—Protoplasm.

In the application of this word itself, however, to the element in
question, there are also a step or two to be noticed. The first step was
Dujardin’s discovery of sarcode; and the second the introduction of the
term protoplasm as the name for the layer of the _vegetable_ cell that
lined the cellulose, and enclosed the nucleus. Sarcode, found in certain
of the lower forms of life, was a simple substance that exhibited powers
of spontaneous contraction and movement. Thus, processes of such simple,
soft, contractile matter are protruded by the rhizopods, and locomotion
by their means effected. Remak first extended the use of the term
protoplasm from the layer which bore that name in the vegetable cell to
the analogous element in the animal cell; but it was Max Schultze, in
particular, who, by applying the name to the intracellular matrix, or
contained matter, when divested of membrane, and by identifying this
substance itself with sarcode, first fairly established protoplasm, name
and thing, in its present prominence.

In this account I have necessarily omitted many subordinate and
intervening steps in the successive establishment of the
_contractility_, superior _importance_, and complete _isolation_ of this
thing to which, under the name of protoplasm, Mr. Huxley of late has
called such vast attention. Besides the names mentioned, there are
others of great eminence in this connection, such as Meyen, Siebold,
Reichert, Ecker, Henle, and Kölliker among the Germans; and among
ourselves, Beale and Huxley himself. John Goodsir will be mentioned
again.

We have now, perhaps, obtained a general idea of protoplasm. Brücke,
when he talks of it as “living cell-body or elementary organism,” comes
very near the leading idea of Mr. Huxley as expressed in his phrase,
“the physiological basis, or matter, of life.” Living cell-body,
elementary organism, primitive living matter—that, evidently, is the
quest of Mr. Huxley. There is aqueous matter, he would say, perhaps,
composed of hydrogen and oxygen, and it is the same thing whether in the
rain-drop or the ocean; so, similarly, there is vital matter, which,
composed of carbon, hydrogen, oxygen, and nitrogen, is the same thing
whether in cryptogams or in elephants, in animalcules or in men. What,
in fact, Mr. Huxley seeks, probably, is living protein—protein, so to
speak, struck into life. Just such appears to him to be the nature of
protoplasm, and in it he believes himself to possess at last _a living
clay_ wherewith to build the whole organic world.

The question, What is Protoplasm? is answered, then; but, for the
understanding of what is to follow, there is still one general
consideration to be premised.

Mr. Huxley’s conception of protoplasm, as we have seen, is that of
living matter, living protein; what we may call, perhaps, elementary
life-stuff. Now, is it quite certain that Mr. Huxley is correct in this
conception? Are we to understand, for example, that cells have now
definitively vanished, and left in their place only a uniform and
universal _matter_ of quite indefinite proportions? No; such an
understanding would be quite wrong. Whatever may be the opinion of the
adherents of the molecular theory of generation, it is certain that all
the great German histologists still hold by the cell, and can hardly
open their mouths without mention of it. I do not allude here to any
special adherents of either nucleus or membrane, but to the most
advanced innovators in both respects; to such men as Schultze and Brücke
and Kühne. These, as we have seen, pretty well confine their attention,
like Mr. Huxley, to the protoplasm. But they do not the less on that
account talk of the cell. For them, it is only in cells that protoplasm
exists. To their view, we cannot fancy protoplasm as so much matter in a
pot, in an ointment-box, any portion of which scooped out in an
ear-picker would be so much life-stuff, and, though a part, quite as
good as the whole. This seems to be Mr. Huxley’s conception, but it is
not theirs. A certain _measure_ goes with protoplasm to constitute it an
organism to them, and worthy of their attention. They refuse to give
consideration to any mere protoplasm-_shred_ that may not have yet
ceased, perhaps, to exhibit all sign of contractility under the
microscope, and demand a protoplasm-_cell_. In short, protoplasm is to
them still distributed into cells, and only that measure of protoplasm
is cell that is adequate to the whole group of vital manifestations.
Brücke, for example, of all innovators probably the most innovating, and
denying, or inclined to deny, both nucleus and membrane, does not
hesitate, according to Stricker, to speak still of cells as
self-complete organisms, that move and grow, that nourish and reproduce
themselves, and that perform specific function. “Omnis cellula e
cellulâ,” is the rubric they work under as much now as ever. The heart
of a turtle, they say, is not a turtle; so neither is a protoplasm-shred
a protoplasm-cell.

This, then, is the general consideration which I think it necessary to
premise; and it seems, almost of itself, to negate Mr. Huxley’s
reasonings in advance, for it warrants us in denying that physiological
clay of which all living things are but bricks baked, Mr. Huxley
intimates, and in establishing in its place cells as before—living cells
that differ infinitely the one from the other, and so differ from the
very first moment of their existence. This consideration shall not be
allowed to pre-termit, however, an examination of Mr. Huxley’s own
proofs, which will only the more and more avail to indicate the
difference suggested.

These proofs, as has been said, would, by means of the single fulcrum of
protoplasm, establish, first, the identity, and, second, the
materiality, of all vegetable and animal life. These are, shortly, the
two propositions which we have already seen, and to which, in their
order, we now pass.

All organisms, then, whether animal or vegetable, have been understood
for some time back to originate in and consist of cells; but the
progress of physiology has _seemed_ now to substitute for cells a single
matter of life, protoplasm; and it is here that Mr. Huxley sees his cue.
Mr. Huxley’s very first word is the “physical basis or matter of life;”
and he supposes “that to many the idea that there is such a thing may be
novel.” This, then, so far, is what is _new_ in Mr. Huxley’s
contribution. He seems to have said to himself, if formerly the whole
world was thought kin in an “ideal” or formal element, organization, I
shall now finally complete this identification in a “physical” or
material element, protoplasm. In short, what at this stage we are asked
to witness in the essay is, the identification of all living beings
whatever in the identity of protoplasm. As there is a single matter,
clay, which is the matter of all bricks, so there is a single matter,
protoplasm, which is the matter of all organisms. “Protoplasm is the
clay of the potter, which, bake it and paint it as he will, remains
clay, separated by artifice, and not by nature, from the commonest brick
or sun-dried clod.” Now here I cannot help stopping a moment to remark
that Mr. Huxley puts emphatically his whole soul into this sentence, and
evidently believes it to be, if we may use the word, a _clincher_. But,
after all, does it say much? or rather, does it say anything? To the
question, “Of what are you made?” the answer, for a long time now, and
by the great mass of human beings who are supposed civilized, has been
“Dust.” Dust, and the same dust, has been allowed to constitute us all.
But materialism has not on that account been the irresistible result.
Attention hitherto—and surely excusably, or even laudably in such a
case—has been given not so much to the dust as to the “potter,” and the
“artifice” by which he could so transform, or, as Mr. Huxley will have
it, _modify_ it. To ask us to say, instead of dust, clay, or even
protoplasm, is not to ask us for much, then, seeing that even to Mr.
Huxley there still remain both the “potter” and his “artifice.”

But to return: To Mr. Huxley, when he says all bricks, being made of
clay, are the same thing, we answer, Yes, undoubtedly, if they are made
of the same clay. That is, the bricks are identical if the clay is
identical; but, on the other hand, by as much as the clay differs will
the bricks differ. And, similarly, all organisms can be identified only
if their composing protoplasm can be identified. To this stake is the
argument of Mr. Huxley bound.

This argument itself takes, as we have seen, a threefold course: Mr.
Huxley will prove his position in this place by reference, firstly, to
unity of faculty; secondly, to unity of form; and thirdly, to unity of
substance. It is this course of proof, then, which we have now to
follow, but taking the question of substance, as simplest, first, and
the others later.

By substance, Mr. Huxley understands the internal or chemical
composition; and, with a mere reference to the action of reagents, he
asserts the protoplasm of all living beings to be an identical
combination of carbon, hydrogen, oxygen, and nitrogen. It is for us to
ask, then, Are all samples of protoplasm identical, first, in their
chemical composition, and, second, under the action of the various
reagents?

On the first clause, we may say, in the first place, towards a proof of
difference which will only cumulate, I hope, that, even should we grant
in all protoplasm an identity of chemical ingredients, what is called
_Allotropy_ may still have introduced no inconsiderable variety. Ozone
is not antozone, nor is oxygen either, though in chemical constitution
all are alike. In the second place, again, we may say that, with
_varying proportions_, the same component parts produce very various
results. By way of illustration, it will suffice to refer to such
different things as the proteids, gluten, albumen, fibrin, gelatine,
etc., compared with the urinary products, urea and uric acid; or with
the biliary products, glycocol, glycocolic acid, bili-rubin,
bili-verdin, etc.; and yet all these substances, varying so much the one
from the other, are, as protoplasm is, compounds of carbon, hydrogen,
oxygen, and nitrogen. But, in the third place, we are not limited to a
_may say_; we can assert the fact that all protoplasm is not chemically
identical. All the tissues of the organism are called protoplasm by Mr.
Huxley; but can we predicate chemical identity of muscle and bone, for
example? In such cases Mr. Huxley, it is true, may bring the word
“modified” into use; but the objection of modification we shall examine
later. In the mean time, we are justified, by Mr. Huxley’s very
argument, in regarding all organized tissues whatever as protoplasm; for
if these tissues are not to be identified in protoplasm, we must suppose
denied what it was his one business to affirm. And it is against that
affirmation that we point to the fact of much chemical difference
obtaining among the tissues, not only in the _proportions_ of their
fundamental elements, but also in the _addition_ (and proportions as
well) of such others as chlorine, sulphur, phosphorus, potash, soda,
lime, magnesia, iron, etc. Vast differences vitally must be legitimately
assumed for tissues that are so different chemically. But, in the fourth
place, we have the authority of the Germans for asserting that the cells
themselves—and they now, to the most advanced, are only protoplasm—do
differ chemically, some being found to contain glycogen, some
cholesterine, some protogon, and some myosin. Now such substances, let
the chemical analogy be what it may, must still be allowed to introduce
chemical difference. In the last place, Mr. Huxley’s analysis is an
analysis of _dead_ protoplasm, and indecisive, consequently, for that
which lives. Mr. Huxley betrays sensitiveness in advance to this
objection; for he seeks to rise above the sensitiveness and the
objection at once by styling the latter “frivolous.” Nevertheless the
Germans say pointedly that it is unknown whether the same elements are
to be referred to the cells after as before death. Kühne does not
consider it proved that living muscle contains syntonin; yet Mr. Huxley
tells us, in his Physiology, that “syntonin is the chief constituent of
muscle and flesh.” In general, we may say, according to Stricker, that
all weight is put now on the examination of living tissue, and that the
difference is fully allowed between that and dead tissue.

On the second clause now, or with regard to the action of reagents,
these must be denied to produce the like result on the various forms of
protoplasm. With reference to temperature, for example, Kühne reports
the movements of the amoeba to be arrested in iced water; while, in the
same medium, the ova of the trout furrow famously, but perish even in a
warmed room. Others, again, we are told, may be actually dried, and yet
live. Of ova in general, in this connection, it is said that they live
or die according as the temperature to which they are exposed differs
little or much from that which is natural to the organisms producing
them. In some, according to Max Schultze, even distilled water is enough
to arrest movement. Now, not to dwell longer here, both amoeba and ova
are to Mr. Huxley pure protoplasm; and such difference of result,
according to difference of temperature, etc., must assuredly be allowed
to point to a difference of original nature. Any conclusion so far,
then, in regard to unity of substance, whether the chemical composition
or the action of reagents be considered, cannot be said to bear out the
views of Mr. Huxley.

What now of the unities of form and power in protoplasm? By form, Mr.
Huxley will be found to mean the general appearance and structure; and
by faculty or power, the action exhibited. Now it will be very easy to
prove that, in neither respect, do all specimens of protoplasm agree.
Mr. Huxley’s representative protoplasm, it appears, is that of the
nettle-sting; and he describes it as a granulated, semi-fluid body,
contractile in mass, and contractile also in detail to the development
of a species of circulation. Stricker, again, speaks of it as a
homogeneous substance, in which any granules that may appear must be
considered of foreign importation, and in which there are no evidences
of circulation. In this last respect, then, that Mr. Huxley should talk
of “tiny Maelstroms,” such as even in the silence of a tropical noon
might stun us, if heard, as “with the roar of a great city,” may be
viewed, perhaps, as a rise into poetry beyond the occasion.

Further, according to Stricker, protoplasm varies almost infinitely in
consistence, in shape, in structure, and in function. In consistence, it
is sometimes so fluid as to be capable of forming in drops; sometimes
semi-fluid and gelatinous; sometimes of considerable resistance. In
shape—for to Stricker the cells are now protoplasm—we have club-shaped
protoplasm, globe-shaped protoplasm, cup-shaped protoplasm,
bottle-shaped protoplasm, spindle-shaped protoplasm—branched, threaded,
ciliated protoplasm,—circle-headed protoplasm—flat, conical,
cylindrical, longitudinal, prismatic, polyhedral, and palisade-like
protoplasm. In structure, again, it is sometimes uniform and sometimes
reticulated into interspaces that contain fluid. In function, lastly—and
here we have entered on the consideration of faculty or power—some
protoplasm is vagrant (so to translate _wandernd_), and of unknown use,
like the colorless blood-corpuscles.

In reference to these, as strengthening the argument, and throwing much
light generally, I break off a moment to say that, very interesting as
they are in themselves, and as Recklinghausen, in especial, has made
them, Mr. Huxley’s theory of them disagrees considerably with the
prevalent German one. He speaks of them as the source of the body in
general, yet, in his Physiology, he talks of the spleen, the lymphatics,
and even the liver—_parts_ of the body—as _their_ source. They are so
few in number that, while Mr. Huxley is thankful to be able to point to
the inside of the lips as a seat for them, they bear to the red
corpuscles only the proportion of 1 to 450. This disproportion, however,
is no bar to Mr. Huxley’s derivation of the latter from the former. But
the fact is questioned. The Germans, generally, for their, part,
describe the colorless, or vagrant, blood-corpuscles as probably media
of conjugation or reparation, but acknowledge their function to be as
yet quite unknown; while Rindfleisch, characterizing the spleen as the
grave of the red, and the womb of the white, corpuscles, evidently
refers the latter to the former. This, indeed, is a matter of direct
assertion with Preyer, who has “shown that pieces of red
blood-corpuscles may be eaten by the amoeboid cells of the frog,” and
holds that the latter (the white corpuscles) proceed directly from the
former (the red corpuscles); so that it seems to be determined in the
mean time that there is no proof of the reverse being the fact.

In function, then, to resume, some protoplasm is vagrant, and of unknown
use. Some again produces pepsine, and some fat. Some at least contains
pigment. Then there is nerve-protoplasm, brain-protoplasm,
bone-protoplasm, muscle-protoplasm, and protoplasm of all the other
tissues, no one of which but produces only its own kind, and is
uninterchangeable with the rest. Lastly, on this head, we have to point
to the overwhelming fact that there is the infinitely different
protoplasm of the various infinitely different plants and animals, in
each of which its own protoplasm, as in the case of that of the various
tissues, but produces its own kind, and is uninterchangeable with that
of the rest.

It may be objected, indeed, that these latter are examples of modified
protoplasm. The objection of modification, as said, we have to see by
itself later; but, in the mean time, it may be asked, Where are we to
begin, _not_ to have modified protoplasm? We have the example of Mr.
Huxley himself, who, in the nettle-sting, begins already with modified
protoplasm; and we have the authority of Rindfleisch for asserting that
“in every different tissue we must look for a different initial term of
the productive series.” This, evidently, is a very strong light on the
original multiplicity of protoplasm, which the consideration, as we have
seen, of the various plants and animals, has made, further, infinite.
This is enough; but there is no wish to evade beginning with the very
beginning—with absolutely pure initial protoplasm, if it can but be
given us in any reference. The simple egg—that, probably is the
beginning—that, probably, is the original identity; yet even there we
find already distribution of the identity into infinite difference.
This, certainly, with reference to the various organisms, but with
reference also to the various tissues. That we regard the egg as the
beginning, and that we do not start, like the smaller exceptional
physiological school, with molecules themselves, depends on this, that
the great Germans so often alluded to, Kühne among them, still trust in
the experiments of Pasteur; and while they do not deny the possibility,
or even the fact, of molecular generation, still feel justified in
denying the existence of any observation that yet unassailably attests a
_generatio æquivoca_. By such authority as this the simple philosophical
spectator has no choice but to take his stand; and therefore it is that
I assume the egg as the established beginning, so far, of all vegetable
and animal organisms. To the egg, too, as the beginning, Mr. Huxley,
though the lining of the nettle-sting is his representative protoplasm,
at least refers. “In the earliest condition of the human organism,” he
says, in allusion to the white (vagrant) corpuscles of the blood, “in
that state in which it has but just become distinguished from the egg in
which it arises, it is nothing but an aggregation of such corpuscles,
and every organ of the body was once no more than such an aggregation.”
Now, in beginning with the egg—an absolute beginning being denied us in
consequence of the pre-existent infinite difference of the egg or eggs
themselves—we may gather from the German physiologists some such account
of the actual facts as this.

The first change signalized in the impregnated egg seems that of
_Furchung_, or furrowing—what the Germans call the _Furchungskugeln_,
the _Dotterkugeln_, form. Then these _Kugeln_—clumps, eminences,
monticles, we may translate the word—break into cells; and these are the
cells of the embryo. Mr. Huxley, as quoted, refers to the whole body,
and every organ of the body, as at first but an aggregation of colorless
blood-corpuscles; but in the very statement which would render the
identity alone explicit, the difference is quite as plainly implicit. As
much as this lies in the word “organs,” to say nothing of “human.” The
cells of the “organs,” to which he refers, are even then
uninterchangeable, and produce but themselves. The Germans tell us of
the _Keimblatt_, the germ-leaf, in which all these organs originate.
This _Blatt_, or leaf, is threefold, it seems; but even these folds are
not indifferent. The various cells have their distinct places in them
from the first. While what in this connection are called the epithelial
and endorthelial tissues spring respectively from the _upper_ and
_under_ leaf, connective tissues, with muscle and blood, spring from the
_middle_ one. Surely in such facts we have a perfect warrant to assert
the initial non-identity of protoplasm, and to insist on this, that,
from the very earliest moment—even literally _ab ovo_—brain-cells only
generate brain-cells, bone-cells bone-cells, and so on.

These considerations on function all concern faculty or power; but we
have to notice now that the characteristic and fundamental form of power
is to Mr. Huxley _contractility_. He even quotes Goethe in proof of
contractility being the main power or faculty of _Man_! Nevertheless it
is to be said at once that, while there are differences in what
protoplasm _is_ contractile, all protoplasm is not contractile, nor
dependent on contractility for its functions. In the former respect, for
example, muscle, while it is the contractile tissue special, is also to
Mr. Huxley protoplasm; yet Stricker asserts the inner construction of
the contractile substance, of which muscle-fibre virtually consists, to
be essentially different from contractile protoplasm. Here, then, we
have the contractile _substance_ proper “essentially different” from the
contractile _source_ proper. In the latter respect, again, we shall not
call in the _un_contractible substances which Mr. Huxley himself
denominates protoplasm—bread, namely, roast mutton, and boiled lobster;
but we may ask where—even in the case of a living body—is the
contractility of white of egg? In this reference, too, we may remark
that Kühne, who divides the protoplasm of the epidermis into three
classes, has been unable to distinguish contractility in his own third
class. Lastly, where, in relation to the protoplasm of the nervous
system, is there evidence of its contractility? Has any one pretended
that thought is but the contraction of the brain; or is it by
contraction that the very nerves operate contraction—the nerves that
supply muscles, namely? Mr. Huxley himself, in his Physiology, describes
nervous action very differently. There _conduction_ is spoken of without
a hint of contraction. Of the higher faculties of man I have to speak
again; but let us just ask where, in the case of any pure
sensation—smell, taste, touch, sound, color—is there proof of any
contraction? Are we to suppose that between the physical cause of heat
without and the mental sensation of heat within, contraction is anywhere
interpolated? Generally, in conclusion here, while reminding of
Virchow’s testimony to the inherent inequalities of cell-capacity, let
us but, on the question of faculty, contrast the kidney and the brain,
even as these organs are viewed by Mr. Huxley. To him the one is but a
sieve for the extrusion of refuse: the other thinks Newton’s ‘Principia’
and Iliads of Homer.

Probably, then, in regard to any continuity in protoplasm of power, of
form, or of substance, we have seen _lacunæ_ enow. Nay, Mr. Huxley
himself can be adduced in evidence on the same side. Not rarely do we
find in his essay admissions of _probability_ where it is _certainty_
that is alone in place. He says, for example, “It is more than probable
that _when_ the vegetable world _is_ thoroughly explored we _shall_ find
all plants in possession of the same powers.” When a conclusion is
decidedly announced, it is rather disappointing to be told, as here,
that the premises are still to collect. “_So far_,” he says again, “as
the conditions of the manifestations of the phenomena of contractility
have _yet_ been studied.” Now, such a _so far_ need not be _very far_;
and we may confess in passing, that from Mr. Huxley the phrase, “the
conditions of the _manifestations_ of the _phenomena_” grates. We hear
again that it is “the rule _rather_ than the exception,” or that
“weighty authorities have _suggested_” that such and such things
“probably occur,” or, while contemplating the nettle-sting, that such
“_possible_ complexity” in other cases “_dawns_ upon one.” On other
occasions he expresses himself to the effect that “perhaps it would not
yet be safe to say that _all_ forms,” etc. Nay, not only does he
directly _say_ that “it is by no means his intention to suggest that
there is no difference between the lowest plant and the highest, or
between plants and animals,” but he directly proves what he says, for he
demonstrates in plants and animals an _essential difference of power_.
Plants _can_ assimilate inorganic matters, animals can _not_, etc.
Again, here is a passage in which he is seen to cut his own “_basis_”
from beneath his own feet. After telling us that all forms of protoplasm
consist of carbon, hydrogen, oxygen, and nitrogen “in very complex
union,” he continues, “To this complex combination, _the nature of which
has never been determined with exactness_, the name of protein has been
applied.” This, plainly, is an identification, on Mr. Huxley’s own part,
of protoplasm and protein; and what is said of the one being necessarily
true of the other, it follows that Mr. Huxley admits the nature of
protoplasm never to have been determined with exactness, and that, even
in his eyes, the _lis_ is still _sub judice_. This admission is
strengthened by the words, too, “If we use this term” (protein) “with
such _caution_ as may properly arise out of our _comparative ignorance_
of the things for which it stands;” which entitle us to recommend, in
consequence “of our _comparative ignorance_ of the things for which it
stands,” “_caution_” in the use of the term protoplasm. In such a state
of the case we cannot wonder that Mr. Huxley’s own conclusion here is:
Therefore “all living matter is more or less albuminoid.” All living
matter is more or less albuminoid! That, indeed, is the single
conclusion of Mr. Huxley’s whole industry; but it is a conclusion that,
far from requiring the intervention of protoplasm, had been reached long
before the word itself had been, in this connection, used.

It is in this way, then, that Mr. Huxley can be adduced in refutation of
himself; and I think his resort to an epigram of Goethe’s for reduction
of the powers of man to those of contraction, digestion, and
reproduction, can be regarded as an admission to the same effect. The
epigram runs thus:—

   “Warum treibt sich das Volk so, und schreit? Es will sich ernähren,
    Kinder zeugen, und die nähren so gut es vermag.
    Weiter bringt es kein Mensch, stell’ er sich wie er auch will.”

That means, quite literally translated, “Why do the folks bustle and
bawl? They want to feed themselves, get children, and then feed them as
best they can; no man does more, let him do as he may.” This, really, is
Mr. Huxley’s sole proof for his classification of the powers of man. Is
it sufficient? Does it not apply rather to the birds of the air, the
fish of the sea, and the beasts of the field, than to man? Did Newton
only feed himself, beget children, and then feed them? Was it impossible
for him to do any more, let him do as he might? And what we ask of
Newton we may ask of all the rest. To elevate, therefore, the passing
whim of mere literary _Laune_ into a cosmical axiom and a proof in
place—this we cannot help adding to the other productions here in which
Mr. Huxley appears against himself.

But were it impossible either for him or us to point to these _lacunæ_,
it would still be our right and our duty to refer to the present
conditions of microscopic science in general as well as in particular,
and to demur to the erection of its _dicta_, constituted as they yet
are, into established columns and buttresses in support of any theory of
life, material or other.

The most delicate and dubious of all the sciences, it is also the
youngest. In its manipulations the slightest change may operate as a
destructive drought, or an equally destructive deluge. Its very tools
may positively create the structure it actually examines. The present
state of the science, and what warrant it gives Mr. Huxley to dogmatize
on protoplasm, we may understand from this avowal of Kühne’s: “To-day we
believe that we see” such or such fact, “but know not that further
improvements in the means of observation will not reveal what is assumed
for certainty to be only illusion.” With such authority to lean on—and
it is the highest we can have—we may be allowed to entertain the
conjecture, that it is just possible that some certainties, even of Mr.
Huxley, may yet reveal themselves as illusions.

But, in resistance to any sweeping conclusions built on it, we are not
confined to a reference to the imperfections involved in the very nature
and epoch of the science itself in general. With yet greater assurance
of carrying conviction with us, we may point in particular to the actual
opinions of its present professors. We have seen already, in the
consideration premised, that Mr. Huxley’s hypothesis of a protoplasm
_matter_ is unsupported, even by the most innovating Germans, who as yet
will not advance, the most advanced of them, beyond a protoplasm-cell;
and that his whole argument is thus sapped in advance. But what
threatens more absolute extinction of this argument still, _all_ the
German physiologists do _not_ accept even the protoplasm-cell.
Rindfleisch, for example, in his recently-published ‘Lehrbuch der
pathologischen Gewebelehre’ speaks of the cell very much as we
understand Virchow to have spoken of it. To him there is in the cell not
only protoplasm but nucleus, and perhaps membrane as well. To him, too,
the cell propagates itself quite as we have been hitherto fancying it to
do, by division of the nucleus, increase of the protoplasm, and ultimate
partition of the cell itself. Yet he knows withal of the opinions of
others, and accepts them in a manner. He mentions Kühne’s account of the
membrane as at first but a mere physical limit of two fluids—a mere
peripheral film or curdling; still he assumes a formal and decided
membrane at last. Even Leydig and Schultze, who shall be the express
eliminators of the membrane—the one by initiation and the other by
consummation—confess that, as regards the cells of certain tissues, they
have never been able to detect in them the absence of a membrane.

As regards the nucleus again, the case is very much stronger. When we
have admitted with Brücke that certain cryptogam cells, with Haeckel
that certain protists, with Cienkowsky that two monads, and with
Schultze that one amoeba, are without nucleus—when we have admitted that
division of the cell _may_ take place without implicating that of the
nucleus—that the movements of the nucleus _may_ be passive and due to
those of the protoplasm—that Baer and Stricker demonstrate the
disappearance of the original nucleus in the impregnated egg,—when we
have admitted this, we have admitted also all that can be said in
degradation of the nucleus. Even those who say all this still attribute
to the nucleus an important and unknown _rôle_, and describe the
formation in the impregnated egg of a new nucleus; while there are
others again who resist every attempt to degrade it. Böttcher asserts
movement for the nucleus, even when wholly removed from the cell;
Neumann points to such movement in dead or dying cells; and there is
other testimony to a like effect, as well as to peculiarities of the
nucleus otherwise that indicate spontaneity. In this reference we may
allude to the weighty opinion of the late Professor Goodsir, who
anticipated in so remarkable a manner certain of the determinations of
Virchow. Goodsir, in that anticipation, wonderfully rich and ingenious
as he is everywhere, is perhaps nowhere more interesting and successful
than in what concerns the nucleus. Of the whole cell, the nucleus is to
him, as it was to Schleiden, Schwann, and others, the most important
element. And this is the view to which I, who have little business to
speak, wish success. This universe is not an accidental cavity, in which
an accidental dust has been accidentally swept into heaps for the
accidental evolution of the majestic spectacle of organic and inorganic
life. That majestic spectacle is a spectacle as plainly for the eye of
reason as any diagram of the mathematician. That majestic spectacle
could have been constructed, was constructed, only in reason, for
reason, and by reason. From beyond Orion and the Pleiades, across the
green hem of earth, up to the imperial personality of man, all, the
furthest, the deadest, the dustiest, is for fusion in the invisible
point of the single Ego—_which alone glorifies it_. _For_ the subject,
and on the model of the subject, all is made. Therefore it is
that—though, precisely as there are acephalous monsters by way of
exception and deformity, there may be also at the very extremity of
animated existence cells without a nucleus—I cannot help believing that
this nucleus itself, as analogue of the subject will yet be proved the
most important and indispensable of all the normal cell-elements. Even
the phenomena of the impregnated egg seem to me to support this view. In
the egg, on impregnation, it seems to me natural (I say it with a smile)
that the old sun that ruled it should go down, and that a new sun,
stronger in the combination of the new and the old, should ascend into
its place!

Be these things as they may, we have now overwhelming evidence before us
for concluding, with reference to Mr. Huxley’s first proposition,
that—in view of the nature of microscopic science—in view of the state
of belief that obtains at present as regards nucleus, membrane, and
entire cell—even in view of the supporters of protoplasm itself—Mr.
Huxley is not authorized to speak of a physical matter of life; which,
for the rest, if granted, would, for innumerable and, as it appears to
me, irrefragable reasons, be obliged to acknowledge for itself, not
identity, but an infinite diversity in power, in form and in substance.

So much for the first proposition in Mr. Huxley’s essay, or that which
concerns protoplasm, as a supposed matter of life, identical itself, and
involving the identity of all the various organs and organisms which it
is assumed to compose. What now of the second proposition, or that which
concerns the materiality at once of protoplasm, and of all that is
conceived to derive from protoplasm? In other words, though, so to
speak, for organic bricks anything like an organic clay still awaits the
proof, I ask, if the bricks are not the same because the clay is not the
same, what if the materiality of the former is equally unsupported by
the materiality of the latter? Or what if the functions of protoplasm
are not properties of its mere molecular constitution?

For this is Mr. Huxley’s second proposition, namely, That all vital and
intellectual functions are but the properties of the molecular
disposition and changes of the material basis (protoplasm) of which the
various animals and vegetables consist. With the conclusions now before
us, it is evident that to enter at all on this part of Mr. Huxley’s
argumentation is, so far as we are concerned, only a matter of grace. In
order that it should have any weight, we must grant the fact, at once of
the existence of a matter of life, and of all organs and organisms being
but aggregates of it. This, obviously, we cannot now do. By way of
hypothesis, however, we may assume it. Let it be granted, then, that
_pro hac vice_ there _is_ a physical basis of life with all the
consequences named; and now let us see how Mr. Huxley proceeds to
establish its materiality.

The whole former part of Mr. Huxley’s essay consists (as said) of fifty
paragraphs, and the argument immediately concerned is confined to the
latter ten of them. This argument is the simple chemical analogy that,
under stimulus of an electric spark, hydrogen and oxygen uniting into an
equivalent weight of water, and, under stimulus of preëxisting
protoplasm, carbon, hydrogen, oxygen, and nitrogen uniting into an
equivalent weight of protoplasm, there is the same warrant for
attributing the properties of the consequent to the properties of the
antecedents in the latter case as in the former. The properties of
protoplasm are, in origin and character, precisely on the same level as
the properties of water. The cases are perfectly parallel. It is as
absurd to attribute a new entity vitality to protoplasm, as a new entity
aquosity to water. Or, if it is by its mere chemical and physical
structure that water exhibits certain properties called aqueous, it is
also by its mere chemical and physical structure that protoplasm
exhibits certain properties called vital. All that is necessary in
either case is, “under certain conditions,” to bring the chemical
constituents together. If water is a molecular complication, protoplasm
is equally a molecular complication, and for the description of the one
or the other there is no change of language required. A new substance
with new qualities results in precisely the same way here, as a new
substance with new qualities there; and the derivative qualities are not
more different from the primitive qualities in the one instance, than
the derivative qualities are different from the primitive qualities in
the other. Lastly, the _modus operandi_ of preëxistent protoplasm is not
more unintelligible than that of the electric spark. The conclusion is
irresistible, then, that all protoplasm being reciprocally convertible,
and consequently identical, the properties it displays, vitality and
intellect included, are as much the result of molecular constitution as
those of water itself.

It is evident, then, that the fulcrum on which Mr. Huxley’s second
proposition rests, is a single inference from a chemical analogy.
Analogy, however, being never identity, is apt to betray. The difference
it hides may be essential, that is, while the likeness it shows may be
inessential—so far as the conclusion is concerned. That this mischance
has overtaken Mr. Huxley here, it will, I fancy, not be difficult to
demonstrate.

The analogy to which Mr. Huxley trusts has two references: one, to
chemical composition, and one to a certain stimulus that determines it.
As regards chemical composition, we are asked, by virtue of the analogy
obtaining, to identify, as equally simple instances of it, protoplasm
here and water there; and, as regards the stimulus in question, we are
asked to admit the action of the electric spark in the one case to be
quite analogous to the action of preëxisting protoplasm in the other. In
both references I shall endeavor to point out that the analogy fails;
or, as we may say it also, that, even to Mr. Huxley, it can only seem to
succeed by discounting the elements of difference that still subsist.

To begin with chemical combination, it is not unjust to demand that the
analogy which must be admitted to exist in that, and a general physical
respect, should not be strained beyond its legitimate limits. Protoplasm
cannot be denied to be a chemical substance; protoplasm cannot be denied
to be a physical substance. As a compound of carbon, hydrogen, oxygen
and nitrogen, it comports itself chemically—at least in ultimate
instance—in a manner not essentially different from that in which water,
as a compound of hydrogen and oxygen, comports itself chemically. In
mere physical aspect, again, it may count quality for quality with water
in the same aspect. In short, so far as it is on chemical and physical
structure that the possession of distinctive properties in any case
depends, both bodies may be allowed to be pretty well on a par. The
analogy must be allowed to hold so far: so far but no farther. One step
farther and we see not only that protoplasm has, like water, a chemical
and physical structure; but that, unlike water, it has also an organized
or organic structure. Now this, on the part of protoplasm, is a
possession in excess; and with relation to that excess there can be no
grounds for analogy. This, perhaps, is what Mr. Huxley has omitted to
consider. When insisting on attributing to protoplasm the qualities it
possessed, because of its chemical and physical structure, if it was for
chemical and physical structure that we attributed to water _its_
qualities, he has simply forgotten the addition to protoplasm of a third
structure that can only be named organic. “If the phenomena exhibited by
water are its properties, so are those presented by protoplasm, living
or dead, its properties.” When Mr. Huxley speaks thus, Exactly so, we
may answer: “living or dead!” That alternative is simply slipped in and
passed; but it is in that alternative that the whole matter lies.
Chemically, dead protoplasm is to Mr. Huxley quite as good as living
protoplasm. As a sample of the article, he is quite content with dead
protoplasm, and even swallows it, he says, in the shape of bread,
lobster, mutton, etc., with all the satisfactory results to be
desired.—Still, as concerns the argument, it must be pointed out that it
is only these that can be placed on the same level as water; and that
living protoplasm is not only unlike water, but it is unlike dead
protoplasm. Living protoplasm, namely, is identical with dead protoplasm
only so far as its chemistry is concerned (if even so much as that); and
it is quite evident, consequently, that difference between the two
cannot depend on that in which they are identical—cannot depend on the
chemistry. Life, then, is no affair of chemical and physical structure,
and must find its explanation in something else. It is thus that, lifted
high enough, the light of the analogy between water and protoplasm is
seen to go out. Water, in fact, when formed from hydrogen and oxygen,
is, in a certain way and in relation to them, no new product; it has
still, like them, only chemical and physical qualities; it is still, as
they are, inorganic. So far as _kind_ of power is concerned, they are
still on the same level. But not so protoplasm, where, with preservation
of the chemical and physical likeness there is the addition of the
unlikeness of life, of organization, and of ideas. But the addition is a
new world—a new and higher world, the world of a self-realizing thought,
the world of an _entelechy_. The change of language objected to by Mr.
Huxley is thus a matter of necessity, for it is _not_ mere molecular
complication that we have any longer before us, and the qualities of the
derivative are essentially and absolutely different from the qualities
of the primitive. If we did invent the term aquosity, then, as an
abstract sign for all the qualities of water, we should really do very
little harm; but aquosity and vitality would still remain essentially
unlike. While for the invention of aquosity there is little or no call,
however, the fact in the other case is that we are not only compelled to
invent, but to _perceive_ vitality. We are quite willing to do as Mr.
Huxley would have us to do: look on, watch the phenomena, and name the
results. But just in proportion to our faithfulness in these respects is
the necessity for the recognition of a new world and a new nomenclature.
There are certainly different states of water, as ice and steam; but the
relation of the solid to the liquid, or of either to the vapor, surely
offers no analogy to the relation of protoplasm dead to protoplasm
alive. That relation is not an analogy but an antithesis, the antithesis
of antitheses. In it, in fact, we are in presence of the one
incommunicable gulf—the gulf of all gulfs—that gulf which Mr. Huxley’s
protoplasm is as powerless to efface as any other material expedient
that has ever been suggested since the eyes of men first looked into
it—the mighty gulf between death and life.

The differences alluded to (they are, in order, organization and life,
the objective idea—design, and the subjective idea—thought), it may be
remarked, are admitted by those very Germans to whom protoplasm, name
and thing, is due. They, the most advanced and innovating of them,
directly avow that there is present in the cell “an architectonic
principle that has not yet been detected.” In pronouncing protoplasm
capable of active or vital movements, they do by that refer, they admit
also, to an immaterial force, and they ascribe the processes exhibited
by protoplasm—in so many words—not to the molecules, but to organization
and life. It is remarked by Kant that “the reason of the specific mode
of existence of every part of a living body lies in the whole, whilst
with dead masses each part bears this reason within itself;” and this
indeed is how the two worlds are differentiated. A drop of water, once
formed, is there passive for ever, susceptible to influence, but
indifferent to influence, and what influence reaches it is wholly from
without. It may be added to, it may be subtracted from; but infinitely
apathetic quantitatively, it is qualitatively independent. It is
indifferent to its own physical parts. It is without contractility,
without alimentation, without reproduction, without specific function.
Not so the cell, in which the parts are dependent on the whole, and the
whole on the parts; which has its activity and _raison d’être_ within;
which manifests all the powers which we have described water to want;
and which requires for its continuance conditions of which water is
independent. It is only so far as organization and life are concerned,
however, that the cell is thus different from water. Chemically and
physically, as said, it can show with it quality for quality. How
strangely Mr. Huxley’s deliverances show beside these facts! He can “see
no break in the series of steps in molecular complication;” but,
glaringly obvious, there is a step added that is not molecular at all,
and that has its supporting conditions completely elsewhere. The
molecules are as fully accounted for in protoplasm as in water; but the
sum of qualities, thus exhausted in the latter, is not so exhausted in
the former, in which there are qualities due, plainly, not to the
molecules as molecules, but to the form into which they are thrown, and
the force that makes that form one. When the chemical elements are
brought together, Mr. Huxley says, protoplasm is formed, “and this
protoplasm exhibits the phenomena of life;” but he ought to have added
that these phenomena are themselves added to the phenomena for which all
that relates to chemistry stands, and are there, consequently, only by
reason of some other determinant. New consequents necessarily demand new
antecedents. “We think fit to call different kinds of matter carbon,
oxygen, hydrogen, and nitrogen, and to speak of the various powers and
activities of these substances as the properties of the matter of which
they are composed.” That, doubtless, is true, we say; but such
statements do not exhaust the facts. We call water hydrogen and oxygen,
and attribute _its_ properties to the properties of them. In a chemical
point of view, we ought to do the same thing for ice and steam; yet, for
all the chemical identity, water is not ice, nor is either steam. Do we,
then, in these cases, make nothing of the _difference_, and in its
despite enjoy the satisfaction of viewing the three as one? Not so; we
ask a reason for the difference; we demand an antecedent that shall
render the consequent intelligible. The chemistry of oxygen and hydrogen
is not enough in explanation of the threefold form; and by the very
necessity of the facts we are driven to the addition of heat. It is
precisely so with protoplasm in its twofold form. The chemistry
remaining the same in each (if it really does so), we are compelled to
seek elsewhere a reason for the difference of living from dead
protoplasm. As the differences of ice and steam from water lay not in
the hydrogen and oxygen, but in the heat, so the difference of living
from dead protoplasm lies not in the carbon, the hydrogen, the oxygen,
and the nitrogen, but in the vital organization. In all cases, for the
new quality, plainly, we must have a new explanation. The qualities of a
steam-engine are not the results of its simple chemistry. We do apply to
protoplasm the same conceptions, then, that are legitimate elsewhere,
and in allocating properties and explaining phenomena we simply insist
on Mr. Huxley’s own distinction of “living or dead.” That, in fact, is
to us the distinction of distinctions, and we admit no vital action
whatever, not even the dullest, to be the result of the _molecular_
action of the protoplasm that displays it. The very protoplasm of the
nettle-sting, with which Mr. Huxley begins, is already vitally
organized, and in that organization as much superior to its own
molecules as the steam-engine, in its mechanism, to its own wood and
iron. It were indeed as rational to say that there is no principle
concerned in a steam-engine or a watch but that of its molecular forces,
as to make this assertion of organized matter. Still there are degrees
in organization, and the highest forms of life are widely different from
the lowest. Degrees similar we see even in the inorganic world. The
persistent flow of a river is, to the mighty reason of the solar system,
in some such proportion, perhaps, as the rhizopod to man. In protoplasm,
even the lowest, then, but much more conspicuously in the highest, there
is, in addition to the molecular force, another force unsignalized by
Mr. Huxley—the force of vital organization.

But this force is a rational unity, and that is an idea; and this I
would point to as a second form of the addition to the chemistry and
physics of protoplasm. We have just seen, it is true, that an idea may
be found in inorganic matter, as in the solar and sidereal systems
generally. But the idea in organized matter is not one operative, so to
speak, from without: it is one operative from within, and in an
infinitely more intimate and pervading manner. The units that form the
complement of an inorganic system are but independently and externally
in place, like units in a procession; but in what is organized there is
no individual that is not sublated into the unity of the single life.
This is so even in protoplasm. Mr. Huxley, it is true, desiderates, as
result of mere ordinary chemical process, a life-stuff in mass, as it
were in the web, to which he has only to resort for cuttings and
cuttings in order to produce, by aggregation, what organized individual
he pleases. But the facts are not so: we cannot have protoplasm in the
web, but the piece. There is as yet no _matter_ of life; there are still
_cells_ of life. It is no shred of protoplasm—no spoonful or
toothpickful—that can be recognized as adequate to the function and the
name. Such shred may wriggle a moment, but it produces nought, and it
dies. In the smallest, lowest protoplasm-cell, then, we have this
rational unity of a complement of individuals that only are for the
whole and exist in the whole. This is an idea, therefore; this is
design: the organized concert of many to a single common purpose. The
rudest savage that should, as in Paley’s illustration, find a watch, and
should observe the various contrivances all controlled by the single end
in view, would be obliged to acknowledge—though in his own way—that what
he had before him was no mere physical, no mere molecular product. So in
protoplasm: even from the first, but, quite undeniably, in the completed
organization at last, which alone it was there to produce; for a single
idea has been its one manifestation throughout. And in what machinery
does it not at length issue? Was it molecular powers that invented a
respiration—that perforated the posterior ear to give a balance of
air—that compensated the _fenestra ovalis_ by a _fenestra rotunda_—that
placed in the auricular sacs those _otolithes_, those express stones for
hearing? Such machinery! The _chordæ tendineæ_ are to the valves of the
heart exactly adjusted check-strings; and the contractile _columnæ
carneæ_ are set in, under contraction and expansion, to equalize their
length to their office. Membranes, rods, and liquids—it required the
express experiment of man to make good the fact that the inventor of the
ear had availed himself of the most perfect apparatus possible for his
purpose. And are we to conceive such machinery, such apparatus, such
contrivances merely molecular? Are molecules adequate to such
things—molecules in their blind passivity, and dead, dull insensibility?
Is it to molecular agency Mr. Huxley himself owes that “singular inward
laboratory” of which he speaks, and without which all the protoplasm in
the world would be useless to him? Surely, in the presence of these
manifest ideas, it is impossible to attribute the single peculiar
feature of protoplasm—its vitality, namely—to mere molecular chemistry.
Protoplasm, it is true, breaks up into carbon, hydrogen, oxygen, and
nitrogen, as water does into hydrogen and oxygen; but the watch breaks
similarly up into mere brass, and steel, and glass. The loose materials
of the watch—even its chemical material if you will—replace its weight,
quite as accurately as the constituents carbon, etc., replace the weight
of the protoplasm. But neither these nor those replace the vanished
idea, which was alone the important element. Mr. Huxley saw no break in
the series of steps in molecular complication; but, though not
molecular, it is difficult to understand what more striding, what more
absolute break could be desired than the break into an idea. It is of
that break alone that we think in the watch; and it is of that break
alone that we should think in the protoplasm which, far more cunningly,
far more rationally, constructs a heart, an eye or an ear. That is the
break of breaks, and explain it as we may, we shall never explain it by
molecules.

But, if inorganic elements as such are inadequate to account either for
vital organization or the objective idea of design, much more are they
inadequate, in the third place, to account for the subjective idea, for
the phenomena of thought as thought. Yet Mr. Huxley tells us that
thought is but the expression of the molecular changes of protoplasm.
This he only tells us; this he does not prove. He merely says that, if
we admit the functions of the lowest forms of life to be but “direct
results of the nature of the matter of which they are composed,” we must
admit as much for the functions of the highest. We have not admitted Mr.
Huxley’s presupposition; but, even with its admission, we should not
feel bound to admit his conclusion. In such a mighty system of
differences, there are ample room and verge enough for the introduction
of new motives. We can say here at once, in fact, that as thought, let
its connection be what it may with, has never been proved to result
from, organization, no improvement of the proof required will be found
in protoplasm. No one power that Mr. Huxley signalizes in protoplasm can
account for thought: not alimentation, and not reproduction, certainly;
but not even contractility. We have seen already that there is no proof
of contraction being necessary even for the simplest sensation; but much
less is there any proof of a necessity of contraction for the inner and
independent operations of the mind. Mr. Huxley himself admits this. He
says: “Speech, gesture, and every other form of human action are, in the
long-run, resolvable into muscular contraction;” and so, “even those
manifestations of intellect, of feeling, and of will, which we rightly
name the higher faculties, are not excluded from this classification,
inasmuch as to every one _but the subject of them_, they are known only
as transitory changes in the relative positions of parts of the body.”
The concession is made here, we see that these manifestations are
differently known to the subject of them. But we may first object that,
if even that privileged “every one but the subject” were limited to a
knowledge of contractions, he would not know much. It is only because he
knows, first of all, a thinker and willer of contractions that these
themselves cease to be but passing externalities, and transitory
contingencies. Neither is it reasonable to assert an identity of nature
for contractions, and for that which they only represent. It would
hardly be fair to confound either the receiver or the sender of a
telegraphic message, with the movements which alone bore it, and without
which it would have been impossible. The sign is not the thing
signified, it is but the servant of the signifier—his own arbitrary
mark—and intelligible, in the first place, only to him. It is the
meaning, in all cases, that is alone vital; the sign is but an accident.
To convert the internality into the arbitrary externality that simply
expresses it, is for Mr. Huxley only an oversight. Your ideas are made
known to your neighbors by contractions, therefore your ideas are of the
same nature as contractions! Or, even to take it from the other side,
your neighbor perceives in you contractions only, and therefore your
ideas are contractions! Are not the vital elements here present the two
correspondent internalities, between which the contractions constitute
but an arbitrary chain of external communication, that is so now, but
may be otherwise again? The ringing of the bell at the window is not
precisely the dwarf within. Nor are Engineer Chappe’s “wooden arms and
elbow-joints jerking and fugling in the air,” to be identified with
Engineer Chappe himself. For the higher faculties, even for speech,
etc., assuredly Mr. Huxley might have well spared himself this
superfluous and inapplicable reference to contraction.

But, in the middle of it, as we have seen, Mr. Huxley concedes that
these manifestations are differently known to the subject of them. If
so, what becomes of his assertion of but a certain number of powers for
protoplasm? The manifestations of the higher faculties are not known to
the subject of them by contraction, etc. By what, then, are they known?
According to Mr. Huxley, they can only be known by the powers of
protoplasm; and therefore, by his own showing, protoplasm must possess
powers other than those of his own assertion. Mr. Huxley’s one great
power of contractility, Mr. Huxley himself confesses to be inapplicable
here. Indeed, in his Physiology (p. 193), he makes such an avowal as
this: “We class _sensations_, along with _emotions_, and _volitions_,
and _thoughts_, under the common head of states of _consciousness_; but
what consciousness is we know not, and how it is that anything so
remarkable as a state of consciousness comes about as the result of
irritating nervous tissue, is just as unaccountable as the appearance of
the Djin when Aladdin rubbed his lamp in the story.” Consciousness
plainly was not muscular contraction to Mr. Huxley when he wrote his
Physiology; it is only since then that he has gone over to the assertion
of no power in protoplasm but the triple power, contractility, etc. But
the truth is only as his Physiology has it—the cleft is simply, as Mr.
Huxley acknowledges it there, absolute. On one side, there is the world
of externality, where all is body by body, and away from one another—the
boundless reciprocal exclusion of the infinite object. On the other
side, there is the world of internality, where all is soul to soul, and
away into one another—the boundless reciprocal inclusion of the infinite
subject. This—even while it is true that, for subject to be subject, and
object, object, the boundless intussuscepted multiplicity of the single
invisible point of the one is but the dimensionless casket into which
the illimitable Genius of the other must retract and withdraw itself—is
the difference of differences; and certainly it is not internality that
can be abolished before externality. The proof for the absoluteness of
thought, the subject, the mind, is, on its side, pretty well perfect. It
is not necessary here, however, to enter into that proof at length.
Before passing on, I may simply point to the fact that, if thought is to
be called a function of matter, it must be acknowledged to be a function
wholly peculiar and unlike any other. In all other functions, we are
present to processes which are in the same sense physical as the organs
themselves. So it is with lung, stomach, liver, kidney, where every step
can be followed, so to speak, with eye and hand; but all is changed when
we have to do with mind as the function of brain. Then, indeed, as Mr.
Huxley thought in his Physiology, we are admitted, as if by touch of
Aladdin’s lamp, to a world absolutely different and essentially new—to a
world, on its side of the incommunicable cleft, as complete, entire,
independent, self-contained, and absolutely _sui generis_, as the world
of matter on the other side. It will be sufficient here to allude to as
much as this, with special reference to the fact that, so far as this
argument is concerned, protoplasm has not introduced any the very
slightest difference. All the ancient reasons for the independence of
thought as against organization, can be used with even more striking
effect as against protoplasm; but it will be sufficient to indicate
this, so much are the arguments in question a common property now.
Thought, in fact, brings with it its own warrant; or it brings with it,
to use the phrase of Burns, “its patent of nobility direct from Almighty
God.” And that is the strongest argument on this whole side. Throughout
the entire universe, organic and inorganic, thought is the controlling
sovereign; nor does matter anywhere refuse its allegiance. So it is in
thought, too, that man has _his_ patent of nobility, believes that he is
created in the image of God, and knows himself a free-man of infinitude.

But the analogy, in the hands of Mr. Huxley, has, we have seen, a second
reference—that, namely, to the excitants, if we may call them so, which
_determine_ combination. The _modus operandi_, Mr. Huxley tells us, of
preëxisting protoplasm in determining the formation of new protoplasm,
is not more unintelligible than the _modus operandi_ of the electric
spark in determining the formation of water; and so both, we are left to
infer, are perfectly analogous. The inferential turn here is rather a
favorite with Mr. Huxley. “But objectors of this class,” he says on an
earlier occasion, in allusion to those who hesitate to conclude from
dead to living matter, “do not seem to reflect that it is also, in
strictness, true that we know nothing about the composition of any body
whatever as it is.” In the same neighborhood, too, he argues that,
though impotent to restore to decomposed calc-spar its original form, we
do not hesitate to accept the chemical analysis assigned to it, and
should not, consequently, any more hesitate because of any mere
difference of form to accept the analysis of dead for that of living
protoplasm. It is certainly fair to point out that, if we bear ignorance
and impotence with equanimity in one case, we may equally so bear them
in another; but it is not fair to convert ignorance into knowledge, nor
impotence into power. Yet it is usual to take such statements loosely,
and let them pass. It is not considered that, if we know nothing about
the composition of any body whatever as it is, then we do know nothing,
and that it is strangely idle to offer absolute ignorance as a support
for the most dogmatic knowledge. If such statements are, as is really
expected for them, to be accepted, yet not accepted, they are the
stultification of all logic. Is the chemistry of living to be seen to be
the same as the chemistry of dead protoplasm, because we know nothing
about the composition of any body whatever as it is? We know perfectly
well that black is white, for we are absolutely ignorant of either as it
is! The _form_ of the calc-spar, which (the spar) we _can_ analyze, we
cannot restore; therefore the _form_ of the protoplasm, which we
_cannot_ analyze, has nothing to do with the matter in hand; and the
chemistry of what is dead may be accepted as the chemistry of what is
living! In the case of reasoning so irrelevant it is hardly worth while
referring to what concerns the forms themselves; that they are totally
incommensurable, that in all forms of calc-spar there is no question but
of what is physical, while in protoplasm the change of form is
introduction into an entire new world. As in these illustrations, so in
the case immediately before us. No appeal to ignorance in regard to
something else, the electric spark, should be allowed to transform
another ignorance, that of the action of preëxisting protoplasm, into
knowledge, here into _the_ knowledge that the two unknown things,
because of non-knowledge, are—perfectly analogous! That this analogy
does not exist—that the electric spark and preëxisting protoplasm are,
in their relative places, _not_ on the same chemical level—this is the
main point for us to see; and Mr. Huxley’s allusion to our ignorance
must not be allowed to blind us to it. Here we have in a glass vessel so
much hydrogen and oxygen, into which we discharge an electric spark, and
water is the result. Now what analogy is it possible to perceive between
this production of water by external experiment and the production of
protoplasm by protoplasm? The discrepancy is so palpable that it were
impertinent to enlarge on it. The truth is just this, that the measured
and mixed gases, the vessel, and the spark, in the one case, are as
unlike the fortuitous food, the living organs, and the long process of
assimilation in the other case, as the product water is unlike the
product protoplasm. No; that the action of the electric spark should be
unknown, is no reason why we should not insist on protoplasm for
protoplasm, on life for life. Protoplasm can only be produced by
protoplasm, and each of all the innumerable varieties of protoplasm,
only by its own kind. For the protoplasm of the worm we must go to the
worm, and for that of the toad-stool to the toad-stool. In fact, if all
living beings come from protoplasm, it is quite as certain that, but for
living beings, protoplasm would disappear. Without an egg you cannot
have a hen—that is true; but it is equally true that, without a hen, you
cannot have an egg. So in protoplasm; which, consequently, in the
production of itself, offers no analogy to the production, or
precipitation by the electric spark, not of itself, but of water.
Besides, if for protoplasm, preëxisting protoplasm, is always necessary,
how was there ever a first protoplasm?

Generally, then, Mr. Huxley’s analogy does not hold, whether in the one
reference or the other, and Mr. Huxley has no warrant for the reduction
of protoplasm to the mere chemical level which he assigns it in either.
That level is brought very prominently forward in such expressions as
these: That it is only necessary to bring the chemical elements
“together,” “under certain conditions,” to give rise to the more complex
body, protoplasm, just as there is a similar expedient to give rise to
water; and that, under the influence of preëxisting living protoplasm,
carbonic acid, water, and ammonia disappear, and an equivalent weight of
protoplasm makes its appearance, just as, under the influence of the
electric spark, hydrogen and oxygen disappear, and an equivalent weight
of water makes its appearance. All this, plainly, is to assume for
protoplasm such mere chemical place and nature as consist not with the
facts. The cases are, in truth, not parallel, and the “certain
conditions” are wholly diverse. All that is said we can do at will for
water, but nothing of what is said can we do at will for protoplasm. To
say we can feed protoplasm, and so make protoplasm at will produce
protoplasm, is very much, in the circumstances, only to say, and is not
to say, that, in this way, we make a chemical experiment. To insist on a
chemical analogy, in fact, between water and protoplasm, is to omit the
differences not covered by the analogy at all—thought, design, life, and
all the processes of organization; and it is but simple procedure to
omit these differences only by an appeal to ignorance elsewhere.

It is hardly worth while, perhaps, to refer now again to the
difference—here, however, once more incidentally suggested—between
protoplasm and protoplasm. Mr. Huxley, that is, almost in his very last
word on this part of the argument, seems to become aware of the bearing
of this on what relates to materiality, and he would again stamp
protoplasm (and with it life and intellect), into an indifferent
identity. In order that there should be no break between the lowest
functions and the highest (the functions of the fungus and the functions
of man), he has “endeavored to prove,” he says, that the protoplasm of
the lowest organisms is “essentially identical with, and most readily
converted into that of any animal.” On this alleged reciprocal
_convertibility_ of protoplasm, then, Mr. Huxley would again found as
well an inference of identity, as the further conclusion that the
functions of the highest, not less than those of the lowest animals, are
but the molecular manifestations of their common protoplasm.

Plainly here it is only the consideration, not of function, but of the
alleged reciprocal _convertibility_ that is left us now. Is this true,
then? Is it true that every organism can digest every other organism,
and that thus a relation of identity is established between that which
digests and whatever is digested? These questions place Mr. Huxley’s
general enterprise, perhaps, in the most glaring light yet; for it is
very evident that there is an end of the argument if all foods and all
feeders are essentially identical both with themselves and with each
other. The facts of the case, however, I believe to be too well known to
require a single word here on my part. It is not long since Mr. Huxley
himself pointed out the great difference between the foods of plants and
the foods of animals; and the reader may be safely left to think for
himself of _ruminantia_ and _carnivora_, of soft bills and hard bills,
of molluscs and men. Mr. Huxley talks feelingly of the possibility of
himself feeding the lobster quite as much as of the lobster feeding him;
but such pathos is not always applicable; it is not likely that a sponge
would be to the stomach of Mr. Huxley any more than Mr. Huxley to the
stomach of a sponge.

But a more important point is this, that the functions themselves remain
quite apart from the alleged convertibility. We can neither acquire the
functions of what we eat, nor impart our functions to what eats us. We
shall not come to fly by feeding on vultures, nor they to speak by
feeding on us. No possible manure of human brains will enable a
corn-field to reason. But if functions are inconvertible, the
convertibility of the protoplasm is idle. In this inconvertibility,
indeed, functions will be seen to be independent of mere chemical
composition. And that is the truth: for functions there is more required
than either chemistry or physics.

It is to be acknowledged—to notice one other incidental suggestion, for
the sake of completeness, and by way of transition to the final
consideration of possible objections—that Mr. Huxley would be very much
assisted in his identification of differences, were but the theories of
the molecularists, on the one hand, and of Mr. Darwin, on the other,
once for all established. The three modes of theorizing indicated,
indeed, are not without a tendency to approach one another; and it is
precisely their union that would secure a definitive triumph for the
doctrine of materialism. Mr. Huxley, as we have seen—though what he
desiderates is an auto-plastic living _matter_ that, produced by
ordinary chemical processes, is yet capable of continuing and developing
itself into new and higher forms—still begins with the egg. Now the
theory of the molecularists would, for its part, remove all the
difficulties that, for materialism, are involved in this beginning; it
would place protoplasm undeniably at length on a merely chemical level;
and would fairly enable Mr. Darwin, supplemented by such a life-stuff,
to account by natural means for everything like an idea or thought that
appears in creation. The misfortune is, however, that we must believe
the theory of the molecularists still to await the proof; while the
theory of Mr. Darwin has many difficulties peculiar to itself. This
theory, philosophically, or in ultimate analysis, is an attempt to prove
that design, or the objective idea, especially in the organic world, is
developed _in time_ by natural means. The time which Mr. Darwin demands,
it is true, is an infinite time; and he thus gains the advantage of his
processes being allowed greater _clearness_ for the understanding, in
consequence of the _obscurity_ of the infinite past in which they are
placed, and of which it is difficult in the first instance to deny any
possibility whatever. Still it remains to be asked, Are such processes
credible in any time? What Mr. Darwin has done in aid of his view is,
first, to lay before us a knowledge of facts in natural history of
surprising richness; and, second, to support this knowledge by an
inexhaustible ingenuity of hypothesis in arrangement of appearances.
Now, in both respects, whether for information or even interest, the
value of Mr. Darwin’s contribution will probably always remain
independent of the argument or arguments that might destroy his leading
proposition; and it is with this proposition that we have here alone to
do. As said, we ask only, Is it true that the objective idea, the design
which we see in the organized world, is the result in infinite time of
the necessary adaption of living structures to the peculiarities of the
conditions by which they are surrounded?

Against this theory, then, its own absolute generalization may be viewed
as our first objection. In ultimate abstraction, that is, the only
agency postulated by Mr. Darwin is time—infinite time; and as regards
actually existent beings and actually existent conditions, it is hardly
possible to deny any possibility whatever to infinitude. If told, for
example, that the elephant, if only obliged _infinitely_ to run, might
be converted into the stag, how should we be able to deny? So also, if
the lengthening of the giraffe’s neck were hypothetically attributed to
a succession of dearths in infinite time that only left the leaves of
trees for long-necked animals to live on, we should be similarly
situated as regards denial. Still it can be pointed out that ingenuity
of natural conjecture has, in such cases, no less wide a field for the
negation than for the affirmation; and that, on the question of fact,
nothing is capable of being determined. But we can also say more than
that—we can say that any fruitful application even of _infinite time_ to
the _general problem of difference_ in the world is inconceivable. To
explain all from an absolute beginning requires us to commence with
nothing; but to this nothing time itself is an addition. Time is an
entity, a something, a difference added to the original identity: whence
or how came time? Time cannot account for its own self; how is it that
there is such a thing as time? Then no conceivable brooding even of
infinite time could hatch the infinitude of space. How is it there is
such a thing as space? No possible clasps of time and space, further,
could ever conceivably thicken into matter. How is it there is such a
thing as matter? Lastly, so far, no conceivable brooding, or even
gyrating, of a single matter in time and space could account for the
specification of matter—carbon, gold, iodine, etc.—as we see and know
it. Time, space, matter, and the whole inorganic world, thus remain
impassive to the action even of infinite time; all _these_ differences
remain incapable of being accounted for so.

But suppose no curiosity had ever been felt in this reference, which,
though scientifically indefensible, is quite possible, how about the
transition of the inorganic into the organic? Mr. Huxley tells us that,
for food, the plant needs nothing but its bath of smelling-salts.
Suppose this bath now—a pool of a solution of carbonate of ammonia; can
any action of sun, or air, or electricity, be conceived to develop a
cell—or even so much lump-protoplasm—in this solution? The production of
an initial cell in any such manner will not allow itself to be realized
to thought. Then we have just to think for a moment of the vast
differences into which, for the production of the present organized
world, this cell must be distributed, to shake our heads and say we
cannot well refuse anything to an infinite time, but still we must
pronounce a problem of this reach hopeless.

It is precisely in conditions, however, that Mr. Darwin claims a
solution of this problem. Conditions concern all that relates to air,
heat, light, land, water, and whatever they imply. Our second objection,
consequently, is, that conditions are quite inadequate to account for
present organized differences, from a single cell. Geological time, for
example, falls short, after all, of infinite time; or, in known
geological eras, let us calculate them as liberally as we may, there is
not time enough to account for the presently-existing varieties, from
one, or even several, primordial forms. So to speak, it is not _in_
geological time to account for the transformation of the elephant into
the stag from acceleration, or for that of the stag into the elephant
from retardation, of movement. And we may speak similarly of the growth
of the neck of the giraffe, or even of the elevation of the monkey into
man. Moreover, time apart, conditions have no such power in themselves.
It is impossible to conceive of animal or vegetable effluvia ever
creating the nerve by which they are felt, and so gradually the
Schneiderian membrane, nose, and whole olfactory apparatus. Yet these
effluvia are the conditions of smell, and, _ex hypothesi_, ought to have
created it. Did light, or did the pulsations of the air, ever by any
length of time, indent into the sensitive cell, eyes, and a pair of
eyes—ears, and a pair of ears? Light conceivably might shine for ever
without such a wonderfully complicated result as an eye. Similarly, for
delicacy and marvellous ingenuity of structure, the ear is scarcely
inferior to the eye; and surely it is possible to think of a whole
infinitude of those fitful and fortuitous air-tremblings, which we call
sound, without indentation into anything whatever of such an organ.

A third objection to Mr. Darwin’s theory is, that the play of natural
contingency in regard to the vicissitudes of conditions, has no title to
be named _selection_. Naturalists have long known and spoken of the
“influence of accidental causes;” but Mr. Darwin was the first to apply
the term _selection_ to the action of these, and thus convert accident
into design. The agency to which Mr. Darwin attributes all the changes
which he would signalize in animals is really the fortuitous contingency
of brute nature; and it is altogether fallacious to call such process,
or such non-process, by a term involving foresight and a purpose. We
have here, indeed, only a metaphor wholly misapplied. The German writer
who, many years ago, said “even the _genera_ are wholly a prey to the
changes of the external universal life,” saw precisely what Mr. Darwin
sees, but it never struck him to style contingency selection. Yet, how
dangerous, how infectious, has not this ungrounded metaphor proved! It
has become a _principle_, a _law_, and been transferred by very genuine
men into their own sciences of philology and what not. People will
wonder at all this by-and-by. But to point out the inapplicability of
such a word to the processes of nature referred to by Mr. Darwin, is to
point out also the impossibility of any such contingencies proceeding,
by graduated rise, from stage to stage, into the great symmetrical
organic system—the vast plan—the grand harmonious whole—by which we are
surrounded. This rise, this system, is really the objective idea; but it
is utterly incapable of being accounted for by any such agency as
natural contingency in geological, or infinite, or any time. But it is
this which the word selection tends to conceal.

We may say, lastly, in objection, here, that, in the fact of “reversion”
or “atavism,” Mr. Darwin acknowledges his own failure. We thus see that
the species as species is something independent, and holds its own
_insita vis naturæ_ within itself.

Probably it is not his theory, then, that gives value to Mr. Darwin’s
book; nor even his ready ingenuity, whatever interest it may lend: it is
the material information it contains. The ingenuity, namely, verges
somewhat on that Humian expedient of natural conjecture so copiously
exemplified, on occasion of a few trite texts, in Mr. Buckle. But that
natural conjecture is always insecure, equivocal, and many-sided. It may
be said that ancient warfare, for example, giving victory always to the
personally ablest and bravest, must have resulted in the improvement of
the race; or that, the weakest being always necessarily left at home,
the improvement was balanced by deterioration; or that the ablest were
necessarily the most exposed to danger, and so, etc., etc., according,
to ingenuity _usque ad infinitum_. Trustworthy conclusion is not
possible to this method, but only to the induction of facts, or to
scientific demonstration.

Neither molecularists nor Darwinians, then, are able to level out the
difference between organic and inorganic, or between genera and genera
or species and species. The differences persist despite of both; the
distributed identity remains unaccounted for. Nor, consequently, is Mr.
Darwin’s theory competent to explain the objective idea by any reference
to time and conditions. Living beings do exist in a mighty chain from
the moss to the man; but that chain, far from founding, is founded in
the idea, and is not the result of any mere natural _growth_ of this
into that. That chain is itself the most brilliant stamp, the
sign-manual, of design. On every ledge of nature, from the lowest to the
highest, there is a life that is _its_,—a creature to represent it,
reflect it—so to speak, pasture on it. The last, highest, brightest link
of this chain is man; the incarnation of thought itself, which is the
summation of this universe; man, that includes in himself all other
links and their single secret—the personified universe, the subject of
the world. Mr. Huxley makes but small reference to thought; he only
tucks it in, as it were, as a mere appendicle of course.

It may be objected, indeed—to reach the last stage in this
discussion—that, if Mr. Huxley has not disproved the conception of
thought and life “as a something which works through matter, but is
independent of it,” neither have we proved it. But it is easy for us to
reply that, if “_independent of_” means here “_unconnected with_,” we
have had no such object. We have had no object whatever, in fact, but to
resist, now the extravagant assertion that all organized tissue, from
the lichen to Leibnitz, is alike in faculty, and again the equally
extravagant assertion that life and thought are but ordinary products of
molecular chemistry. As regards the latter assertion, we have endeavored
to show that the processes of vital organization (as self-production,
etc.) belong to another sphere, higher than, and very different from,
those of mechanical juxtaposition or chemical neutralization; that life,
then, is no mere product of matter as matter; that if no life can be
pointed to independent of matter, neither is there any life-stuff
independent of life; and that life, consequently, adds a new and higher
force to chemistry, as chemistry a new and higher force to mechanics,
etc. As for thought, the endeavor was to show that it was as independent
on the one side as matter on the other, that it controlled, used,
summed, and was the reason of matter. Thought, then, is not to be
reached by any bridge from matter, that is a hybrid of both, and
explains the connection. The relation of matter to mind is not to be
explained as a transition, but as a _contrecoup_. In this relation,
however, it is not the material, but the mental side, which the whole
universe declares to be the dominant one.

As regards any objection to the arguments which we have brought against
the identity of protoplasm, again, these will lie in the phrase,
probably, “difference not of kind, but degree,” or in the word
“modification.” The “phrase” may be now passed, for generic or specific
difference must be allowed in protoplasm, if not for the overwhelming
reason that an infinitude of various kinds exist in it, each of which is
self-productive and uninterchangeable with the rest, then for Mr.
Huxley’s own reason, that plants assimilate inorganic matter and animals
only organic. As for the objection “modification,” again, the same
consideration of generic difference must prove fatal to it. This were
otherwise, indeed, could but the molecularists and Mr. Darwin succeed in
destroying generic difference; but in this, as we have seen, they have
failed. And this will be always so: who dogs identity, difference dogs
him. It is quite a justifiable endeavor, for example, to point out the
identity that obtains between veins and arteries on the one hand, as
between these and capillaries on the other; but all the time the
difference is behind us; and when we turn to look, we see, for
circulation, the valves of the veins and the elastic coats of the
arteries as opposed to one another, and, for irrigation, the permeable
walls of the capillaries as opposed to both.

Generic differences exist then, and we cannot allow the word
“modification” to efface them in the interest of the identity claimed
for protoplasm. Brain-protoplasm is not bone-protoplasm, nor the
protoplasm of the fungus the protoplasm of man. Similarly, it is very
questionable how far the word “modification” will warrant us in
regarding with Mr. Huxley the “ducts, fibres, pollen, and ovules” of the
nettle as identical with the protoplasm of its sting. Things that
originate alike may surely eventuate in others which, chemically and
vitally, far from being mere modifications, must be pronounced totally
different. Such eventuation must be held competent to what can only be
named generic or specific difference. The “child” is only “_father_ of
the man”—it is not the man; who, moreover, in the course of an ordinary
life, we are told, has totally changed himself, not once, but many
times, retaining at the last not one single particle of matter with
which he set out. Such eventuations, whether called modifications or
not, certainly involve essential difference. And so situated are the
“ducts, fibres, pollen, and ovules” of the nettle, which, whether
compared with the protoplasm of the nettle-sting, or with that in which
they originated, must be held to here assumed, by their own actions,
indisputable differences, physical, chemical, and vital, or in form,
substance, and faculty.

Much, in fact, depends on definition here; and, in reference to
modification, it may be regarded as arbitrary when identity shall be
admitted to cease and difference to begin. There are the old Greek
puzzles of the Bald Head and the Heap, for example. How many grains, or
how many hairs, may we remove before a heap of wheat is no heap, or a
head of hair bald? These concern quantity alone; but, in other cases,
bone, muscle, brain, fungus, tree, man, there is not only a
quantitative, but a qualitative difference; and in regard to such
differences, the word modification can be regarded as but a cloak, under
which identity is to be shuffled into difference, but remain identity
all the same. The brick is but modified clay, Mr. Huxley intimates, bake
it and paint it as you may; but is the difference introduced by the
baking and painting to be ignored? Is what Mr. Huxley calls the
“artifice” not to be taken into account, leave alone the “potter?” The
strong firm rope is about as exact an example of modification
proper—modification of the weak loose hemp—as can well be found; but are
we to exclude from our consideration the whole element of difference due
to the hand and brain of man? Not far from Burn’s Monument, on the
Calton Hill of Edinburgh, there lies a mass of stones which is
potentially a church, the former Trinity College Church. Were this
church again realized, would it be fair to call it a mere modification
of the previous stones? Look now to the egg and the full-feathered fowl.
Chaucer describes to us the cock, “hight chaunteclere,” that was to his
“faire Pertelotte” so dear:—

            “His comb was redder than the fine corall,
             Embattled, as it were a castle-wall;
             His bill was black, and as the jet it shone;
             Like azure were his legges and his tone (toes);
             His nailes whiter than the lilie flour,
             And like the burned gold was his color.”

Would it be even as fair to call this fine fellow—comb, wattles, spurs,
and all—a modified yolk, as to call the church but modified stones? If,
in the latter case, an element of difference, altogether undeniable,
seems to have intervened, is not such intervention at least quite as
well marked in the former? It requires but a slight analysis to detect
that all the stones in question are marked and numbered; but will any
analysis point out within the shell the various parts that only need
arrangement to become the fowl? Are the men that may take the stones,
and, in a re-erected Trinity College Church, realize anew the idea of
its architect, in any respect more wonderful than the unknown disposers
of the materials of the fowl? That what realizes the idea should, in the
one case, be from without, and, in the other, from within, is no reason
for seeing more modification and less wonder in the latter than the
former. There is certainly no more reason for seeing the fowl in the
egg, and as identical with the egg, than for seeing a re-built Trinity
College Church as identical with its unarranged materials. A part cannot
be taken for the whole, whether in space _or in time_. Mr. Huxley misses
this. He is so absorbed in the identity out of which, that he will not
see the difference into which, progress is made. As the idea of the
church has the stones, so the idea of the fowl has the egg, for its
commencement. But to this idea, and in both cases, the terminal
additions belong, quite as much as the initial materials. If the idea,
then, add sulphur, phosphorus, iron, and what not, it must be credited
with these not less than with the carbon, hydrogen, etc., with which it
began. It is not fair to mutter modification, as if it were a charm to
destroy all the industry of time. The protoplasm of the egg of the fowl
is no more the fowl than the stones the church; and to identify, by
juggle of a mere word, parts in time and wholes in time so different, is
but self-deception. Nay, in protoplasm, as we have so often seen,
difference is as much present at first as at last. Even in its germ,
even in its initial identity, to call it so, protoplasm is already
different, for it issues in differences infinite.

Omission of the consideration of difference, it is to be acknowledged,
is not now-a-days restricted to Mr. Huxley. In the wonder that is
usually expressed, for example, at Oken’s _identification_ of the skull
with so many vertebræ, it is forgot that there is still implicated the
wonder which we ought to feel at the unknown power that could, in the
end, so _differentiate_ them. If the cornea of the eye and the enamel of
the teeth are alike but modified protoplasm, we must be pardoned for
thinking more of the adjective than of the substantive. Our wonder is
how, for one idea, protoplasm could become one thing here, and, for
another idea, another so different thing there. We are more curious
about the modification than the protoplasm. In the difference, rather
than in the identity, it is, indeed, that the wonder lies. Here are
several thousand pieces of protoplasm; analysis can detect no difference
in them. They are to us, let us say, as they are to Mr. Huxley,
identical in power, in form, and in substance; and yet on all these
several thousand little bits of apparently indistinguishable matter an
element of difference so pervading and so persistent has been impressed,
that, of them all, not one is interchangeable with another! Each seed
feeds its own kind. The protoplasm of the gnat will no more grow into
the fly than it will grow into an elephant. Protoplasm is protoplasm:
yes, but man’s protoplasm is man’s protoplasm, and the mushroom’s the
mushroom’s. In short, it is quite evident that the word modification, if
it would conceal, is powerless to withdraw, the difference; which
difference, moreover, is one of kind and not of degree.

This consideration of possible objections, then, is the last we have to
attend to; and it only remains to draw the general conclusion. All
animal and vegetable organisms are alike in power, in form, and in
substance, only if the protoplasm of which they are composed is
similarly alike; and the functions of all animal and vegetable organisms
are but properties of the molecular affections of their chemical
constituents, only if the functions of the protoplasm, of which they are
composed, are but properties of the molecular affections of _its_
chemical constituents. In disproof of the affirmative in both clauses,
there has been no object but to demonstrate, on the one hand, the
infinite non-identity of protoplasm, and, on the other, the dependence
of its functions upon other factors than its molecular constituents.

In short, the whole position of Mr. Huxley, that all organisms consist
alike of the same life-matter, which life-matter is, for its part, due
only to chemistry, must be pronounced untenable—nor less untenable the
materialism he would found on it.


------------------------------------------------------------------------




                   _ON THE HYPOTHESIS OF EVOLUTION_:

                       PHYSICAL AND METAPHYSICAL.




------------------------------------------------------------------------




                                 ON THE

                        HYPOTHESIS OF EVOLUTION:

                      _PHYSICAL AND METAPHYSICAL_.

“Man shall not live by bread alone, but by every word that proceedeth
    out of the mouth of God shall man live.” ch-hd-end There is
    apparently considerable repugnance in the minds of many excellent
    people to the acceptance, or even consideration, of the hypothesis
    of development, or that of the gradual creation by descent, with
    modification from the simplest beginnings, of the different forms of
    the organic world. This objection probably results from two
    considerations: first, that the human species is certainly involved,
    and man’s descent from an ape asserted; and, secondly, that the
    scheme in general seems to conflict with that presented by the
    Mosaic account of the Creation, which is regarded as communicated to
    its author by an infallible inspiration.

    As the truth of the hypothesis is held to be infinitely probable by
    a majority of the exponents of the natural sciences at the present
    day, and is held as absolutely demonstrated by another portion, it
    behooves those interested to restrain their condemnation, and on the
    other hand to examine its evidences, and look any consequent
    necessary modification of our metaphysical or theological views
    squarely in the face.

    The following pages state a few of the former; if they suggest some
    of the latter, it is hoped that they may be such as any logical mind
    would deduce from the premises. That they will coincide with the
    spirit of the most advanced Christianity, I have no doubt; and that
    they will add an appeal through the reason to that direct influence
    of the Divine Spirit which should control the motives of human
    action, seems an unavoidable conclusion.


                         I. PHYSICAL EVOLUTION.

    It is well known that a species is usually represented by a great
    number of individuals, distinguished from all other similar
    associations by more or less numerous points of structure, color,
    size, etc., and by habits and instincts also, to a certain extent;
    that the individuals of such associations reproduce their like, and
    cannot be produced by individuals of associations or species which
    present differences of structure, color, etc., as defined by
    naturalists; that the individuals of any such series or species are
    incapable of reproducing with those of any other species, with some
    exceptions; and that in the latter cases the offspring are usually
    entirely infertile.

    The hypothesis of Cuvier assumes that each species was created by
    Divine power as we now find it at some definite point of geologic
    time. The paleontologist holding this view sees, in accordance
    therewith, a succession of creations and destructions marking the
    history of life on our planet from its commencement.

    The development hypothesis states that all existing species have
    been derived from species of preëxistent geological periods, as
    offspring or by direct descent; that there have been no total
    destructions of life in past time, but only a transfer of it from
    place to place, owing to changes of circumstance; that the types of
    structure become simpler and more similar to each other as we trace
    them from later to earlier periods; and that finally we reach the
    simplest forms consistent with one or several original parent types
    of the great divisions into which living beings naturally fall.

    It is evident, therefore, that the hypothesis does not include
    change of species by hybridization, nor allow the descent of living
    species from any other _living_ species: both these propositions are
    errors of misapprehension or misrepresentation.

    In order to understand the history of creation of a complex being,
    it is necessary to analyze it and ascertain of what it consists. In
    analyzing the construction of an animal or plant we readily arrange
    its characters into those which it possesses in common with other
    animals or plants, and those in which it resembles none other: the
    latter are its _individual_ characters, constituting its
    individuality. Next we find a large body of characters, generally of
    a very obvious kind, which it possesses in common with a generally
    large number of individuals, which, taken collectively, all men are
    accustomed to call a species; these characters we consequently name
    _specific_. Thirdly, we find characters, generally in parts of the
    body which are of importance in the activities of the animal, or
    which lie in near relation to its mechanical construction in
    details, which are shared by a still larger number of individuals
    than those which were similar in specific characters. In other
    words, it is common to a large number of species. This kind of
    character we call _generic_, and the grouping it indicates is a
    genus.

    Farther analysis brings to light characters of organism which are
    common to a still greater number of individuals; this we call a
    _family_ character. Those which are common to still more numerous
    individuals are the _ordinal_: they are usually found in parts of
    the structure which have the closest connection with the whole
    life-history of the being. Finally, the individuals composing many
    orders will be found identical in some important character of the
    systems by which ordinary life is maintained, as in the nervous and
    circulatory: the divisions thus outlined are called _classes_.

    By this process of analysis we reach in our animal or plant those
    peculiarities which are common to the whole animal or vegetable
    kingdom, and then we have exhausted the structure so completely that
    we have nothing remaining to take into account beyond the
    cell-structure or homogeneous protoplasm by which we know that it is
    organic, and not a mineral.

    The history of the origin of a type, as species, genus, order, etc.,
    is simply the history of the origin of the structure or structures
    which define those groups respectively. It is nothing more nor less
    than this, whether a man or an insect be the object of
    investigation.


                        EVIDENCES OF DERIVATION.

                       α. Of Specific Characters.

    The evidences of derivation of species from species, within the
    limits of the genus, are abundant and conclusive. In the first
    place, the rule which naturalists observe in defining species is a
    clear consequence of such a state of things. It is not amount and
    degree of difference that determine the definition of species from
    species, but it is the _permanency_ of the characters in all cases
    and under all circumstances. Many species of the systems include
    varieties and extremes of form, etc., which, were they at all times
    distinct, and not connected by intermediate forms, would be
    estimated as species by the same and other writers, as can be easily
    seen by reference to their works.

    Thus, species are either “restricted” or “protean,” the latter
    embracing many, the former few variations; and the varieties
    included by the protean species are often as different from each
    other in their typical forms as are the “restricted” species. As an
    example, the species _Homo sapiens_ (man) will suffice. His primary
    varieties are as distinct as the species of many well-known genera,
    but cannot be defined, owing to the existence of innumerable
    intermediate forms between them.

    As to the common origin of such “varieties” of the protean species,
    naturalists never had any doubt, yet when it comes to the restricted
    “species,” the anti-developmentalist denies it _in toto_. Thus the
    varieties of most of the domesticated animals are some of them
    known—others held with great probability to have had a common
    origin. Varieties of plumage in fowls and canaries are of every-day
    occurrence, and are produced under our eyes. The cart-horse and
    racer, the Shetland pony and the Norman, are without doubt derived
    from the same parentage. The varieties of pigeons and ducks are of
    the same kind, but not every one is aware of the extent and amount
    of such variations. The varieties in many characters seen in hogs
    and cattle, especially when examples from distant countries are
    compared, are very striking, and are confessedly equal in degree to
    those found to _define_ species in a state of nature: here, however,
    they are not _definitive_.

    It is easy to see that all that is necessary to produce in the mind
    of the anti-developmentalist the illusion of distinct origin by
    creation of many of these forms, would be to destroy a number of the
    intermediate conditions of specific form and structure, and thus to
    leave remaining definable groups of individuals, and therefore
    “species.”

    That such destructions and extinctions have been going on ever since
    the existence of life on the globe is well known. That it should
    affect intermediate forms, such as bind together the types of a
    protean species as well as restricted species, is equally certain.
    That its result has been to produce _definable_ species cannot be
    denied, especially in consideration of the following facts: Protean
    species nearly always have a wide geographical distribution. They
    exist under more varied circumstances than do individuals of a more
    restricted species. The subordinate variations of the protean
    species are generally, like the restricted species, confined to
    distinct subdivisions of the geographical area which the whole
    occupies. As in geological time changes of level have separated
    areas once continuous by bodies of water or high mountain ranges, so
    have vast numbers of individuals occupying such areas been
    destroyed. Important alterations of temperature, or great changes in
    abundance or character of vegetable life over given areas, would
    produce the same result.

    This part of the subject might be prolonged, were it necessary, but
    it has been ably discussed by Darwin. The _rationale_ of the “origin
    of species” as stated by him may be examined a few pages farther on.

                 β. Of the Characters of Higher Groups.

    _a. Relations of Structures._ The evidences of derivative origin of
    the structures defining the groups called genera, and all those of
    higher grade, are of a very different character from those discussed
    in relation to specific characters; they are more difficult of
    observation and explanation.

    Firstly: It would appear to be supposed by many that the creation of
    organic types was an irregular and capricious process, variously
    pursued by its Author as regards time and place, and without
    definite final aim; and this notwithstanding the wonderful evidences
    we possess, in the facts of astronomy, chemistry, sound, etc., of
    His adhesion to harmonious and symmetrical sequences in His modes
    and plans.

    Such regularity of plan is found to exist in the relations of the
    great divisions of the animal and vegetable kingdoms as at present
    existing on the earth. Thus, with animals we have a great class of
    species which consists of nothing more than masses or cells of
    protoplasmic matter, without distinct organs; or the Protozoa. We
    have then the Cœlenterata (example, corals,) where the organism is
    composed of many cells arranged in distinct parts, but where a
    single very simple system of organs, forming the only internal
    cavity of the body, does the work of the many systems of the more
    complex animals. Next, the Echinodermata (such as star-fish) present
    us with a body containing distinct systems of organs enclosed in a
    visceral cavity, including a rudimental nervous system in the form
    of a ring. In the Molluscs to this condition is added additional
    complication, including extensions of the nervous system from the
    ring as a starting-point, and a special organ for a heart. In the
    Articulates (crabs, insects,) we have like complications, and a long
    distinct nervous axis on the lower surface of the body. The last
    branch or division of animals is considered to be higher, because
    all the systems of life organs are most complex or specialized. The
    nervous ring is almost obliterated by a great enlargement of its
    usual ganglia, thus become a brain, which is succeeded by a long
    axis on the upper side of the body. This and other points define the
    Vertebrata.

    Plans of structure, independent of the simplicity or perfection of
    the special arrangement or structure of organs, also define these
    great groups. Thus the Protozoa present a spiral, the Cœlenterata a
    radiate, the Echinodermata a bilateral radiate plan. The Articulates
    are a series of external rings, each in one or more respects
    repeating the others. The Molluscs are a sac, while a ring above a
    ring, joined together by a solid center-piece, represents the plan
    of each of the many segments of the Vertebrates which give the
    members of that branch their form.

    These bulwarks of distinction of animal types are entered into here
    simply because they are the most inviolable and radical of those
    with which we have to deal, and to give the anti-developmentalist
    the best foothold for his position. I will only allude to the
    relations of their points of approach, as these are affected by
    considerations afterward introduced.

    The Vertebrates approach the Molluscs at the lowest extreme of the
    former and higher of the latter. The lamprey eels of the one possess
    several characters in common with the cuttle-fish or squids of the
    latter. The amphioxus is called the lowest Vertebrate, and though it
    is nothing else, the definition of the division must be altered to
    receive it; it has no brain!

    The lowest forms of the Molluscs and Articulates are scarcely
    distinguishable from each other, so far as adhesion to the “plan” is
    concerned, and some of the latter division are very near certain
    Echinodermata. As we approach the boundary-lines of the two lowest
    divisions, the approaches become equally close, and the boundaries
    very obscure.

    More instructive is the evidence of the relation of the subordinate
    classes of any one of these divisions. The conditions of those
    organs or parts which define classes exhibit a regular relation,
    commencing with simplicity and ending with complication; first
    associated with weak exhibitions of the highest functions of the
    nervous system—at the last displaying the most exalted traits found
    in the series.

    For example: In the classes of Vertebrates we find the lowest
    nervous system presents great simplicity—the brain cannot be
    recognized; next (in lampreys), the end of the nervous axis is
    subdivided, but scarcely according to the complex type that follows.
    In fishes the cerebellum and cerebral hemispheres are minute, and
    the intermediate or optic lobes very large: in the reptiles the
    cerebral hemispheres exceed the optic lobes, while the cerebellum is
    smaller. In birds the cerebellum becomes complex and the cerebrum
    greatly increases. In mammals the cerebellum increases in complexity
    or number of parts, the optic lobes diminish, while the cerebral
    hemispheres become wonderfully complex and enlarged, bringing us to
    the highest development, in man.

    The history of the circulatory system in the Vertebrates is the
    same.[45] First, a heart with one chamber, then one with two
    divisions: three divisions belong to a large series, and the highest
    possess four. The origins of the great artery of the body, the
    aorta, are first five on each side: they lose one in the succeeding
    class in the ascending scale, and one in each succeeding class or
    order, till the Mammalia, including man, present us with but one on
    one side.

Footnote 45:

      See a homological system of the circulatory system in the author’s
      Origin of Genera, p. 22.

    From an infinitude of such considerations as the above, we derive
    the certainty that the general arrangement of the various groups of
    the organic world is in scales, the subordinate within the more
    comprehensive divisions. The identification of all the parts in such
    a complexity of organism as the highest animals present, is a matter
    requiring much care and attention, and constitutes the study of
    homologies. Its pursuit has resulted in the demonstration that every
    individual of every species of a given branch of the animal kingdom
    is composed of elements common to all, and that the differences
    which are so radical in the higher groups are but the modifications
    of the same elemental parts, representing completeness or
    incompleteness, obliteration or subdivision. Of the former character
    are rudimental organs, of which almost every species possesses an
    example in some part of its structure.

    But we have other and still more satisfactory evidence of the
    meaning of these relations. By the study of embryology we can prove
    most indubitably that the simple and less complex are inferior to
    the more complex. Selecting the Vertebrates again as an example, the
    highest form of mammal—_e.g._, man—presents in his earliest stages
    of embryonic growth a skeleton of cartilage, like that of the
    lamprey: he also possesses five origins of the aorta and five slits
    on the neck, both which characters belong to the lamprey and the
    shark. If the whole number of these parts does not coexist in the
    embryonic man, we find in embryos of lower forms more nearly related
    to the lamprey that they do. Later in the life of the mammal but
    four aortic origins are found, which arrangement, with the heart now
    divided into two chambers, from a beginning as a simple tube, is
    characteristic of the class of Vertebrates next in order—the bony
    fishes. The optic lobes of the human brain have also at this time a
    great predominance in size—a character above stated to be that of
    the same class. With advancing development the infant mammal follows
    the scale already pointed out. Three chambers of the heart and three
    aortic origins follow, presenting the condition permanent in the
    batrachia; and two origins, with enlarged cerebral hemispheres of
    the brain, resemble the reptilian condition. Four heart-chambers,
    and one aortic root on each side, with slight development of the
    cerebellum, follow all characters defining the crocodiles, and
    immediately precede the special conditions defining the mammals.
    These are, the single aorta root from one side, and the full
    development of the cerebellum: later comes that of the cerebrum also
    in its higher mammalian and human traits.

    Thus we see the order already pointed out to be true, and to be an
    ascending one. This is the more evident as each type or class passes
    through the conditions of those below it, as did the mammal; each
    scale being shorter as its highest terminus is lower. Thus the
    crocodile passes through the stage of the lamprey, the fish, the
    batrachian and the reptile proper.

    _b. In Time._ We have thus a scale of relations of existing forms of
    animals and plants of a remarkable kind, and such as to stimulate
    greatly our inquiries as to its significance. When we turn to the
    remains of the past creation preserved to us in the deposits
    continued throughout geologic time, we are not disappointed, for
    great light is at once thrown upon the subject.

    We find, in brief, that the lowest division of the animal kingdom
    appeared first, and long before any type of a higher character was
    created. The Protozoön, Eozoön, is the earliest of animals in
    geologic time, and represents the lowest type of animal life now
    existing. We learn also that the highest branch appeared last. No
    remains of Vertebrates have been found below the lower Devonian
    period, or not until the Echinoderms and Molluscs had reached a
    great preëminence. It is difficult to be sure whether the Protozoa
    had a greater numerical extent in the earliest periods than now, but
    there can be no doubt that the Cœlenterata (corals) and Echinoderms
    (crinoids) greatly exceeded their present bounds, in Paleozoic time,
    so that those at present existing are but a feeble remnant. If we
    examine the subdivisions known as classes, evidence of the nature of
    the succession of creation is still more conclusive. The most
    polyp-like of the Molluscs (brachiopoda) constituted the great mass
    of its representatives during Paleozoic time. Among Vertebrates the
    fishes appear first, and had their greatest development in size and
    numbers during the earliest periods of the existence of the
    division. Batrachia were much the largest and most important of land
    animals during the Carboniferous period, while the higher
    Vertebrates were unknown. The later Mesozoic periods saw the reign
    of reptiles, whose position in structural development has been
    already stated. Finally, the most perfect, the mammal, came upon the
    scene, and in his humblest representatives. In Tertiary times
    mammalia supplanted the reptiles entirely, and the unspiritual
    mammals now yield to man, the only one of his class in whom the
    Divine image appears.

    Thus the structural relations, the embryonic characters, and the
    successive appearance in time of animals coincide. The same is very
    probably true of plants.

    That the existing state of the geological record of organic types
    should be regarded as anything but a fragment is, from our
    stand-point, quite preposterous. And more, it may be assumed with
    safety that when completed it will furnish us with a series of
    regular successions, with but slight and regular interruptions, if
    any, from the species which represented the simplest beginnings of
    life at the dawn of creation, to those which have displayed
    complication and power in later or in the present period.

    For the labors of the paleontologist are daily bringing to light
    structures intermediate between those never before so connected, and
    thus creating lines of succession where before were only
    interruptions. Many such instances might be adduced: two may be
    selected as examples from American paleontology;[46] _i.e._, the
    near approach to birds made by the reptiles Lælaps and Megadactylus;
    and the combination of characters of the sub-orders of Cryptodire
    and Pleurodire Tortoises in the Adocus of New Jersey.

Footnote 46:

      Professor Huxley, in the last anniversary lecture before the
      Geological Society of London, recalls his opinion, enunciated in
      1862, that “the positively-ascertained truths of Paleontology”
      negative “the doctrines of progressive modification, which suppose
      that modification to have taken place by a necessary progress from
      more to less embryonic forms, from more to less generalized types,
      within the limits of the period represented by the fossiliferous
      rocks; that it shows no evidence of such modification; and as to
      the nature of that modification, it yields no evidence whatsoever
      that the earlier members of any long-continued group were more
      generalized in structure than the later ones.”

      Respecting this position, he says: “Thus far I have endeavored to
      expand and enforce by fresh arguments, but not to modify in any
      important respect, the ideas submitted to you on a former
      occasion. But when I come to the propositions respecting
      progressive modification, it appears to me, with the help of the
      new light which has broken from various quarters, that there is
      much ground for softening the somewhat Brutus-like severity with
      which I have dealt with a doctrine for the truth of which I should
      have been glad enough to be able to find a good foundation in
      1862. So far indeed as the Invertebrata and the lower Vertebrata
      are concerned, the facts, and the conclusions which are to be
      drawn from them, appear to me to remain what they were. For
      anything that as yet appears to the contrary, the earliest known
      marsupials may have been as highly organized as their living
      congeners; the Permian lizards show no signs of inferiority to
      those of the present day; the labyrinthodonts cannot be placed
      below the living salamander and triton; the Devonian ganoids are
      closely related to polypterus and lepidosiren.”

      To this it may be replied: 1. The scale of progression of the
      Vertebrata is measured by the conditions of the circulatory
      system, and in some measure by the nervous, and not by the
      osseous: tested by this scale, there has been successional
      complication of structure among Vertebrata in time. 2. The
      question with the evolutionist is, not what types have persisted
      to the present day, but the order in which types appeared in time.
      3. The Marsupials, Permian saurians, labyrinthodonts and Devonian
      ganoids are remarkably generalized groups, and predecessors of
      types widely separated in the present period. 4. Professor Huxley
      adduces many such examples among the mammalian subdivisions in the
      remaining portion of his lecture. 5. Two alternatives are yet open
      in the explanation of the process of evolution: since generalized
      types, which combine the characters of higher and lower groups of
      later periods, must thus be superior to the lower, the lower must
      (first) be descended from such a generalized form by degradation;
      or (second) not descended from it at all, but from some lower
      contemporaneous type by advance; the higher only of the two being
      derived from the first-mentioned. The last I suspect to be a true
      explanation, as it is in accordance with the homologous groups.
      This law will shorten the demands of paleontologists for time,
      since, instead of deriving all reptilia, batrachia, etc., from
      common origins, it points to the derivation of higher reptilia of
      a higher order from higher reptilia of a lower order, lower
      reptilia of the first from lower reptilia of the second; finally,
      the several groups of the lowest or most generalized order of
      reptilia from a parallel series of the class below, or batrachia.

    We had no more reason to look for intermediate or connecting forms
    between such types as these, than between any others of similar
    degree of remove from each other with which we are acquainted. And
    inasmuch as almost all groups, as genera, orders, etc., which are
    held to be distinct, but adjacent, present certain points of
    approximation to each other, the almost daily discovery of
    intermediate forms gives us confidence to believe that the pointings
    in other cases will also be realized.

                           γ. Of Transitions.

    The preceding statements were necessary to the comprehension of the
    supposed mode of metamorphosis or development of the various types
    of living beings, or, in other words, of the single structural
    features which define them.... As it is evident that the more
    comprehensive groups, or those of highest rank, have had their
    origin in remote ages, cases of transition from one to the other by
    change of character cannot be witnessed at the present day. We
    therefore look to the most nearly related divisions, or those of the
    lowest rank, for evidence of such change.

    It is necessary to premise that embryology teaches that all the
    species of a given branch of the animal kingdom (_e.g._, Vertebrate,
    Mollusc, etc.) are quite identical in structural character at their
    first appearance on the germinal layer of the yolk of the parent
    egg. It shows that the character of the respective groups of high
    rank appear first, then those of less grade, and last of all those
    structures which distinguish them as genera. But among the earliest
    characters which appear are those of the species, and some of those
    of the individual.

    We find the characters of different _genera_ to bear the same
    relation to each other that we have already seen in the case of
    those definitive of orders, etc. In a natural assemblage of related
    genera we discover that some are defined by characters found only in
    the embryonic stages of others; while a second will present a
    permanent condition of its definitive part, which marks a more
    advanced stage of that highest. In this manner many stages of the
    highest genus appear to be represented by permanent genera in all
    natural groups. Generally, however, this resemblance does not
    involve, an entire identity, there being some other immaturities
    found in the highest genus at the time it presents the character
    preserved in permanency by the lower, which the lower loses. Thus
    (to use a very coarse example) a frog at one stage of growth has
    four legs and a tail: the salamander always preserves four legs and
    a tail, thus resembling the young frog. The latter is, however, not
    a salamander at that time, because, among other things, the skeleton
    is represented by cartilage only, and the salamander’s is ossified.
    This relation is therefore an imitation only, and is called _inexact
    parallelism_.

    As we compare nearer and nearer relations—_i.e._, the genera which
    present fewest points of difference—we find the differences between
    undeveloped stages of the higher and permanent conditions of the
    lower to grow fewer and fewer, until we find numerous instances
    where the lower genus is exactly the same as the undeveloped stage
    of the higher. This relation is called that of _exact parallelism_.

    It must now be remembered that the permanence of a character is what
    gives it its value in defining genus, order, etc., in the eyes of
    the systematist. So long as the condition is permanent no transition
    can be seen: there is therefore no development. If the condition is
    transitional, it defines nothing, and nothing is developed; at
    least, so says the anti-developmentalist. It is the old story of the
    settler and the Indian: “Will you take owl and I take turkey, or I
    take turkey and you owl?”

    If we find a relation of _exact parallelism_ to exist between two
    sets of species in the condition of a certain organ, and the
    difference so expressed the only one which distinguishes them as
    sets from each other—if that condition is always the same in each
    set—we call them two genera: if in any species the condition is
    variable at maturity, or sometimes the undeveloped condition of the
    part is persistent and sometimes transitory, the sets characterized
    by this difference must be united by the systematist, and the whole
    is called a single genus.

    We know numerous cases where different individuals of the same
    species present this relation of _exact parallelism_ to each other;
    and as we ascribe common origin to the individuals of a species, we
    are assured that the condition of the inferior individual is, in
    this case, simply one of repressed growth, or a failure to fulfill
    the course accomplished by the highest. Thus, certain species of the
    salamandrine genus amblystoma undergo a metamorphosis involving
    several parts of the osseous and circulatory systems, etc., while
    half grown; others delay it till fully grown; one or two species
    remain indifferently unchanged or changed, and breed in either
    condition, while another species breeds unchanged, and has never
    been known to complete a metamorphosis.

    The nature of the relation of _exact parallelism_ is thus explained
    to be that of checked or advanced growth of individuals having a
    common origin. The relation of _inexact parallelism_ is readily
    explained as follows: With a case of _exact parallelism_ in the
    mind, let the repression producing the character of the lower,
    parallelize the latter with a stage of the former in which a second
    part is not quite mature: we will have a slight want of
    correspondence between the two. The lower will be immature in but
    one point, the incompleteness of the higher being seen in two
    points. If we suppose the immaturity to consist in a repression at a
    still earlier point in the history of the higher, the latter will be
    undeveloped in other points also: thus, the spike-horned deer of
    South America have the horn of the second year of the North American
    genus. They would be generically identical with that stage of the
    latter, were it not that these still possess their milk dentition at
    two years of age. In the same way the nature of the parallelisms
    seen in higher groups, as orders, etc., may be accounted for.

    The theory of homologous groups furnishes important evidence in
    favor of derivation. Many orders of animals (probably all, when we
    come to know them) are divisible into two or more sections, which I
    have called _homologous_. These are series of genera or families,
    which differ from each other by some marked character, but whose
    contained genera or families differ from each other in the same
    points of detail, and in fact correspond exactly. So striking is
    this correspondence that were it not for the general and common
    character separating the homologous series, they would be regarded
    as the same, each to each. Now it is remarkable that where studied
    the difference common to all the terms of two homologous groups is
    found to be one of _inexact parallelism_, which has been shown above
    to be evidence of descent. Homologous groups always occupy different
    geographical areas on the earth’s surface, and their relation is
    precisely that which holds between successive groups of life in the
    periods of geologic time.

    In a word, we learn from this source that distinct geologic epochs
    coexist at the same time on the earth. I have been forced to this
    conclusion[47] by a study of the structure of terrestrial life, and
    it has been remarkably confirmed by the results of recent deep-sea
    dredgings made by the United States Coast Survey in the Gulf Stream,
    and by the British naturalists in the North Atlantic. These have
    brought to light types of Tertiary life, and of even the still more
    ancient Cretaceous periods, living at the present day. That this
    discovery invalidates in any wise the conclusions of geology
    respecting lapse of time is an unwarranted assumption that some are
    forward to make. If it changes the views of some respecting the
    parallelism or coëxistence of faunæ in different regions of the
    earth, it is only the anti-developmentalists whose position must be
    changed.

Footnote 47:

      _Origin of Genera_, pages 70, 77, 79.

    For, if we find distinct geologic faunæ, or epochs defined by faunæ,
    coëxisting during the present period, and fading or emerging into
    one another as they do at their geographical boundaries, it is proof
    positive that the geologic epochs and periods of past ages had in
    like manner no trenchant boundaries, but also passed the one into
    the other. The assumption that the apparent interruptions are the
    result of transfer of life rather than destruction, or of want of
    opportunities of preservation, is no doubt the true one.

                      δ. Rationale of Development.

    _a. In Characters of Higher Groups._ It is evident in the case of
    the species in which there is an irregularity in the time of
    completion of metamorphosis that some individuals traverse a longer
    developmental line than those who remain more or less incomplete. As
    both accomplish growth in the same length of time, it is obvious
    that it proceeds with greater rapidity in one sense in that which
    accomplishes most: its growth is said to be accelerated. This
    phenomenon is especially common among insects, where the females of
    perfect males are sometimes larvæ or nearly so, or pupæ, or lack
    wings or some character of final development. Quite as frequently,
    some males assume characters in advance of others, sometimes in
    connection with a peculiar geographical range.

    In cases of _exact parallelism_ we reasonably suppose the cause to
    be the same, since the conditions are identical, as has been shown;
    that is, the higher conditions have been produced by a crowding back
    of the earlier characters and an acceleration of growth, so that a
    given succession in order of advance has extended over a longer
    range of growth than its predecessor in the same allotted time. That
    allotted time is the period before maturity and reproduction, and it
    is evident that as fast as modifications or characters should be
    assumed sufficiently in advance of that period, so certainly would
    they be conferred upon the offspring by reproduction. The
    _acceleration_ in the assumption of a character, progressing more
    rapidly than the same in another character, must soon produce, in a
    type whose stages were once the exact parallel of a permanent lower
    form, the condition of _inexact parallelism_. As all the more
    comprehensive groups present this relation to each other, we are
    compelled to believe that _acceleration_ has been the principle of
    their successive evolution during the long ages of geologic time.

    Each type has, however, its day of supremacy and perfection of
    organism, and a retrogression in these respects has succeeded. This
    has no doubt followed a law the reverse of acceleration, which has
    been called _retardation_. By the increasing slowness of the growth
    of the individuals of a genus, and later and later assumption of the
    characters of the latter, they would be successively lost.

    To what power shall we ascribe this acceleration, by which the first
    beginnings of structure have accumulated to themselves through the
    long geologic ages complication and power, till from the germ that
    was scarcely born into a sand-lance, a human being climbed the
    complete scale, and stood easily the chief of the whole?

    In the cases of species, where some individuals develop farther than
    others, we say the former possess more growth-force, or “vigor,”
    than the latter. We may therefore say that higher types of structure
    possess more “vigor” than the lower. This, however, we do not know
    to be true, nor can we readily find means to demonstrate it.

    The food which is taken by an adult animal is either assimilated, to
    be consumed in immediate activity of some kind, or stored for future
    use, and the excess is rejected from the body. We have no reason to
    suppose that the same kind of material could be made to subserve the
    production of life-force by any other means than that furnished by a
    living animal organism. The material from which this organism is
    constructed is derived first from the parent, and afterward from the
    food, etc., assimilated by the individual itself so long as growth
    continues. As it is the activity of assimilation directed to a
    special end during this latter period which we suppose to be
    increased in accelerated development, the acceleration is evidently
    not brought about by increased facilities for obtaining the means of
    life which the same individual possesses as an adult. That it is not
    in consequence of such increased facilities possessed by its parents
    over those of the type preceding it, seems equally improbable when
    we consider that the characters in which the parent’s advance has
    appeared are rarely of a nature to increase those facilities.

    The nearest approach to an explanation that can be offered appears
    to be somewhat in the following direction:

    There is every reason to believe that the character of the
    atmosphere has gradually changed during geologic time, and that
    various constituents of the mixture have been successively removed
    from it, and been stored in the solid material of the earth’s crust
    in a state of combination. Geological chemistry has shown that the
    cooling of the earth has been accompanied by the precipitation of
    many substances only gaseous at high temperatures. Hydrochloric and
    sulphuric acids have been transferred to mineral deposits or aqueous
    solutions. The removal of carbonic acid gas and the vapor of water
    has been a process of much slower progress, and after the expiration
    of all the ages a proportion of both yet remains. Evidence of the
    abundance of the former in the earliest periods is seen in the vast
    deposits of limestone rock; later, in the prodigious quantities of
    shells which have been elaborated from the same in solution. Proof
    of its abundance in the atmosphere in later periods is seen in the
    extensive deposits of coal of the Carboniferous, Triassic and
    Jurassic periods. If the most luxuriant vegetation of the present
    day takes but fifty tons of carbon from the atmosphere in a century,
    per acre, thus producing a layer over that extent of less than a
    third of an inch in thickness, what amount of carbon must be
    abstracted in order to produce strata of thirty-five feet in depth?
    No doubt it occupied a long period, but the atmosphere, thus
    deprived of a large proportion of carbonic acid, would in subsequent
    periods undoubtedly possess an improved capacity for the support of
    animal life.

    The successively higher degree of oxidization of the blood in the
    organs designed for that function, whether performing it in water or
    air, would certainly accelerate the performances of all the vital
    functions, and among others that of growth. Thus it may be that
    _acceleration_ can be accounted for, and the process of the
    development of the orders and sundry lesser groups of the Vertebrate
    kingdom indicated; for, as already pointed out, the definitions of
    such are radically placed in the different structures of the organs
    which aerate the blood and distribute it to its various
    destinations.

    But the great question, What determined the direction of this
    acceleration? remains unanswered. One cannot understand why more
    highly-oxidized blood should hasten the growth of partition of the
    ventricle of the heart in the serpent, the more perfectly to
    separate the aerated from the impure fluid; nor can we see why a
    more perfectly-constructed circulatory system, sending purer blood
    to the brain, should direct accelerated growth to the cerebellum or
    cerebral hemispheres in the crocodile.

    _b. In Characters of the Specific Kind._ Some of the characters
    usually placed in the specific category have been shown to be the
    same in kind as those of higher categories. The majority are,
    however, of a different kind, and have been discussed several pages
    back.

    The cause of the origin of these characters is shrouded in as much
    mystery as that of those which have occupied the pages immediately
    preceding. As in that case, we have to assume, as Darwin has done, a
    tendency in Nature to their production. This is what he terms “the
    principle of variation.” Against an unlimited variation the great
    law of heredity or atavism has ever been opposed, as a conservator
    and multiplier of type. This principle is exemplified in the fact
    that like produces like—that children are like their parents,
    frequently even in minutiæ. It may be compared to habit in
    metaphysical matters, or to that singular love of time or rhythm
    seen in man and lower animals, in both of which the tendency is to
    repeat in continual cycles a motion or state of the mind or sense.

    Further, but a proportion of the lines of variation is supposed to
    have been perpetuated, and the extinction of intermediate forms, as
    already stated, has left isolated groups or species.

    The effective cause of these extinctions is stated by Darwin to have
    been a “natural selection”—a proposition which distinguishes his
    theory from other development hypotheses, and which is stated in
    brief by the expression, “the preservation of the fittest.” Its
    meaning is this: that those characters appearing as results of this
    spontaneous variation which are little adapted to the conflict for
    subsistence, with the nature of the supply, or with rivals in its
    pursuit, dwindle and are sooner or later extirpated; while those
    which are adapted to their surroundings, and favored in the struggle
    for means of life and increase, predominate, and ultimately become
    the centers of new variation. “I am convinced,” says Darwin, “that
    natural selection has been the main, but not exclusive, means of
    modification.”

    That it has been to a large extent the means of preservation of
    those structures known as specific, must, I think, be admitted. They
    are related to their peculiar surroundings very closely, and are
    therefore more likely to exist under their influence. Thus, if a
    given genus extends its range over a continent, it is usually found
    to be represented by peculiar species—one in a maritime division,
    another in the desert, others in the forest, in the swamp or the
    elevated areas of the region. The wonderful interdependence shown by
    Darwin to exist between insects and plants in the fertilization of
    the latter, or between animals and their food-plants, would almost
    induce one to believe that it were the true expression of the whole
    law of development.

    But the following are serious objections to its universal
    application:

    First: The characters of the higher groups, from genera up, are
    rarely of a character to fit their possessors especially for
    surrounding circumstances; that is, the differences which separate
    genus from genus, order from order, etc., in the ascending scale of
    each, do not seem to present a superior adaptation to surrounding
    circumstances in the higher genus to that seen in the lower genus,
    etc. Hence, superior adaptation could scarcely have caused their
    selection above other forms not existing. Or, in other words, the
    different structures which indicate successional relation, or which
    measure the steps of progress, seem to be equally well fitted for
    the same surroundings.

    Second: The higher groups, as orders, classes, etc., have been in
    each geologic period alike distributed over the whole earth, under
    all the varied circumstances offered by climate and food. Their
    characters do not seem to have been modified in reference to these.
    Species, and often genera, are, on the other hand, eminently
    restricted according to climate, and consequently vegetable and
    animal food.

    The law of development which we seek is indeed not that which
    preserves the higher forms and rejects the lower after their
    creation, but that which explains why higher forms were created at
    all. Why in the results of a creation we see any relation of higher
    and lower, and not rather a world of distinct types, each perfectly
    adapted to its situation, but none properly higher than another in
    an ascending scale, is the primary question. Given the principle of
    advance, then natural selection has no doubt modified the details;
    but in the successive advances we can scarcely believe such a
    principle to be influential. _We look rather upon a progress as the
    result of the expenditure of some force fore-arranged for that end._

    It may become, then, a question whether in characters of high grade
    the habit or use is not rather the result of the acquisition of the
    structure than the structure the result of the encouragement offered
    to its assumed beginnings by use, or by liberal nutrition derived
    from the increasingly superior advantages it offers.

                     ε. The Physical Origin of Man.

    If the hypothesis here maintained be true, man is the descendant of
    some preëxistent generic type, the which, if it were now living, we
    would probably call an ape.

    Man and the chimpanzee were in Linnæus’ system only two species of
    the same genus, but a truer anatomy places them in separate genera
    and distinct families. There is no doubt, however, that Cuvier went
    much too far when he proposed to consider Homo as the representative
    of an order distinct from the quadrumana, under the name of bimana.
    The structural differences will not bear any such interpretation,
    and have not the same value as those distinguishing the orders of
    mammalia; as, for instance, between carnivora and bats, or the
    cloven-footed animals and the rodents, or rodents and edentates. The
    differences between man and the chimpanzee are, as Huxley well puts
    it, much less than those between the chimpanzee and lower
    quadrumana, as lemurs, etc. In fact, man is the type of a family,
    Hominidæ, of the order Quadrumana, as indicated by the characters of
    the dentition, extremities, brain, etc. The reader who may have any
    doubts on this score may read the dissections of Geoffroy St.
    Hilaire, made in 1856, before the issue of Darwin’s _Origin of
    Species_. He informs us that the brain of man is nearer in structure
    to that of the orang than the orang’s is to that of the South
    American howler, and that the orang and howler are more nearly
    related in this regard than are the howler and the marmoset.

    The modifications presented by man have, then, resulted from an
    acceleration in development in some respects, and retardation
    perhaps in others. But until the _combination_ now characteristic of
    the genus Homo was attained the being could not properly be called
    man.

    And here it must be observed that as an organic type is
    characterized by the coëxistence of a number of peculiarities which
    have been developed independently of each other, its distinctive
    features and striking functions are not exhibited until that
    coëxistence is attained which is necessary for these ends.

    Hence, the characters of the human genus were probably developed
    successively; but few of the indications of human superiority
    appeared until the combination was accomplished. Let the opposable
    thumb be first perfected, but of what use would it be in human
    affairs without a mind to direct? And of what use a mind without
    speech to unlock it? And speech could not be possible though all the
    muscles of the larynx but one were developed, or but a slight
    abnormal convexity in one pair of cartilages remained.

    It would be an objection of little weight could it be truly urged
    that there have as yet no remains of apelike men been discovered,
    for we have frequently been called upon in the course of
    paleontological discovery to bridge greater gaps than this, and
    greater remain, which we expect to fill. But we _have_ apelike
    characters exhibited by more than one race of men yet existing.

    But the remains of that being which is supposed to have been the
    progenitor of man may have been discovered a short time since in the
    cave of Naulette, Belgium, with the bones of the extinct rhinoceros
    and elephant.

    We all admit the existence of higher and lower races, the latter
    being those which we now find to present greater or less
    approximations to the apes. The peculiar structural characters that
    belong to the negro in his most typical form are of that kind,
    however great may be the distance of his remove therefrom. The
    flattening of the nose and prolongation of the jaws constitute such
    a resemblance; so are the deficiency of the calf of the leg, and the
    obliquity of the pelvis, which approaches more the horizontal
    position than it does in the Caucasian. The investigations made at
    Washington during the war with reference to the physical
    characteristics of the soldiers show that the arms of the negro are
    from one to two inches longer than those of the whites: another
    approximation to the ape. In fact, this race is a species of the
    genus Homo, as distinct in character from the Caucasian as those we
    are accustomed to recognize in other departments of the animal
    kingdom; but he is not distinct by isolation, since intermediate
    form’s between him and the other species can be abundantly found.

    And here let it be particularly observed that two of the most
    prominent characters of the negro are those of immature stages of
    the Indo-European race in its characteristic types. The deficient
    calf is the character of infants at a very early stage; but, what is
    more important, the flattened bridge of the nose and shortened nasal
    cartilages are universally immature conditions of the same parts in
    the Indo-European. Any one may convince himself of that by examining
    the physiognomies of infants. In some races—_e.g._, the Slavic—this
    undeveloped character persists later than in some others. The Greek
    nose, with its elevated bridge, coincides not only with æsthetic
    beauty, but with developmental perfection.

    This is, however, only “_inexact_ parallelism,” as the characters of
    the hair, etc., cannot be explained on this principle _among
    existing races_. The embryonic characters mentioned are probably a
    remnant of those characteristic of the primordial race or species.

    But the man of Naulette, if he be not a monstrosity, in a still more
    distinct and apelike species. The chin, that marked character of
    other species of men, is totally wanting, and the dentition is quite
    approximate to the man-like apes, and different from that of modern
    men. The form is very massive, as in apes. That he was not abnormal
    is rendered probable by approximate characters seen in a jaw from
    the cave of Puy-sur-Aube, and less marked in the lowest races of
    Australia and New Caledonia.

    As to the single or multiple origin of man, science as yet furnishes
    no answer. It is very probable that, in many cases, the species of
    one genus have descended from corresponding species of another by
    change of generic characters only. It is a remarkable fact that the
    orang possesses the peculiarly developed malar bones and the copper
    color characteristic of the Mongolian inhabitants of the regions in
    which this animal is found, while the gorilla exhibits the
    prognathic jaws and black hue of the African races near whom he
    dwells. This kind of geographical imitation is very common in the
    animal kingdom.

                         ζ. The Mosaic Account.

    As some persons imagine that this hypothesis conflicts with the
    account of the creation of man given in Genesis, a comparison of
    some of the points involved is made below.

    First: In Genesis i. 26, 27, we read, “And God said, Let us make man
    in our image, after our likeness,” etc. “So God created man in his
    own image, in the image of God created he him; male and female
    created he them.” Those who believe that this “image” is a physical,
    material form, are not disposed to admit the entrance of anything
    apelike into its constitution, for the ascription of any such
    appearance to the Creator would be impious and revolting. But we are
    told that “God is a Spirit,” and Christ said to his disciples after
    his resurrection, “A spirit hath not flesh and bones, as ye see me
    have.” Luke xxiv. 39. It will require little further argument to
    show that a mental and spiritual image is what is meant, as it is
    what truly exists. Man’s conscience, intelligence and creative
    ingenuity show that he possesses an “image of God” within him, the
    possession of which is really necessary to his limited comprehension
    of God and of God’s ways to man.

    Second: In Genesis ii. 7, the text reads, “And the Lord God formed
    man of the dust of the ground, and breathed into his nostrils the
    breath of life; and man became a living soul.” The fact that man is
    the result of the modification of an apelike predecessor nowise
    conflicts with the above statement as to the materials of which his
    body is composed. Independently of origin, if the body of man be
    composed of dust, so must that of the ape be, since the composition
    of the two is identical. But the statement simply asserts that man
    was created of the same materials which compose the earth: their
    condition as “dust” depending merely on temperature and subdivision.
    The declaration, “Dust thou art, and unto dust thou shalt return,”
    must be taken in a similar sense, for we know that the decaying body
    is resolved not only into its earthly constituents, but also into
    carbonic acid gas and water.

    When God breathed into man’s nostrils the breath of life, we are
    informed that he became, not a living body, but “a living soul.” His
    descent from a preëxistent being involved the possession of a living
    body; but when the Creator breathed into him we may suppose for the
    present that He infused into this body the immortal part, and at
    that moment man became a conscientious and responsible being.


                      II. METAPHYSICAL EVOLUTION.

    It is infinitely improbable that a being endowed with such
    capacities for gradual progress as man has exhibited, should have
    been full fledged in accomplishments at the moment when he could
    first claim his high title, and abandon that of his simious
    ancestors. We are therefore required to admit the growth of human
    intelligence from a primitive state of inactivity and absolute
    ignorance; including the development of one important mode of its
    expression—speech; as well as that of the moral qualities, and of
    man’s social system—the form in which his ideas of morality were
    first displayed.

    The expression “evolution of morality” need not offend, for the
    question in regard to the _laws_ of this evolution is the really
    important part of the discussion, and it is to the opposing views on
    this point that the most serious interest attaches.

                  *       *       *       *       *

    The two views of evolution already treated of, held separately, are
    quite opposed to each other. The first (and generally received) lays
    stress on the influence of external surroundings, as the stimulus to
    and guidance of development: it is the counterpart of Darwin’s
    principle called Natural Selection in material progress. This might
    be called the _Conflict theory_. The second view recognizes the
    workings of a force whose nature we do not know, whose exhibitions
    accord perfectly with their external surroundings (or other
    exhibitions of itself), without being under their influence or more
    related to them, as effect to cause, than the notes of the musical
    octave or the colors of the spectrum are to each other. This is the
    _Harmonic theory_. In other words, the first principle deduces
    perfection from struggle and discord; the second, from the
    coincident progress of many parts, forming together a divine harmony
    comparable to music. That these principles are both true is rendered
    extremely probable by the actual phenomena of development, material
    and immaterial. In other words, struggle and discord ever await that
    which is not in the advance, and which fails to keep pace with the
    harmonious development of the whole.

    All who have studied the phenomena of the creation believe that
    there exists in it a grand and noble harmony, such as was described
    to Job when he was told that “the morning stars sang together, and
    all the sons of God shouted for joy.”

                    α. Development of Intelligence.

    If the brain is the organ of mind, we may be surprised to find that
    the brain of the intelligent man scarcely differs in structure from
    that of the ape. Whence, then, the difference of power? Though no
    one will now deny that many of the Mammalia are capable of reasoning
    upon observed facts, yet how greatly the results of this capacity
    differ in number and importance from those achieved by human
    intelligence! Like water at the temperatures of 50° and 53°, where
    we perceive no difference in essential character, so between the
    brains of the lower and higher monkeys no difference of function or
    of intelligence is perceptible. But what a difference do the two
    degrees of temperature from 33° to 31° produce in water! In like
    manner the difference between the brain of the higher ape and that
    of man is accompanied by a difference in function and power, on
    which, man’s earthly destiny depends. In development, as with the
    water so with the higher ape: some Rubicon has been crossed, some
    floodgate has been opened, which marks one of Nature’s great
    transitions, such as have been called “Expression points” of
    progress.

    What point of progress in such a history would account for this
    accession of the powers of the human intelligence? It has been
    answered, with considerable confidence, The power of speech. Let us
    picture man without speech. Each generation would learn nothing from
    its predecessors. Whatever originality or observation might yield to
    a man would die with him. Each intellectual life would begin where
    every other life began, and would end at a point only differing with
    its original capacity. Concert of action, by which man’s power over
    the material world is maintained, would not exceed, if it equaled,
    that which is seen among the bees; and the material results of his
    labors would not extend beyond securing the means of life and the
    employment of the simplest modes of defence and attack.

    The first men, therefore, are looked upon by the developmentalists
    as extremely embryonic in all that characterizes humanity, and they
    appeal to the facts of history in support of this view. If they do
    not derive much assistance from written history, evidence is found
    in the more enduring relics of human handiwork.

    The opposing view is, that the races which present or have presented
    this condition of inferiority or savagery have reached it by a
    process of degradation from a higher state—as some believe, through
    moral delinquency. This position may be true in certain cases, which
    represent perhaps a condition of senility, but in general we believe
    that savagery was the condition of the first man, which has in some
    races continued to the present day.

                     _β. Evidence from Archæology._

    As the object of the present essay is not to examine fully into the
    evidences for the theories of evolution here stated, but rather to
    give a sketch of such theories and their connection, a few facts
    only will be noticed.

    _Improvement in the use of Materials._ As is well known, the remains
    of human handiwork of the earliest periods consist of nothing but
    rude implements of stone and bone, useful only in procuring food and
    preparing it for use. Even when enterprise extended beyond the
    ordinary routine, it was restrained by the want of proper
    instruments. Knives and other cutting implements of flint still
    attest the skill of the early races of men from Java to the Cape of
    Good Hope, from Egypt to Ireland, and through North and South
    America. Hatchets, spear-heads and ornaments of serpentine, granite,
    silex, clay slates, and all other suitable rock materials, are found
    to have been used by the first men, to the exclusion of metals, in
    most of the regions of the earth.

    Later, the probably accidental discovery of the superiority of some
    of the metals resulted in the substitution of them for stone as a
    material for cutting implements. Copper—the only metal which, while
    malleable, is hard enough to bear an imperfect edge—was used by
    succeeding races in the Old World and the New. Implements of this
    material are found scattered over extensive regions. So desirable,
    however, did the hardening of the material appear for the
    improvement of the cutting edge that combinations with other metals
    were sought for and discovered. The alloy with tin, forming bronze
    and brass, was discovered and used in Europe, while that with silver
    appears to have been most readily produced in America, and was
    consequently used by the Peruvians and other nations.

    The discovery of the modes of reducing iron ores placed in the hands
    of man the best material for bringing to a shape, convenient for his
    needs the raw material of the world. All improvements in this
    direction made since that time have been in the quality of iron
    itself, and not through the introduction of any new metal.

    The prevalent phenomena of any given period are those which give it
    its character, and by which we distinguish it. But this fact does
    not exclude the coëxistence of other phenomena belonging to prior or
    subsequent stages. Thus, during the many stages of human progress
    there have been men more or less in advance of the general body, and
    their characteristics have given a peculiar stamp to the later and
    higher condition of the whole. It furnishes no objection to this
    view that we find, as might have been anticipated, the stone, bronze
    and iron periods overlaping one another, or men of an inferior
    culture supplanting in some cases a superior people. A case of this
    kind is seen in North America, where the existing “Indians,”
    stone-men, have succeeded the mound-builders, copper-men. The
    successional relation of discoveries is all that it is necessary to
    prove, and this seems to be established.

    The period at which the use of metallic implements was introduced is
    unknown, but Whitney says that the language of the Aryans, the
    ancestors of all the modern Indo-Europeans, indicates an
    acquaintance with such implements, though it is not certain whether
    those of iron are to be included. The dispersion of the daughter
    races, the Hindoos, the Pelasgi, Teutons, Celts, etc., could not, it
    is thought, have taken place later than 3000 B. C.—a date seven
    hundred years prior, to that assigned by the old chronology to the
    Deluge. Those races coëxisted with the Egyptian and Chinese nations,
    already civilized, and as distinct from each other in feature as
    they are now.

    _Improvement in Architecture._ The earliest periods, then, were
    characterized by the utmost simplicity of invention and
    construction. Later, the efforts for defence from enemies and for
    architectural display, which have always employed so much time and
    power, began to be made. The megalithic period has left traces over
    much of the earth. The great masses of stone piled on each other in
    the simplest form in Southern India, and the circles of stones
    planted on end in England at Stonehenge and Abury, and in Peru at
    Sillustani, are relics of that period. More complex are the great
    Himyaritic walls of Arabia, the works of the ancestors of the
    Phœnicians in Asia Minor, and the titanic workmanship of the Pelasgi
    in Greece and Italy. In the iron age we find granitic hills shaped
    or excavated into temples; as, for example, everywhere in Southern
    India. Near Madura the circumference of an acropolis-like hill is
    cut into a series of statues in high relief, of sixty feet in
    elevation. Easter Island, composed of two volcanic cones, one
    thousand miles from the west coast of South America, in the bosom of
    the Pacific, possesses several colossi cut from the intrusive
    basalt, some in high relief on the face of the rock, others in
    detached blocks removed by human art from their original positions
    and brought nearer the sea-shore.

    Finally, at a more advanced stage, the more ornate and complex
    structures of Central America, of Cambodia, Nineveh and Egypt,
    represent the period of greatest display of architectural
    expenditure. The same amount of human force has perhaps never been
    expended in this direction since, though higher conceptions of
    beauty have been developed in architecture with increasing
    intellectuality.

    Man has passed through the block-and-brick building period of his
    boyhood, and should rise to higher conceptions of what is the true
    disposition of power for “him who builds for aye,” and learn that
    “spectacle” is often the unwilling friend of progress.

    No traces of metallic implements have ever been found in the
    salt-mines of Armenia, the turquoise-quarries in Arabia, the cities
    of Central America or the excavations for mica in North Carolina,
    while the direct evidence points to the conclusion that in those
    places flint was exclusively used.

    The simplest occupations, as requiring the least exercise of mind,
    are the pursuit of the chase and the tending of flocks and herds.
    Accordingly, we find our first parents engaged in these occupations.
    Cain, we are told, was, in addition, a tiller of the ground.
    Agriculture in its simplest forms requires but little more
    intelligence than the pursuits just mentioned, though no employment
    is capable of higher development. If we look at the savage nations
    at present occupying nearly half the land surface of the earth, we
    shall find many examples of the former industrial condition of our
    race preserved to the present day. Many of them had no knowledge of
    the use of metals until they obtained it from civilized men who
    visited them, while their pursuits were and are those of the chase,
    tending domestic animals, and rudimental agriculture.

                    γ. The Development of Language.

    In this department the fact of development from the simple to the
    complex has been so satisfactorily demonstrated by philologists as
    scarcely to require notice here. The course of that development has
    been from monosyllabic to polysyllabic forms, and also in a process
    of differentiation, as derivative races were broken off from the
    original stock and scattered widely apart. The evidence is clear
    that simple words for distinct objects formed the bases of the
    primal languages, just as the ground, tree, sun and moon represent
    the character of the first words the infant lisps. In this
    department also the facts point to an infancy of the human race.

                    δ. Development of the Fine Arts.

    If we look at representation by drawing or sculpture, we find that
    the efforts of the earliest races of which we have any knowledge
    were quite similar to those which the untaught hand of infancy
    traces on its slate or the savage depicts on the rocky faces of
    hills. The circle or triangle for the head and body, and straight
    lines for the limbs, have been preserved as the first attempts of
    the men of the stone period, as they are to this day the sole
    representations of the human form which the North American Indian
    places on his buffalo robe or mountain precipice. The stiff,
    barely-outlined form of the deer, the turtle, etc., are literally
    those of the infancy of civilized man.

    The first attempts at sculpture were marred by the influence of
    modism. Thus the idols of Coban and Palenque, with human faces of
    some merit, are overloaded with absurd ornament, and deformed into
    frightful asymmetry, in compliance with the demand of some imperious
    mode. In later days we have the stiff, conventionalized figures of
    the palaces of Nineveh and the temples of Egypt, where the
    representation of form has somewhat improved, but is too often
    distorted by false fashion or imitation of some unnatural standard,
    real or artistic. This is distinguished as the day of archaic
    sculpture, which disappeared with the Etruscan nation. So the
    drawings of the child, when he abandons the simple lines, are stiff
    and awkward, and but a stage nearer true representation; and how
    often does he repeat some peculiarity or absurdity of his own! So
    much easier is it to copy than to conceive.

    The introduction of the action and pose of life into sculpture was
    not known before the early days of Greece, and it was there that the
    art was brought to perfection. When art rose from its mediæval
    slumber, much the same succession of development may be discovered.
    First, the stiff figures, with straightened limbs and cylindric
    drapery, found in the old Northern churches—then the forms of life
    that now adorn the porticoes and palaces of the cities of Germany.

            ε. Rationale of the Development of Intelligence.

    The history of material development shows that the transition from
    stage to stage of development, experienced by the most perfect forms
    of animals and plants in their growth from the primordial cell, is
    similar to the succession of created beings which the geological
    epochs produced. It also shows that the slow assumption of main
    characters in the line of succession in early geological periods
    produced the condition of inferiority, while an increased rapidity
    of growth in later days has resulted in an attainment of
    superiority. It is not to be supposed that in “acceleration” the
    period of growth is shortened: on the contrary, it continues the
    same. Of two beings whose characters are assumed at the same rate of
    succession, that with the quickest or shortest growth is necessarily
    inferior. “Acceleration” means a gradual increase of the rate of
    assumption of successive characters in the same period of time. A
    fixed rate of assumption of characters, with gradual increase in the
    length of the period of growth, would produce the same result—viz.,
    a longer developmental scale and the attainment of an advanced
    position. The first is in part the relation of sexes of a species;
    the last of genera, and of other types of creation. If from an
    observed relation of many facts we derive a law, we are permitted,
    when we see in another class of facts similar relations, to suspect
    that a similar law has operated, differing only in its objects. We
    find a marked resemblance between the facts of structural progress
    in matter and the phenomena of intellectual and spiritual progress.

    If the facts entering into the categories enumerated in the
    preceding section bear us out, we conclude that in the beginning of
    human history the progress of the individual man was very slow, and
    that but little was attained to; that through the profitable
    direction of human energy, means were discovered from time to time
    by which the process of individual development in all metaphysical
    qualities has been accelerated; and that up to the present time the
    consequent advance of the whole race has been at an increasing rate
    of progress, This is in accordance with the general principle, that
    high development in intellectual things is accomplished by rapidity
    in traversing the preliminary stages of inferiority common to all,
    while low development signifies sluggishness in that progress, and a
    corresponding retention of inferiority.

    How much meaning may we not see, from this stand-point, in the
    history of the intelligence of our little ones! First they crawl,
    they walk on all fours: when they first assume the erect position
    they are generally speechless, and utter only inarticulate sounds.
    When they run about, stones and dirt, the objects that first meet
    the eye, are the delight of their awakening powers, but these are
    all cast aside when the boy obtains his first jackknife. Soon,
    however, reading and writing open a new world to him; and finally as
    a mature man he seizes the forces of nature, and steam and
    electricity do his bidding in the active pursuit of power for still
    better and higher ends.

    So with the history of the species: first the quadrumane—then the
    speaking man, whose humble industry was, however, confined to the
    objects that came first to hand, this being the “stone age” of
    pre-historic time. When the use of metals was discovered, the range
    of industries expanded wonderfully, and the “iron age” saw many
    striking efforts of human power. With the introduction of letters it
    became possible to record events and experiences, and the spread of
    knowledge was thereby greatly increased, and the delays and mistakes
    of ignorance correspondingly diminished in the fields of the world’s
    activity.

    From the first we see in history a slow advance as knowledge gained
    by the accumulation of tradition and by improvements in habit based
    on experience; but how slow was this advance while the use of the
    metals was still unknown! The iron age brought with it not only new
    conveniences, but increased means of future progress; and here we
    have an acceleration in the rate of advance. With the introduction
    of letters this rate was increased many fold, and in the application
    of steam we have a change equal in utility to any that has preceded
    it, and adding more than any to the possibilities of future advance
    in many directions. By its power, knowledge and means of happiness
    were to be distributed among the many.

    The uses to which human intelligence has successively applied the
    materials furnished by nature have been—First, subsistence and
    defence: second, the accumulation of power in the shape of a
    representative of that labor which the use of matter involves; in
    other words, the accumulation of wealth. The possession of this
    power involves new possibilities, for opportunity is offered for the
    special pursuits of knowledge and the assistance of the weak or
    undeveloped part of mankind in its struggles.

    Thus, while the first men possessed the power of speech, and could
    advance a little in knowledge through the accumulation of the
    experiences of their predecessors, they possessed no means of
    accumulating the power of labor, no control over the activity of
    numbers—in other words, no wealth.

    But the accumulation of knowledge finally brought this advance
    about. The extraction and utilization of the metals, especially
    iron, formed the most important step, since labor was thus
    facilitated and its productiveness increased in an incalculable
    degree. We have little evidence of the existence of a medium of
    exchange during the first or stone period, and no doubt barter was
    the only form of trade. Before the use of metals, shells and other
    objects were used: remains of money of baked clay have been found in
    Mexico. Finally, though in still ancient times, the possession of
    wealth in money gradually became possible and more common, and from
    that day to this avenues for reaching this stage in social progress
    has ever been opening.

    But wealth merely indicates a stage of progress, since it is but a
    comparative term. All men could not become rich, for in that case
    all would be equally poor. But labor has a still higher goal; for,
    thirdly, as capital, it constructs and employs machinery, which does
    the work of many hands, and thus cheapens products, which is
    equivalent in effect to an accumulation of wealth to the consumer.
    And this increase of power may be used for the intellectual and
    spiritual advance of men, or otherwise, at the will of the men thus
    favored. Machinery places man in the position of a creator,
    operating on Nature through an increased number of “secondary
    causes.”

    Development of intelligence is seen, then, in the following
    directions: First, in the knowledge of facts, including science;
    second, in language; third, in the apprehension of beauty; and, as
    consequences of the first of these, the accumulation of power by
    development—First, of means of subsistence; and second, of
    mechanical invention.

    Thus we have two terms to start with in estimating the beginning of
    human development in knowledge and power: First, the primary
    capacities of the human mind itself; second, a material world, whose
    infinitely varied components are so arranged as to yield results to
    the energies of that mind. For example, the transition points of
    vaporization and liquefaction are so placed as to be within the
    reach of man’s agents; their weights are so fixed as to accord with
    the muscular or other forces which he is able to exert; and other
    living organizations are subject to his convenience and rule, and
    not, as in previous geological periods, entirely beyond his control.
    These two terms being given, it is maintained that the present
    situation of the most civilized men has been attained through the
    operation of a law of mutual action and reaction—a law whose
    results, seen at the present time, have depended on the acceleration
    or retardation of its rate of action; which rate has been regulated,
    according to the degree in which a third great term, viz., the law
    of moral or (what is the same thing) true religious development has
    been combined in the plan. What it is necessary to establish in
    order to prove the above hypothesis is—

    I. That in each of the particulars above enumerated the development
    of the human species is similar to that of the individual from
    infancy to maturity.

    II. That from a condition of subserviency to the laws of matter,
    man’s intelligence enables him, by an accumulation of power, to
    become in a sense independent of those laws, and to increase greatly
    the rate of intellectual and spiritual progress.

    III. That failure to accomplish a moral or spiritual development
    will again reduce him to a subserviency to the laws of matter.

    This brings us to the subject of moral development. And here I may
    be allowed to suggest that the weight of the evidence is opposed to
    the philosophy, “falsely so called,” of necessitarianism, which
    asserts that the first two terms alone were sufficient to work out
    man’s salvation in this world and the next; and, on the other hand,
    to that anti-philosophy which asserts that all things in the
    progress of the human race, social and civil, are regulated by
    immediate Divine interposition instead of through instrumentalities.
    Hence the subject divides itself at once into two great
    departments—viz., that of the development of mind or intelligence,
    and that of the development of morality.

    That these laws are distinct there can be no doubt, since in the
    individual man one of them may produce results without the aid of
    the other. Yet it can be shown that each is the most invaluable aid
    and stimulant to the other, and most favorable to the rapid advance
    of the mind in either direction.


                  III. SPIRITUAL OR MORAL DEVELOPMENT.

    In examining this subject, we first inquire (Sect. _α_) whether
    there is any connection between physical and moral or religious
    development; then (_β_), what indications of moral development may
    be derived from history. Finally (_γ_), a correlation of the results
    of these inquiries, with the nature of the religious development in
    the individual, is attempted. Of course in so stupendous an inquiry
    but a few leading points can be presented here.

    If it be true that the period of human existence on the earth has
    seen a gradually increasing predominance of higher motives over
    lower ones among the mass of mankind, and if any parts of our
    metaphysical being have been derived by inheritance from preëxistent
    beings, we are incited to the inquiry whether any of the moral
    qualities are included among the latter; and whether there be any
    resemblance between moral and intellectual development.

    Thus, if there have been a physical derivation from a preëxistent
    genus, and an embryonic condition of those physical characters which
    distinguish Homo—if there has been also an embryonic or infantile
    stage in intellectual qualities—we are led to inquire whether the
    development of the individual in moral nature will furnish us with a
    standard of estimation of the successive conditions or present
    relations of the human species in this aspect also.

              _a. Relations of Physical and Moral Nature._

    Although men are much alike in the deeper qualities of their nature,
    there is a range of variation which is best understood by a
    consideration of the extremes of such variation, as seen in men of
    different latitudes, and women and children.

    (_a._) _In Children._ Youth is distinguished by a peculiarity, which
    no doubt depends upon an immature condition of the nervous center
    concerned, which might be called _nervous impressibility_. It is
    exhibited in a greater tendency to tearfulness, in timidity, less
    mental endurance, a greater facility in acquiring knowledge, and
    more ready susceptibility to the influence of sights, sounds and
    sensations. In both sexes the emotional nature predominates over the
    intelligence and judgment. In those years the _character_ is said to
    be in embryo, and theologians in using the phrase, “reaching years
    of religious understanding,” mean that in early years the religious
    _capacities_ undergo development coincidentally with those of the
    body.

    (_b._) _In Women._ If we examine the metaphysical characteristics of
    women, we observe two classes of traits—namely, those which are also
    found in men, and those which are absent or but weakly developed in
    men. Those of the first class are very similar in essential nature
    to those which men exhibit at an early stage of development. This
    may be in some way related to the fact that physical maturity occurs
    earlier in women.

    The gentler sex is characterized by a greater impressibility, often
    seen in the influence exercised by a stronger character, as well as
    by music, color or spectacle generally; warmth of emotion,
    submission to its influence rather than that of logic; timidity and
    irregularity of action in the outer world. All these qualities
    belong to the male sex, as a general rule, at some period of life,
    though different individuals lose them at very various periods.
    Ruggedness and sternness may rarely be developed in infancy, yet at
    some still prior time they certainly do not exist in any.

    Probably most men can recollect some early period of their lives
    when the emotional nature predominated—a time when emotion at the
    sight of suffering was more easily stirred than in maturer years. I
    do not now allude to the benevolence inspired, kept alive or
    developed by the influence of the Christian religion on the heart,
    but rather to that which belongs to the natural man. Perhaps all men
    can recall a period of youth when they were hero-worshipers—when
    they felt the need of a stronger arm, and loved to look up to the
    powerful friend who could sympathize with and aid them. This is the
    “woman stage” of character: in a large number of cases it is early
    passed; in some it lasts longer; while in a very few men it persists
    through life. Severe discipline and labor are unfavorable to its
    persistence. Luxury preserves its bad qualities without its good,
    while Christianity preserves its good elements without its bad.

    It is not designed to say that woman in her emotional nature does
    not differ from the undeveloped man. On the contrary, though she
    does not differ in kind, she differs greatly in degree, for her
    qualities grow with her growth, and exceed in _power_ many fold
    those exhibited by her companion at the original point of departure.
    Hence, since it might be said that man is the undeveloped woman, a
    word of explanation will be useful. Embryonic types abound in the
    fields of nature, but they are not therefore immature in the usual
    sense. Maintaining the lower essential quality, they yet exhibit the
    usual results of growth in individual characters; that is, increase
    of strength, powers of support and protection, size and beauty. In
    order to maintain that the masculine character coincides with that
    of the undeveloped woman, it would be necessary to show that the
    latter during her infancy possesses the male characters
    predominating—that is, unimpressibility, judgment, physical courage,
    and the like.

    If we look at the second class of female characters—namely, those
    which are imperfectly developed or absent in men, and in respect to
    which man may be called undeveloped woman—we note three prominent
    points: facility in language, tact or finesse, and the love of
    children. The first two appear to me to be altogether developed
    results of “impressibility,” already considered as an indication of
    immaturity. Imagination is also a quality of impressibility, and,
    associated with finesse, is apt to degenerate into duplicity and
    untruthfulness.

    The third quality is different. It generally appears at a very early
    period of life. Who does not know how soon the little girl selects
    the doll, and the boy the toy-horse or machine? Here man truly never
    gets beyond undeveloped woman. Nevertheless, “impressibility” seems
    to have a great deal to do with this quality also.

    Thus the metaphysical relation of the sexes would appear to be one
    of _inexact parallelism_, as defined in Sect. I. That the physical
    relation is a remote one of the same kind, several characters seem
    to point out. The case of the vocal organs will suffice. Their
    structure is identical in both sexes in early youth, and both
    produce nearly similar sounds. They remain in this condition in the
    woman, while they undergo a metamorphosis and change both in
    structure and vocal power in the man. In the same way, in many of
    the lower creation, the females possess a majority of embryonic
    features, though not invariably. A common example is to be found in
    the plumage of birds, where the females and young males are often
    undistinguishable.[48] But there are few points in the physical
    structure of man also in which the male condition is the immature
    one. In regard to structure, the point at which the relation between
    the sexes is that of _exact parallelism_, or where the mature
    condition of the one sex accords with the undeveloped condition of
    the other, is when reproduction is no longer accomplished by budding
    or gemmation, but requires distinct organs. Metaphysically, this
    relation is to be found where distinct individuality of the sexes
    first appears; that is, where we pass from the hermaphrodite to the
    bisexual condition.

Footnote 48:

      Meehan states that the upper limbs and strong laterals in coniferæ
      and other trees produce female flowers and cones, and the lower
      and more interior branches the male flowers. What he points out is
      in harmony with the position here maintained—namely, that the
      female characters include more of those which are embryonic in the
      males, than the male characters include of those which are
      embryonic in the female: the female flowers are the product of the
      younger and more growing portions of the tree—that is, those last
      produced (the upper limbs and new branches)—while the male flowers
      are produced by the older or more mature portions—that is, lower
      limbs or more axial regions.

      Meehan’s observations coincide with those of Thury and others on
      the origin of sexes in animals and plants, which it appears to
      admit of a similar explanation.

    But let us put the whole interpretation on this partial
    undevelopment of woman.

    The types or conditions of organic life which have been the most
    prominent in the world’s history—the Ganoids of the first, the
    Dinosaurs of the second, and the Mammoths of the third period—have
    generally died with their day. The line of succession has not been
    from them. The law of anatomy and paleontology is, that we must seek
    the point of departure of the type which is to predominate in the
    future, at lower stages on the line, in less decided forms, or in
    what, in scientific parlance, are called generalized types. In the
    same way, though the adults of the tailless apes are in a physical
    sense more highly developed than their young, yet the latter far
    more closely resemble the human species in their large facial angle
    and shortened jaws.

    How much significance, then, is added to the law uttered by
    Christ!—“Except ye become as little children, ye cannot enter the
    kingdom of heaven.” Submission of will, loving trust, confiding
    faith—these belong to the child: how strange they appear to the
    executing, commanding, reasoning man! Are they so strange to the
    woman? We all know the answer. Woman is nearer to the point of
    departure of that development which outlives time and peoples
    heaven; and if man would find it, he must retrace his steps, regain
    something he lost in youth, and join to the powers and energies of
    his character the submission, love and faith which the new birth
    alone can give.

    Thus the summing up of the metaphysical qualities of woman would be
    thus expressed: In the emotional world, man’s superior; in the moral
    world, his equal; in the laboring world, his inferior.

    There are, however, vast differences in women in respect to the
    number of masculine traits they may have assumed before being
    determined into their own special development. Woman also, under the
    influence of necessity, in later years of life, may add more or less
    to those qualities in her which are fully developed in the man.

    The relation of these facts to the principles stated as the two
    opposing laws of development is, it appears to me, to be explained
    thus: First, that woman’s most inherent peculiarities are _not_ the
    result of the external circumstances with which she has been placed
    in contact, as the _conflict theory_ would indicate. Such
    circumstances are said to be her involuntary subserviency to the
    physically more powerful man, and the effect of a compulsory mode of
    life in preventing her from attaining a position of equality in the
    activities of the world. Second, that they _are_ the result of the
    different distributions of qualities as already indicated by the
    _harmonic theory_ of development; that is, of the unequal possession
    of features which belong to different periods in the developmental
    succession of the highest. And here it might be further shown that
    this relation involves no disadvantage to either sex, but that the
    principle of compensation holds in moral organization and in social
    order, as elsewhere. There is then another beautiful harmony which
    will ever remain, let the development of each sex be extended as far
    as it may.

    (_c._) _In Men._ If we look at the male sex, we shall find various
    exceptional approximations to the female in mental constitution.
    Further, there can be little doubt that in the Indo-European race
    maturity in some respects appears earlier in tropical than in
    northern regions; and though subject to many exceptions, this is
    sufficiently general to be looked upon as a rule. Accordingly, we
    find in that race—at least in the warmer regions of Europe and
    America—a larger proportion of certain qualities which are more
    universal in women; as greater activity of the emotional nature when
    compared with the judgment; an impressibility of the nervous center,
    which, _cæteris paribus_, appreciates quickly the harmonies of
    sound, form and color; answers most quickly to the friendly greeting
    or the hostile menace; is more careless of consequences in the
    material expression of generosity or hatred, and more indifferent to
    truth under the influence of personal relations. The movements of
    the body and expressions of the countenance answer to the
    temperament. More of grace and elegance in the bearing mark the
    Greek, the Italian and the Creole, than the German, the Englishman
    or the Green Mountain man. More of vivacity and fire, for better or
    for worse, are displayed in the countenance.

    Perhaps the more northern type left all that behind in its youth.
    The rugged, angular character which appreciates force better than
    harmony, the strong intellect which delights in forethought and
    calculation, the less impressibility, reaching stolidity in the
    uneducated, are its well-known traits. If in such a character
    generosity is less prompt, and there is but little chivalry, there
    is persistency and unwavering fidelity, not readily interrupted by
    the lightning of passion or the dark surmises of an active
    imagination.

    All these peculiarities appear to result, _first_, from different
    degrees of quickness and depth in appreciating impressions from
    without; and, _second_, from differing degrees of attention to the
    intelligent judgment in consequent action. (I leave conscience out,
    as not belonging to the category of inherited qualities.)

    The first is the basis of an emotional nature, and the predominance
    of the second is the usual indication of maturity. That the first is
    largely dependent on an impressible condition of the nervous system
    can be asserted by those who reduce their nervous centers to a
    sensitive condition by a rapid consumption of the nutritive
    materials necessary to the production of thought-force, and perhaps
    of brain-tissue itself, induced by close and prolonged mental labor.
    The condition of over-work, though but an imitation of immaturity,
    without its joy-giving nutrition, is nevertheless very instructive.
    The sensitiveness, both physically, emotionally and morally, is
    often remarkable, and a weakening of the understanding is often
    coincident with it.

    It is necessary here to introduce a caution, that the meaning of the
    words high and low be not misunderstood. Great impressibility is an
    essential constituent of many of the highest forms of genius, and
    the combination of this quality with strong reflective intelligence,
    constitutes the most complete and efficient type of mind—therefore
    the highest in the common sense. It is not, however, the highest—or
    extremest—in an evolutional sense, it is not masculine, but
    hermaphrodite; in other words, its _kinetic_ force exceeds its
    _bathmic_.[49] It is therefore certain that a partial diminution of
    bathmic vigor is an advantage to some kinds of intellect.

Footnote 49:

      _Bathmic force_ is analogous to the _potential_ force of chemists,
      but is no doubt entirely different in its nature. It is converted
      into active energy or _kinetic_ force only during the years of
      growth: it is in large amount in _acceleration_, in small amount
      in _retardation_.

    The above observations have been confined to the Indo-European race.
    It may be objected to the theory that savagery means immaturity in
    the senses above described, as dependent largely on
    “impressibility,” while savages in general display the least
    “impressibility,” as that word is generally understood. This cannot
    be asserted of the Africans, who, so far as we know them, possess
    this peculiarity in a high degree. Moreover, it must be remembered
    that the state of indifference which precedes that of impressibility
    in the individual may characterize many savages; while their varied
    peculiarities may be largely accounted for by recollecting that many
    combinations of different species of emotions and kinds of
    intelligence go to make up the complete result in each case.

    (_d._) _Conclusions._ Three types of religion may be selected from
    the developmental conditions of man: first, an absence of
    sensibility (early infancy); second, an emotional stage more
    productive of faith than of works; thirdly, an intellectual type,
    more favorable to works than to faith. Though in regard to
    responsibility these states may be equal, there is absolutely no
    gain to laboring humanity from the first type, and a serious loss in
    actual results from the second, taken alone, as compared with the
    third.

    These, then, are the _physical vehicles of religion_—the “_earthen
    vessels_” of Paul—which give character and tone to the deeper
    spiritual life, as the color of the transparent vessel is
    communicated to the light which radiates from within.

    But if evolution has taken place, there is evidently a provision for
    the progress from the lower to the higher states, either in the
    education of circumstances (“conflict,”) or in the power of an
    interior spiritual influence “harmony,”) or both.

                  _β. Evidence Derived from History._

    We trace the development of Morality in—First, the family or social
    order; second, the civil order, or government.

    Whatever may have been the extent of moral ignorance before the
    Deluge, it does not appear that the earth was yet prepared for the
    permanent habitation of the human race. All nations preserve
    traditions of the drowning of the early peoples by floods, such as
    have occurred frequently during geologic time. At the close of each
    period of dry land, a period of submergence has set in, and the
    depression of the level of the earth, and consequent overflow by the
    sea, has caused the death and subsequent preservation of the remains
    of the fauna and flora living upon it, while the elevation of the
    same has produced that interruption in the process of deposit in the
    same region which marks the intervals between geologic periods.
    Change in these respects do not occur to any very material extent at
    the present time in the regions inhabited by the most highly
    developed portions of the human race; and as the last which occurred
    seems to have been expressly designed for the preparation of the
    earth’s surface for the occupation of organized human society, it
    may be doubted whether many such changes are to be looked for in the
    future. The last great flooding was that which stratified the drift
    materials of the north, and carried the finer portions far over the
    south, determining the minor topography of the surface and supplying
    it with soils.

    The existence of floods which drowned many races of men may be
    considered as established. The men destroyed by the one recorded by
    Moses are described by him as exceedingly wicked, so that “the earth
    was filled with violence.” In his eyes the Flood was designed for
    their extermination.

    That their condition was evil must be fully believed if they were
    condemned by the executive of the Jewish law. This law, it will be
    remembered, permitted polygamy, slavery, revenge, aggressive war.
    The Jews were expected to rob their neighbors the Egyptians of
    jewels, and they were allowed “an eye for an eye and a tooth for a
    tooth.” They were expected to butcher other nations, with their
    women and children, their flocks and their herds. If we look at the
    lives of men recorded in the Old Testament as examples of
    distinguished excellence, we find that their standard, however
    superior to that of the people around them, would ill accord with
    the morality of the present day. They were all polygamists,
    slaveholders and warriors. Abraham treated Hagar and Ishmael with
    inhumanity. Jacob, with his mother’s aid, deceived Isaac, and
    received thereby a blessing which extended to the whole Jewish
    nation. David, a man whom Paul tells us the Lord found to be after
    his own heart, slew the messenger who brought tidings of the death
    of Saul, and committed other acts which would stain the reputation
    of a Christian beyond redemption. It is scarcely necessary to turn
    to other nations if this be true of the chosen men of a chosen
    people. History indeed presents us with no people prior to, or
    contemporary with, the Jews who were not morally their inferiors.

    If we turn to more modern periods, an examination of the morality of
    Greece and Rome reveals a curious intermixture of lower and higher
    moral conditions. While each of these nations produced excellent
    moralists, the influence of their teachings was not sufficient to
    elevate the masses above what would now be regarded as a very low
    standard. The popularity of those scenes of cruelty, the
    gladiatorial shows and the combats with wild beasts, sufficiently
    attests this. The Roman virtue of patriotism, while productive of
    many noble deeds, is in itself far from being a disinterested one,
    but partakes rather of the nature of partisanship and selfishness.
    If the Greeks were superior to the Romans in humanity, they were
    apparently their inferiors in the social virtues, and were much
    below the standard of Christian nations in both respects.

    Ancient history points to a state of chronic war, in which the
    social relations were in confusion, and the development of the
    useful arts was almost impossible. Savage races, which continue to
    this day in a similar moral condition, are, we may easily believe,
    most unhappy. They are generally divided into tribes, which are
    mutually hostile, or friendly only with the view of injuring some
    other tribe. Might is their law, and robbery, rapine and murder
    express their mutual relations. This is the history of the lowest
    grade of barbarism, and the history of primeval man so far as it has
    come down to us in sacred and profane records. Man as a species
    first appears in history as a sinful being. Then a race maintaining
    a contest with the prevailing corruption and exhibiting a higher
    moral ideal is presented to us in Jewish history. Finally, early
    Christian society exhibits a greatly superior condition of things.
    In it polygamy scarcely existed, and slavery and war were condemned.
    But progress did not end here, for our Lord said, “I have yet many
    things to say unto you, _but ye cannot bear them now_. Howbeit, when
    He, the spirit of truth, is come, He will guide you into all truth.”

    The progress revealed to us by history is truly great, and if a
    similar difference existed between the first of the human species
    and the first of whose condition we have information, we can
    conceive how low the origin must have been. History begins with a
    considerable progress in civilization, and from this we must infer a
    long preceding period of human existence, such as a gradual
    evolution would require.

                   γ. Rationale of Moral Development.

    I. _Of the Species._ Let us now look at the moral condition of the
    infant man of the present time. We know his small accountability,
    his trust, his innocence. We know that he is free from the law that
    when he “would do good, evil is present with him,” for good and evil
    are alike unknown. We know that until growth has progressed to a
    certain degree he fully deserves the praise pronounced by Our
    Saviour, that “of such is the kingdom of heaven.” Growth, however,
    generally sees a change. We know that the buddings of evil appear
    but too soon: the lapse of a few months sees exhibitions of anger,
    disobedience, malice, falsehood, and their attendants—the fruit of a
    corruption within not manifested before.

    In early youth it may be said that moral susceptibility is often in
    inverse ratio to physical vigor. But with growth the more physically
    vigorous are often sooner taught the lessons of life, for their
    energy brings them into earlier conflict with the antagonisms and
    contradictions of the world. Here is a beautiful example of the
    benevolent principle of compensation.

    1. _Innocence and the Fall._ If physical evolution be a reality, we
    have reason to believe that the infantile stage of human morals, as
    well as of human intellect, was much prolonged in the history of our
    first parents. This constitutes the period of human purity, when we
    are told by Moses that the first pair dwelt in Eden. But the growth
    to maturity saw the development of all the qualities inherited from
    the irresponsible denizen of the forest. Man inherits from his
    predecessors in the creation the buddings of reason: he inherits
    passions, propensities and appetites. His corruption is that of his
    animal progenitors, and his sin is the low and bestial instinct of
    the brute creation. Thus only is the origin of sin made clear—a
    problem which the pride of man would have explained in any other way
    had it been possible.

    But how startling the exhibition of evil by this new being as
    compared with the scenes of the countless ages already past! Then
    the right of the strongest was God’s law, and rapine and destruction
    were the history of life. But into man had been “breathed the breath
    of life,” and he had “become a living soul.” The law of right, the
    Divine Spirit, was planted within him, and the laws of the beast
    were in antagonism to that law. The natural development of his
    inherited qualities necessarily brought him into collision with that
    higher standard planted within him, and that war was commenced which
    shall never cease “till He hath put all things under His feet.” The
    first act of man’s disobedience constituted the Fall, and with it
    would come the first _intellectual_ “knowledge of good and of
    evil”—an apprehension up to that time derived exclusively from the
    divinity within, or conscience.[50]

Footnote 50:

      In our present translation of Genesis, the Fall is ascribed to the
      influence of Satan assuming the form of the serpent, and this
      animal was cursed in consequence, and compelled to assume a prone
      position. This rendering may well be revised, since serpents,
      prone like others, existed in both America and Europe during the
      Eocene epoch, five times as great a period before Adam as has
      elapsed since his day. Clark states, with great probability, that
      “serpent” should be translated monkey or ape—a conclusion, it will
      be observed, exactly coinciding with our inductions on the basis
      of evolution. The instigation to evil by an ape merely states
      inheritance in another form. His curse, then, refers to the
      retention of the horizontal position by all other quadrumana, as
      we find it at the present day.

    2. _Free Agency._ Heretofore development had been that of physical
    types, but the Lord had rested on the seventh day, for man closed
    the line of the physical creation. Now a new development was to
    begin—the development of mind, of morality and of grace.

    On the previous days of Creation all had progressed in accordance
    with inevitable law apart from its objects. Now two lines of
    development were at the disposal of this being, between which his
    _free will_ was to choose. Did he choose the courses dictated by the
    spirit of the brute, he was to be subject to the old law of the
    brute creation—the right of the strongest and spiritual death. Did
    he choose the guidance of the Divine Guest in his heart, he became
    subject to the laws which are to guide—I. the human species to an
    ultimate perfection, so far as consistent with this world; and II.
    the individual man to a higher life, where a new existence awaits
    him as a spiritual being, freed from the laws of terrestrial matter.

    The charge brought against the theory of development, that it
    implies a necessary progress of man to all perfection without his
    coöperation—or _necessitarianism_, as it is called—is unfounded.

    The free will of man remains the source alike of his progress and
    his relapse. But the choice once made, the laws of spiritual
    development are apparently as inevitable as those of matter. Thus
    men whose religious capacities are increased by attention to the
    Divine Monitor within are in the advance of progress—progress
    coinciding with that which in material things is called the
    _harmonic_. On the other hand, those whose motives are of the lower
    origin fall under the working of the law of _conflict_.

    The lesson derivable from the preceding considerations would seem to
    be “necessitarian” as respects the whole human race, considered by
    itself; and I believe it is to be truly so interpreted. That is, the
    Creator of all things has set agencies at work which will slowly
    develop a perfect humanity out of His lower creation, and nothing
    can thwart the process or alter the result. “My word shall not
    return unto Me void, but it shall accomplish that which I please,
    and it shall prosper in the thing whereto I sent it.” This is our
    great encouragement, our noblest hope—second only to that which
    looks to a blessed inheritance in another world. It is this thought
    that should inspire the farmer, who as he toils wonders, “Why all
    this labor? The Good Father could have made me like the lilies, who,
    though they toil not, neither spin, are yet clothed in glory; and
    why should I, a nobler being, be subject to the dust and the sweat
    of labor?” This thought should enlighten every artisan of the
    thousands that people the factories and guide their whirling
    machinery in our modern cities. Every revolution of a wheel is
    moving the car of progress, and the timed stroke of the crank and
    the rhythmic throw of the shuttle are but the music the spheres have
    sung since time began. A new significance then appears in the prayer
    of David: “Let the beauty of the Lord our God be upon us, and
    establish Thou the work of our hands upon us: the work of our hands,
    O Lord, establish Thou it.” But beware of the catastrophe, for “He
    will sit as a refiner:” “the wheat shall be gathered into barns, but
    the chaff shall be burned with unquenchable fire.” If this be true,
    let us look for—

    3. _The Extinction of Evil._ How is necessitarianism to be
    reconciled with free will? It appears to me, thus: When a being
    whose safety depends on the perfection of a system of laws abandons
    the system by which he lives, he becomes subject to that lower grade
    of laws which govern lower intelligences. Man, falling from the laws
    of right, comes under the dominion of the laws of brute force; as
    said our Saviour: “Salt is good, but if the salt have lost his
    savor, it is thenceforth good for nothing but to be cast forth and
    trodden under foot of men.”

    Evil, being unsatisfying to the human heart, is in its nature ever
    progressive, whether in the individual or the nation; and in
    estimating the practical results to man of the actions prompted by
    the lower portion of our nature, it is only necessary to carry out
    to its full development each of those animal qualities which may in
    certain states of society be restrained by the social system. In
    human history those qualities have repeatedly had this development,
    and the battle of progress is fought to decide whether they shall
    overthrow the system that restrains them, or be overthrown by it.

    Entire obedience to the lower instincts of our nature ensures
    destruction to the weaker, and generally to the stronger also. A
    most marked case of this kind is seen where the developed vices of
    civilization are introduced among a savage people—as, for example,
    the North American Indians. These seem in consequence to be
    hastening to extinction.

    But a system or a circuit of existence has been allotted to the
    civil associations of the animal species man, independently of his
    moral development. It may be briefly stated thus: Races begin as
    poor offshoots or emigrants from a parent stock. The law of labor
    develops their powers, and increases their wealth and numbers. These
    will be diminished by their various vices; but on the whole, in
    proportion as the intellectual and economical elements prevail,
    wealth will increase; that is, they accumulate power. When this has
    been accomplished, and before activity has slackened its speed, the
    nation has reached the culminating point, and then it enters upon
    the period of decline. The restraints imposed by economy and active
    occupation being removed, the beastly traits find in accumulated
    power only increased means of gratification, and industry and
    prosperity sink together. Power is squandered, little is
    accumulated, and the nation goes down to its extinction amid scenes
    of internal strife and vice. Its cycle is soon fulfilled, and other
    nations, fresh from scenes of labor, assault it, absorb its
    fragments, and it dies. This has been the world’s history, and it
    remains to be seen whether the virtues of the nations now existing
    will be sufficient to save them from a like fate.

    Thus the history of the animal man in nations is wonderfully like
    that of the type or families of the animal and vegetable kingdoms
    during geologic ages. They rise, they increase and reach a period of
    multiplication and power. The force allotted to them becoming
    exhausted, they diminish and sink and die.

    II. _Of the Individual._ In discussing physical development, we are
    as yet compelled to restrict ourselves to the evidence of its
    existence and some laws observed in the operation of its causative
    force. What that force is, or what are its primary laws, we know
    not.

    So in the progress of moral development we endeavor to prove its
    existence and the mode of its operation, but why that mode should
    exist, rather than some other mode, we cannot explain.

    The moral progress of the species depends, of course, on the moral
    progress of the individuals embraced in it. Religion is the sum of
    those influences which determine the motives of men’s actions into
    harmony with the Divine perfection and the Divine will. Obedience to
    these influences constitutes the practice of religion, while the
    statement of the growth and operation of these influences
    constitutes the theory of religion, or doctrine.

    The Divine Spirit planted in man shows him that which is in harmony
    with the Divine Mind, and it remains for his free will to conform to
    it or reject it. This harmony is man’s highest ideal of happiness,
    and in seeking it, as well as in desiring to flee from dissonance or
    pain, he but obeys the disposition common to all conscious beings.
    If, however, he attempts to conform to it, he will find the law of
    evil present, and frequently obtaining the mastery. If now he be in
    any degree observing, he will find that the laws of morality and
    right are the only ones by which human society exists in a condition
    superior to that of the lower animals, and in which the capacities
    of man for happiness can approach a state of satisfaction. He may be
    then said to be “awakened” to the importance of religion. If he
    carry on the struggle to attain to the high goal presented to his
    spiritual vision, he will be deeply grieved and humbled at his
    failures: then he is said to be “convicted.” Under these
    circumstances the necessity of a deliverance becomes clear, and is
    willingly accepted in the only way in which it has pleased the
    Author of all to present it, which has been epitomized by Paul as
    “the washing of regeneration and renewal of the Holy Spirit through
    Jesus Christ.” Thus a life of advanced and ever-advancing moral
    excellence becomes possible, and the man makes nearer approaches to
    the “image of God.”

    Thus is opened a new era in spiritual development, which we are led
    to believe leads to an ultimate condition in which the nature
    inherited from our origin is entirely overcome, and an existence of
    moral perfection entered on. Thus in the book of Mark the simile
    occurs: “First the blade, then the ear, after that the full corn in
    the ear;” and Solomon says that the development of righteousness
    “shines more and more unto the perfect day.”

                              δ. Summary.

    If it be true that general development in morality proceeds in spite
    of the original predominance of evil in the world, through the
    self-destructive nature of the latter, it is only necessary to
    examine the reasons why the excellence of the good may have been
    subject also to progress, and how the remainder of the race may have
    been influenced thereby.

    The development of morality is then probably to be understood in the
    following sense: Since the Divine Spirit, as the prime force in
    moral progress, cannot in itself be supposed to have been in any way
    under the influence of natural laws, its capacities were no doubt as
    eternal and unerring in the first man as in the last. But the facts
    and probabilities discussed above point to development of _religious
    sensibility_, or capacity to appreciate moral good, or to receive
    impressions from the source of good.

    The evidence of this is supposed to be seen in—_First_, improvement
    in man’s views of his duty to his neighbor; and _Second_, the
    substitution of spiritual for symbolic religions: in other words,
    improvement in the capacity for receiving spiritual impressions.

    What the primary cause of this supposed development of religious
    sensibility may have been, is a question we reverently leave
    untouched. That it is intimately connected in some way with, and in
    part dependent on, the evolution of the intelligence, appears very
    probable: for this evolution is seen—_First_, in a better
    understanding of the consequences of action, and of good and of evil
    in many things; and _Second_, in the production of means for the
    spread of the special instrumentalities of good. The following may
    be enumerated as such instrumentalities:

    1. Furnishing literary means of record and distribution of the
    truths of religion, morality and science.

    2. Creating and increasing modes of transportation of teachers and
    literary means of disseminating truth.

    3. Facilitating the migration and the spread of nations holding the
    highest position in the scale of morality.

    4. The increase of wealth, which multiplies the extent of the
    preceding means.

    And now, let no man attempt to set bounds to this development. Let
    no man say even that morality accomplished is all that is required
    of mankind, since that is not necessarily the evidence of a
    spiritual development. If a man possess the capacity for progress
    beyond the condition in which he finds himself, in refusing to enter
    upon it he declines to conform to the Divine law. And “from those to
    whom little is given, little is required, but from those to whom
    much is given, much shall be required.”


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                          _SCIENTIFIC ADDRESSES._




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                          TYNDALL’S ADDRESSES.


                                   I.

       _On the Methods and Tendencies of Physical Investigation._

    The celebrated Fichte, in his lectures on the “Vocation of the
    Scholar,” insisted on a culture for the scholar which should not be
    one-sided, but all-sided. His intellectual nature was to expand
    spherically, and not in a single direction. In one direction,
    however, Fichte required that the scholar should apply himself
    directly to nature, become a creator of knowledge, and thus repay,
    by original labors of his own, the immense debt he owed to the
    labors of others. It was these which enabled him to supplement the
    knowledge derived from his own researches, so as to render his
    culture rounded, and not one-sided.

    Fichte’s idea is to some extent illustrated by the constitution and
    the labors of the British Association. We have here a body of men
    engaged in the pursuit of natural knowledge, but variously engaged.
    While sympathizing with each of its departments, and supplementing
    his culture by knowledge drawn from all of them, each student
    amongst us selects one subject for the exercise of his own original
    faculty—one line along which he may carry the light of his private
    intelligence a little way into the darkness by which all knowledge
    is surrounded. Thus, the geologist faces the rocks; the biologist
    fronts the conditions and phenomena of life; the astronomer, stellar
    masses and motions; the mathematician the properties of space and
    number; the chemist pursues his atoms, while the physical
    investigator has his own large field in optical, thermal,
    electrical, acoustical, and other phenomena. The British
    Association, then, faces nature on all sides, and pushes knowledge
    centrifugally outwards, while, through circumstance or natural bent,
    each of its working members takes up a certain line of research in
    which he aspires to be an original producer, being content in all
    other directions to accept instruction from his fellow-men. The sum
    of our labors constitutes what Fichte might call the sphere of
    natural knowledge. In the meetings of the Association it is found
    necessary to resolve this sphere into its component parts, which
    take concrete form under the respective letters of our sections.

    This section (A) is called the Mathematical and Physical section.
    Mathematics and Physics have been long accustomed to coalesce, and
    hence this grouping. For while mathematics, as a product of the
    human mind, is self-sustaining and nobly self-rewarding,—while the
    pure mathematician may never trouble his mind with considerations
    regarding the phenomena of the material universe, still the form of
    reasoning which he employs, the power which the organization of that
    reasoning confers, the applicability of his abstract conceptions to
    actual phenomena, render his science one of the most potent
    instruments in the solution of natural problems. Indeed, without
    mathematics, expressed or implied, our knowledge of physical science
    would be friable in the extreme.

    Side by side with the mathematical method, we have the method of
    experiment. Here, from a starting-point furnished by his own
    researches or those of others, the investigator proceeds by
    combining intuition and verification. He ponders the knowledge he
    possesses and tries to push it further, he guesses and checks his
    guess, he conjectures and confirms or explodes his conjecture. These
    guesses and conjectures are by no means leaps in the dark; for
    knowledge once gained casts a faint light beyond its own immediate
    boundaries. There is no discovery so limited as not to illuminate
    something beyond itself. The force of intellectual penetration into
    this penumbral region which surrounds actual knowledge is not
    dependent upon method, but is proportional to the genius of the
    investigator. There is, however, no genius so gifted as not to need
    control and verification. The profoundest minds know best that
    nature’s ways are not at all times their ways, and that the
    brightest flashes in the world of thought are incomplete until they
    have been proved to have their counterparts in the world of fact.
    The vocation of the true experimentalist is the incessant correction
    and realization of his insight; his experiments finally constituting
    a body, of which his purified intuitions are, as it were, the soul.

    Partly through mathematical, and partly through experimental
    research, physical science has of late years assumed a momentous
    position in the world. Both in a material and in an intellectual
    point of view it has produced, and it is destined to produce,
    immense changes, vast social ameliorations, and vast alterations in
    the popular conception of the origin, rule, and governance of
    things. Miracles are wrought by science in the physical world, while
    philosophy is forsaking its ancient metaphysical channels, and
    pursuing those opened or indicated by scientific research. This must
    become more and more the case as philosophic writers become more
    deeply imbued with the methods of science, better acquainted with
    the facts which scientific men have won, and with the great theories
    which they have elaborated.

    If you look at the face of a watch, you see the hour and
    minute-hands, and possibly also a second-hand, moving over the
    graduated dial. Why do these hands move, and why are their relative
    motions such as they are observed to be? These questions cannot be
    answered without opening the watch, mastering its various parts, and
    ascertaining their relationship to each other. When this is done, we
    find that the observed motion of the hands follows of necessity from
    the inner mechanism of the watch when acted upon by the force
    invested in the spring.

    This motion of the hands may be called a phenomenon of art, but the
    case is similar with the phenomena of Nature. These also have their
    inner mechanism, and their store of force to set that mechanism
    going. The ultimate problem of physical science is to reveal this
    mechanism, to discern this store, and to show that from the combined
    action of both, the phenomena of which they constitute the basis
    must of necessity flow.

    I thought that an attempt to give you even a brief and sketchy
    illustration of the manner in which scientific thinkers regard this
    problem would not be uninteresting to you on the present occasion;
    more especially as it will give me occasion to say a word or two on
    the tendencies and limits of modern science, to point out the region
    which men of science claim as their own, and where it is mere waste
    of time to oppose their advance, and also to define, if possible,
    the bourne between this and that other region to which the
    questionings and yearnings of the scientific intellect are directed
    in vain.

    But here your tolerance will be needed. It was the American Emerson,
    I think, who said that it is hardly possible to state any truth
    strongly without apparent injury to some other truth. Under the
    circumstances, the proper course appears to be to state both truths
    strongly, and allow each its fair share, in the formation of the
    resultant conviction. For truth is often of a dual character, taking
    the form of a magnet with two poles; and many of the differences
    which agitate the thinking part of mankind are to be traced to the
    exclusiveness with which different parties affirm one half of the
    duality in forgetfulness of the other half. But this waiting for the
    statement of the two sides of a question implies patience. It
    implies a resolution to suppress indignation if the statement of the
    one half should clash with our convictions, and not to suffer
    ourselves to be unduly elated if the half-statement should chime in
    with our views. It implies a determination to wait calmly for the
    statement of the whole before we pronounce judgment either in the
    form of acquiescence or dissent.

    This premised, let us enter upon our task. There have been writers
    who affirmed that the pyramids of Egypt were the productions of
    nature; and in his early youth Alexander Von Humboldt wrote an essay
    with the express object of refuting this notion. We now regard the
    pyramids as the work of men’s hands, aided probably by machinery of
    which no record remains. We picture to ourselves the swarming
    workers toiling at those vast erections, lifting the inert stones,
    and, guided by the volition, the skill, and possibly at times by the
    whip of the architect, placing the stones in their proper positions.
    The blocks in this case were moved by a power external to
    themselves, and the final form of the pyramid expressed the thought
    of its human builder.

    Let us pass from this illustration of building power to another of a
    different kind. When a solution of common salt is slowly evaporated,
    the water which holds the salt in solution disappears, but the salt
    itself remains behind. At a certain stage of concentration, the salt
    can no longer retain the liquid form; its particles, or molecules,
    as they are called, begin to deposit themselves as minute solids, so
    minute, indeed, as to defy all microscopic power. As evaporation
    continues solidification goes on, and we finally obtain, through the
    clustering together of innumerable molecules, a finite mass of salt
    of a definite form. What is this form? It sometimes seems a mimicry
    of the architecture of Egypt. We have little pyramids built by the
    salt, terrace above terrace from base to apex, forming thus a series
    of steps resembling those up which the Egyptian traveler is dragged
    by his guides. The human mind is as little disposed to look at these
    pyramidal salt-crystals without further question as to look at the
    pyramids of Egypt without inquiring whence they came. How, then, are
    those salt pyramids built up?

    Guided by analogy, you may suppose that, swarming among the
    constituent molecules of the salt, there is an invisible population,
    guided and coerced by some invisible master, and placing the atomic
    blocks in their positions. This, however, is not the scientific
    idea, nor do I think your good sense will accept it as a likely one.
    The scientific idea is that the molecules act upon each other
    without the intervention of slave labor; that they attract each
    other and repel each other at certain definite points, and in
    certain definite directions; and that the pyramidal form is the
    result of this play of attraction and repulsion. While, then, the
    blocks of Egypt were laid down by a power external to themselves,
    these molecular blocks of salt are self-posited, being fixed in
    their places by the forces with which they act upon each other.

    I take common salt as an illustration, because it is so familiar to
    us all; but almost any other substance would answer my purpose
    equally well. In fact, throughout inorganic nature, we have this
    formative power, as Fichte would call it—this structural energy
    ready to come into play, and build the ultimate particles of matter
    into definite shapes. It is present everywhere. The ice of our
    winters and of our polar regions is its hand-work, and so equally
    are the quartz, feldspar, and mica of our rocks. Our chalk-beds are
    for the most part composed of minute shells, which are also the
    product of structural energy; but behind the shell, as a whole, lies
    the result of another and more subtle formative act. These shells
    are built up of little crystals of calc-spar, and to form these the
    structural force had to deal with the intangible molecules of
    carbonate of lime. This tendency on the part of matter to organize
    itself, to grow into shape, to assume definite forms in obedience to
    the definite action of force, is, as I have said, all-pervading. It
    is in the ground on which you tread, in the water you drink, in the
    air you breathe. Incipient life, in fact, manifests itself
    throughout the whole of what we call inorganic nature.

    The forms of minerals resulting from this play of forces are
    various, and exhibit different degrees of complexity. Men of science
    avail themselves of all possible means of exploring this molecular
    architecture. For this purpose they employ in turn as agents of
    exploration, light, heat, magnetism, electricity, and sound.
    Polarized light is especially useful and powerful here. A beam of
    such light, when sent in among the molecules of a crystal, is acted
    on by them, and from this action we infer with more or less of
    clearness the manner in which the molecules are arranged. The
    difference, for example, between the inner structure of a plate of
    rock-salt and a plate of crystalized sugar or sugar-candy is thus
    strikingly revealed. These differences may be made to display
    themselves in phenomena of color of great splendor, the play of
    molecular force being so regulated as to remove certain of the
    colored constituents of white light, and to leave others with
    increased intensity behind.

    And now let us pass from what we are accustomed to regard as a dead
    mineral to a living grain of corn. When it is examined by polarized
    light, chromatic phenomena similar to those noticed in crystals are
    observed. And why? Because the architecture of the grain resembles
    in some degree the architecture of the crystal. In the corn the
    molecules are also set in definite positions, from which they act
    upon the light. But what has built together the molecules of the
    corn? I have already said, regarding crystalline architecture, that
    you may, if you please, consider the atoms and molecules to be
    placed in position by a power external to themselves. The same
    hypothesis is open to you now. But, if in the case of crystals you
    have rejected this notion of an external architect, I think you are
    bound to reject it now, and to conclude that the molecules of the
    corn are self-posited by the forces with which they act upon each
    other. It would be poor philosophy to invoke an external agent in
    the one case and to reject it in the other.

    Instead of cutting our grain into thin slices and subjecting it to
    the action of polarized light, let us place it in the earth and
    subject it to a certain degree of warmth. In other words, let the
    molecules, both of the corn and of the surrounding earth, be kept in
    a state of agitation; for warmth, as most of you know, is, in the
    eye of science, tremulous molecular motion. Under these
    circumstances, the grain and the substances which surround it
    interact, and a molecular architecture is the result of this
    interaction. A bud is formed; this bud reaches the surface, where it
    is exposed to the sun’s rays, which are also to be regarded as a
    kind of vibratory motion. And as the common motion of heat with
    which the grain and the substances surrounding it were first
    endowed, enable the grain and these substances to coalesce, so the
    specific motion of the sun’s rays now enables the green bud to feed
    upon the carbonic acid and the aqueous vapor of the air,
    appropriating those constituents of both for which the blade has an
    elective attraction, and permitting the other constituent to resume
    its place in the air. Thus forces are active at the root, forces are
    active in the blade, the matter of the earth and the matter of the
    atmosphere are drawn towards the plant, and the plant augments in
    size. We have in succession, the bud, the stalk, the ear, the full
    corn in the ear. For the forces here at play act in a cycle, which
    is completed by the production of grains similar to that with which
    the process began.

    Now there is nothing in this process which necessarily eludes the
    power of mind as we know it. An intellect the same kind as our own,
    would, if only sufficiently expanded, be able to follow the whole
    process from beginning to end. No entirely new intellectual faculty
    would be needed for this purpose. The duly expanded mind would see
    in the process and its consummation an instance of the play of
    molecular force. It would see every molecule placed in its position
    by the specific attractions and repulsions exerted between it and
    other molecules. Nay, given the grain and its environment, an
    intellect the same in kind as our own, but sufficiently expanded,
    might trace out _à priori_ every step of the process, and by the
    application of mechanical principles would be able to demonstrate
    that the cycle of actions must end, as it is seen to end, in the
    reproduction of forms like that with which the operation began. A
    similar necessity rules here to that which rules the planets in
    their circuits round the sun.

    You will notice that I am stating my truth strongly, as at the
    beginning we agreed it should be stated. But I must go still
    further, and affirm that in the eye of science the animal body is
    just as much the product of molecular force as the stalk and ear of
    corn, or as the crystal of salt or sugar. Many of its parts are
    obviously mechanical. Take the human heart, for example, with its
    exquisite system of valves, or take the eye or the hand. Animal
    heat, moreover, is the same in kind as the heat of a fire, being
    produced by the same chemical process. Animal motion, too, is as
    directly derived from the food of the animal, as the motion of
    Trevethyck’s walking-engine from the fuel in its furnace. As regards
    matter, the animal body creates nothing; as regards force, it
    creates nothing. Which of you by taking thought can add one cubit to
    his stature? All that has been said regarding the plant may be
    re-stated with regard to the animal. Every particle that enters into
    the composition of the muscle, a nerve, or a bone, has been placed
    in its position by molecular force. And unless the existence of law
    in these matters be denied, and the element of caprice be
    introduced, we must conclude that, given the relation of any
    molecule of the body to its environment, its position in the body
    might be predicted. Our difficulty is not with the quality of the
    problem, but with its complexity; and this difficulty might be met
    by the simple expansion of the faculties which man now possesses.
    Given this expansion, and given the necessary molecular data, and
    the chick might be deduced as rigorously and as logically from the
    egg as the existence of Neptune was deduced from the disturbances of
    Uranus, or as conical refraction was deduced from the undulatory
    theory of light.

    You see I am not mincing matters, but avowing nakedly what many
    scientific thinkers more or less distinctly believe. The formation
    of a crystal, a plant, or an animal, is in their eyes a purely
    mechanical problem, which differs from the problems of ordinary
    mechanics in the smallness of the masses and the complexity of the
    processes involved. Here you have one half of our dual truth; let us
    now glance at the other half. Associated with this wonderful
    mechanism of the animal body we have phenomena no less certain than
    those of physics, but between which and the mechanism we discern no
    necessary connection. A man, for example, can say I feel, I think, I
    love; but how does consciousness infuse itself into the problem? The
    human brain is said to be the organ of thought and feeling; when we
    are hurt the brain feels it, when we ponder it is the brain that
    thinks, when our passions or affections are excited it is through
    the instrumentality of the brain. Let us endeavor to be a little
    more precise here. I hardly imagine that any profound scientific
    thinker who has reflected upon the subject exists, who would not
    admit the extreme probability of the hypothesis, that for every fact
    of consciousness, whether in the domain of sense, of thought, or of
    emotion, a certain definite molecular condition is set up in the
    brain; that this relation of physics to consciousness is invariable,
    so that, given the state of the brain, the corresponding thought or
    feeling might be inferred; or, given the thought or feeling, the
    corresponding state of the brain might be inferred. But how
    inferred? It is at bottom not a case of logical inference at all,
    but of empirical association. You may reply that many of the
    inferences of science are of this character; the inference, for
    example, that an electric current of a given direction will deflect
    a magnetic needle in a definite way; but the cases differ in this,
    that the passage from the current to the needle, if not
    demonstrable, is thinkable, and that we entertain no doubt as to the
    final mechanical solution of the problem; but the passage from the
    physics of the brain to the corresponding facts of consciousness is
    unthinkable. Granted that a definite thought and a definite
    molecular action in the brain occur simultaneously, we do not
    possess the intellectual organ, nor, apparently, any rudiment of the
    organ, which would enable us to pass by a process of reasoning from
    the one phenomenon to the other. They appear together, but we do not
    know why. Were our minds and senses so expanded, strengthened, and
    illuminated as to enable us to see and feel the very molecules of
    the brain; were we capable of following all their motions, all their
    groupings, all their electric discharges, if such there be; and were
    we intimately acquainted with the corresponding states of thought
    and feeling, we should be as far as ever from the solution of the
    problem. “How are these physical processes connected with the facts
    of consciousness?” The chasm between the two classes of phenomena
    would still remain intellectually impassable. Let the consciousness
    of love, for example, be associated with a right-handed spiral
    motion of the molecules of the brain, and the consciousness of hate
    with a left-handed spiral motion. We should then know when we love
    that the motion is in one direction, and when we hate that the
    motion is in the other; but the “WHY?” would still remain
    unanswered.

    In affirming that the growth of the body is mechanical, and that
    thought, as exercised by us, has its correlative in the physics of
    the brain, I think the position of the “Materialist” is stated as
    far as that position is a tenable one. I think the materialist will
    be able finally to maintain this position against all attacks; but I
    do not think, as the human mind is at present constituted, that he
    can pass beyond it. I do not think he is entitled to say that his
    molecular groupings and his molecular motions explain everything. In
    reality they explain nothing. The utmost he can affirm is the
    association of two classes of phenomena of whose real bond of union
    he is in absolute ignorance. The problem of the connection of the
    body and soul is as insoluble in its modern form as it was in the
    pre-scientific ages. Phosphorus is known to enter into the
    composition of the human brain, and a courageous writer has
    exclaimed, in his trenchant German, “Ohne phosphor kein gedanke.”
    That may or may not be the case; but even if we knew it to be the
    case, the knowledge would not lighten our darkness. On both sides of
    the zone here assigned to the materialist he is equally helpless. If
    you ask him whence is this “matter” of which we have been
    discoursing, who or what divided it into molecules, who or what
    impressed upon them this necessity of running into organic forms, he
    has no answer. Science also is mute in reply to these questions. But
    if the materialist is confounded, and science rendered dumb, who
    else is entitled to answer? To whom has the secret been revealed?
    Let us lower our heads and acknowledge our ignorance, one and all.
    Perhaps the mystery may resolve itself into knowledge at some future
    day. The process of things upon this earth has been one of
    amelioration. It is a long way from the Iguanodon and his
    contemporaries to the president and members of the British
    Association. And whether we regard the improvement from the
    scientific or from the theological point of view as the result of
    progressive development, or as the result of successive exhibitions
    of creative energy, neither view entitles us to assume that man’s
    present faculties end the series—that the process of amelioration
    stops at him. A time may therefore come when this ultra-scientific
    region by which we are now enfolded may offer itself to terrestrial,
    if not to human investigation. Two-thirds of the rays emitted by the
    sun fail to arouse in the eye the sense of vision. The rays exist,
    but the visual organ requisite for their translation into light does
    not exist. And so from this region of darkness and mystery which
    surrounds us, rays may now be darting which require but the
    development of the proper intellectual organs to translate them into
    knowledge as far surpassing ours as ours does that of the wallowing
    reptiles which once held possession of this planet. Meanwhile the
    mystery is not without its uses. It certainly may be made a power in
    the human soul; but it is a power which has feeling, not knowledge,
    for its base. It may be, and will be, and we hope is turned to
    account, both in steadying and strengthening the intellect, and in
    rescuing man from that littleness to which, in the struggle for
    existence or for precedence in the world, he is continually prone.

                                  II.

                           On Haze and Dust.

    Solar light in passing through a dark room reveals its track by
    illuminating the dust floating in the air. “The sun,” says Daniel
    Culverwell, “discovers atomes, though they be invisible by
    candle-light, and makes them dance naked in his beams.”

    In my researches on the decomposition of vapors by light, I was
    compelled to remove these “atomes” and this dust. It was essential
    that the space containing the vapors should embrace no visible
    thing; that no substance capable of scattering the light in the
    slightest sensible degree should, at the outset of an experiment, be
    found in the “experimental tube” traversed by the luminous beam.

    For a long time I was troubled by the appearance there of floating
    dust, which, though invisible in diffuse daylight, was at once
    revealed by a powerfully condensed beam. Two tubes were placed in
    succession in the path of the dust: the one containing fragments of
    glass wetted with concentrated sulphuric acid; the other, fragments
    of marble wetted with a strong solution of caustic potash. To my
    astonishment it passed through both. The air of the Royal
    Institution, sent through these tubes at a rate sufficiently slow to
    dry it and to remove its carbonic acid, carried into the
    experimental tube a considerable amount of mechanically-suspended
    matter, which was illuminated when the beam passed through the tube.
    The effect was substantially the same when the air was permitted to
    bubble through the liquid acid and through the solution of potash.

    Thus, on the 5th of October, 1868, successive charges of air were
    admitted through the potash and sulphuric acid into the exhausted
    experimental tube. Prior to the admission of the air the tube was
    _optically empty_; it contained nothing competent to scatter the
    light. After the air had entered the tube, the conical track of the
    electric beam was in all cases clearly revealed. This, indeed, was a
    daily observation at the time to which I now refer.

    I tried to intercept this floating matter in various ways; and on
    the day just mentioned, prior to sending the air through the drying
    apparatus, I carefully permitted it to pass over the tip of a
    spirit-lamp flame. The floating matter no longer appeared, having
    been burnt up by the flame. It was, therefore, _organic matter_.
    When the air was sent too rapidly through the flame, a fine blue
    cloud was found in the experimental tube. This was the _smoke_ of
    the organic particles. I was by no means prepared for this result;
    for I had thought, with the rest of the world, that the dust of our
    air was, in great part, inorganic and non-combustible.

    Mr. Valentin had the kindness to procure for me a small gas-furnace,
    containing a platinum tube, which could be heated to vivid redness.
    The tube also contained a roll of platinum gauze, which, while it
    permitted the air to pass through it, insured the practical contact
    of the dust with the incandescent metal. The air of the laboratory
    was permitted to enter the experimental tube, sometimes through the
    cold, and sometimes through the heated tube of platinum. The
    rapidity of admission was also varied. In the first column of the
    following table the quantity of air operated on is expressed by the
    number of inches which the mercury gauge of the air-pump sank when
    the air entered. In the second column the condition of the platinum
    tube is mentioned, and in the third the state of the air which
    entered the experimental tube.

                        State of        State of
             Quantity   Platinum        Experimental
             of Air.    Tube.           Tube.

             15 inches  Cold            Full of particles.

             15 inches  Red-hot         Optically empty.

             15 inches  Cold            Full of particles.

             15 inches  Red-hot         Optically empty.

             15 inches  Cold            Full of particles.

             15 inches  Red-hot         Optically empty.


    The phrase “optically empty” shows that when the conditions of
    perfect combustion were present, the floating matter totally
    disappeared. It was wholly burnt up, leaving not a trace of residue.
    From spectrum analysis, however, we know that soda floats in the
    air; these organic dust particles are, I believe, the _rafts_ that
    support it, and when they are removed it sinks and vanishes.

    When the passage of the air was so rapid as to render imperfect the
    combustion of the floating matter, instead of optical emptiness a
    fine blue cloud made its appearance in the experimental tube. The
    following series of results illustrate this point:


        Quantity.         Platinum Tube.    Experimental Tube.
        15 inches, slow   Cold              Full of particles.
        15 inches, slow   Red-hot           Optically empty.
        15 inches, quick  Red-hot           A blue cloud.
        15 inches, quick  Intensely hot     A fine blue cloud.


    The optical character of these clouds was totally different from
    that of the dust which produced them. At right angles to the
    illuminating beam they discharged perfectly polarized light The
    cloud could be utterly quenched by a transparent Nicol’s prism, and
    the tube containing it reduced to optical emptiness.

    The particles floating in the air of London being thus proved to be
    organic, I sought to burn them up at the focus of a concave
    reflector. One of the powerfully convergent mirrors employed in my
    experiments on combustion by dark rays was here made use of, but I
    failed in the attempt. Doubtless the floating particles are in part
    transparent to radiant heat, and are so far incombustible by such
    heat. Their rapid motion through the focus also aids their escape.
    They do not linger there sufficiently long to be consumed. A flame
    it was evident would burn them up, but I thought the presence of the
    flame would mask its own action among the particles.

    In a cylindrical beam, which powerfully illuminated the dust of the
    laboratory, was placed an ignited spirit-lamp. Mingling with the
    flame, and round its rim, were seen wreaths of darkness resembling
    an intensely black smoke. On lowering the flame below the beam the
    same dark masses stormed upwards. They were at times blacker than
    the blackest smoke that I have ever seen issuing from the funnel of
    a steamer, and their resemblance to smoke was so perfect as to lead
    the most practiced observer to conclude that the apparently pure
    flame of the alcohol lamp required but a beam of sufficient
    intensity to reveal its clouds of liberated carbon.

    But is the blackness smoke? The question presented itself in a
    moment. A red-hot poker was placed underneath the beam, and from it
    the black wreaths also ascended. A large hydrogen flame was next
    employed, and it produced those whirling masses of darkness far more
    copiously than either the spirit-flame or poker. Smoke was,
    therefore, out of the question.

    What, then, was the blackness? It was simply that of stellar space;
    that is to say, blackness resulting from the absence from the track
    of the beam of all matter competent to scatter its light. When the
    flame was placed below the beam the floating matter was destroyed
    _in situ_; and the air, freed from this matter, rose into the beam,
    jostled aside the illuminated particles and substituted for their
    light the darkness due to its own perfect transparency. Nothing
    could more forcibly illustrate the invisibility of the agent which
    renders all things visible. The beam crossed, unseen, the black
    chasm formed by the transparent air, while at both sides of the gap
    the thick-strewn particles shone out like a luminous solid under the
    powerful illumination.

    But here a difficulty meets us. It is not necessary to burn the
    particles to produce a stream of darkness. Without actual
    combustion, currents may be generated which shall exclude the
    floating matter, and therefore appear dark amid the surrounding
    brightness. I noticed this effect first on placing a red-hot copper
    ball below the beam, and permitting it to remain there until its
    temperature had fallen below that of boiling water. The dark
    currents, though much enfeebled, were still produced. They may also
    be produced by a flask filled with hot water.

    To study this effect a platinum wire was stretched across the beam,
    the two ends of the wire being connected with the two poles of a
    voltaic battery. To regulate the strength of the current a rheostat
    was placed in the circuit. Beginning with a feeble current the
    temperature of the wire was gradually augmented, but before it
    reached the heat of ignition, a flat stream of air rose from it,
    which when looked at edgeways appeared darker and sharper than one
    of the blackest lines of Fraunhofer in the solar spectrum. Right and
    left of this dark vertical band the floating matter rose upwards,
    bounding definitely the non-luminous stream of air. What is the
    explanation? Simply this. The hot wire rarefied the air in contact
    with it, but it did not equally lighten the floating matter. The
    convection current of pure air therefore passed upwards _among the
    particles_, dragging them after it right and left, but forming
    between them an impassable black partition. In this way we render an
    account of the dark currents produced by bodies at a temperature
    below that of combustion.

    Oxygen, hydrogen, nitrogen, carbonic acid, so prepared as to exclude
    all floating particles, produce the darkness when poured or blown
    into the beam. Coal-gas does the same. An ordinary glass shade
    placed in the air with its mouth downwards permits the track of the
    beam to be seen crossing it. Let coal-gas or hydrogen enter the
    shade by a tube reaching to its top, the gas gradually fills the
    shade from the top downwards. As soon as it occupies the space
    crossed by the beam, the luminous track is instantly abolished.
    Lifting the shade so as to bring the common boundary of gas and air
    above the beam, the track flashes forth. After the shade is full, if
    it be inverted, the gas passes upwards like a black smoke among the
    illuminated particles.

    The air of our London rooms is loaded with this organic dust, nor is
    the country air free from its pollution. However ordinary daylight
    may permit it to disguise itself, a sufficiently powerful beam
    causes the air in which the dust is suspended to appear as a
    semi-solid rather than as a gas. Nobody could, in the first
    instance, without repugnance place the mouth at the illuminated
    focus of the electric beam and inhale the dirt revealed there. Nor
    is the disgust abolished by the reflection that, although we do not
    see the nastiness, we are churning it in our lungs every hour and
    minute of our lives. There is no respite to this contact with dirt;
    and the wonder is, not that we should from time to time suffer from
    its presence, but that so small a portion of it would appear to be
    deadly to man.

    And what is this portion? It was some time ago the current belief
    that epidemic diseases generally were propagated by a kind of
    malaria, which consisted of organic matter in a state of
    _motor-decay_; that when such matter was taken into the body through
    the lungs or skin, it had the power of spreading there the
    destroying process which had attacked itself. Such a spreading power
    was visibly exerted in the case of yeast. A little leaven was seen
    to leaven the whole lump, a mere speck of matter in this supposed
    state of decomposition being apparently competent to propagate
    indefinitely its own decay. Why should not a bit of rotten malaria
    work in a similar manner within the human frame? In 1836 a very
    wonderful reply was given to this question. In that year Cagniard de
    la Tour discovered the _yeast plant_, a living organism, which, when
    placed in a proper medium, feeds, grows, and reproduces itself, and
    in this way carries on the process which we name fermentation.
    Fermentation was thus proved to be a product of life instead of a
    process of decay.

    Schwann, of Berlin, discovered the yeast plant independently, and in
    February, 1837, he also announced the important result, that when a
    decoction of meat is effectually screened from ordinary air, and
    supplied solely with air which has been raised to a high
    temperature, putrefaction never sets in. Putrefaction, therefore, he
    affirmed to be caused by something derived from the air, which
    something could be destroyed by a sufficiently high temperature. The
    experiments of Schwann were repeated and confirmed by Helmholtz and
    Ure. But as regards fermentation, the minds of chemists, influenced
    probably by the great authority of Gay-Lussac, who ascribed
    putrefaction to the action of oxygen, fell back upon the old notion
    of matter in a state of decay. It was not the living yeast plant,
    but the dead or dying parts of it, which, assailed by oxygen,
    produced the fermentation. This notion was finally exploded by
    Pasteur. He proved that the so-called “ferments” are not such; that
    the true ferments are organized beings which find in the reputed
    ferments their necessary food.

    Side by side with these researches and discoveries, and fortified by
    them and others, has run the _germ theory_ of epidemic disease. The
    notion was expressed by Kircher, and favored by Linnæus, that
    epidemic diseases are due to germs which float in the atmosphere,
    enter the body, and produce disturbance by the development within
    the body of parasitic life. While it was still struggling against
    great odds, this theory found an expounder and a defender in the
    President of this Institution. At a time when most of his medical
    brethren considered it a wild dream, Sir Henry Holland contended
    that some form of the germ theory was probably true. The strength of
    this theory consists in the perfect parallelism of the phenomena of
    contagious disease with those of life. As a planted acorn gives
    birth to an oak competent to produce a whole crop of acorns, each
    gifted with the power of reproducing its parent tree, and as thus
    from a single seedling a whole forest may spring, so these epidemic
    diseases literally plant their seeds, grow, and shake abroad new
    germs, which, meeting in the human body their proper food and
    temperature, finally take possession of whole populations. Thus
    Asiatic cholera, beginning in a small way in the Delta of the
    Ganges, contrived in seventeen years to spread itself over nearly
    the whole habitable world. The development from an infinitesimal
    speck of the virus of small-pox of a crop of pustules, each charged
    with the original poison, is another illustration. The reappearance
    of the scourge, as in the case of the _Dreadnought_ at Greenwich,
    reported on so ably by Dr. Budd and Mr. Busk, receives a
    satisfactory explanation from the theory which ascribes it to the
    lingering of germs about the infected place.

    Surgeons have long known the danger of permitting air to enter an
    open abscess. To prevent its entrance they employ a tube called a
    cannula, to which is attached a sharp steel point called a trocar.
    They puncture with the steel point, and by gentle pressure they
    force the pus through the cannula. It is necessary to be very
    careful in cleansing the instrument; and it is difficult to see how
    it can be cleansed by ordinary methods in air loaded with organic
    impurities, as we have proved our air to be. The instrument ought,
    in fact, to be made as hot as its temper will bear. But this is not
    done, and hence, notwithstanding all the surgeon’s care,
    inflammation often sets in after the first operation, rendering
    necessary a second and a third. Rapid putrefaction is found to
    accompany this new inflammation. The pus, moreover, which was sweet
    at first, and showed no trace of animal life, is now fetid, and
    swarming with active little organisms called vibrios. Prof. Lister,
    from whose recent lecture this fact is derived, contends, with every
    show of reason, that this rapid putrefaction and this astounding
    development of animal life are due to the entry of germs into the
    abscess during the first operation, and their subsequent nurture and
    development under favorable conditions of food and temperature. The
    celebrated physiologist and physicist, Helmholtz, is attacked
    annually by hay-fever. From the 20th of May to the end of June he
    suffers from a catarrh of the upper air-passages; and he has found
    during this period, and at no other, that his nasal secretions are
    peopled by these vibrios. They appear to nestle by preference in the
    cavities and recesses of the nose, for a strong sneeze is necessary
    to dislodge them.

    These statements sound uncomfortable; but by disclosing our enemy
    they enable us to fight him. When he clearly eyes his quarry the
    eagle’s strength is doubled, and his swoop is rendered sure. If the
    germ theory be proved true, it will give a definiteness to our
    efforts to stamp out disease which they could not previously
    possess. And it is only by definite effort under its guidance that
    its truth or falsehood can be established. It is difficult for an
    outsider like myself to read without sympathetic emotion such papers
    as those of Dr. Budd, of Bristol, on cholera, scarlet-fever, and
    small-pox. He is a man of strong imagination, and may occasionally
    take a flight beyond his facts; but without this dynamic heat of
    heart, the stolid inertia of the free-born Briton cannot be
    overcome. And as long as the heat is employed to warm up the truth
    without singeing it overmuch; as long as this enthusiasm can
    overmatch its mistakes by unequivocal examples of success, so long
    am I disposed to give it a fair field to work in, and to wish it God
    speed.

    But let us return to our dust. It is needless to remark that it
    cannot be blown away by an ordinary bellows; or, more correctly, the
    place of the particles blown away is in this case supplied by others
    ejected from the bellows, so that the track of the beam remains
    unimpaired. But if the nozzle of a good bellows be filled with
    cotton wool not too tightly packed, the air urged through the wool
    is filtered of its floating matter, and it then forms a clean band
    of darkness in the illuminated dust. This was the filter used by
    Schroëder in his experiments on spontaneous generation, and turned
    subsequently to account in the excellent researches of Pasteur.
    Since 1868 I have constantly employed it myself.

    But by far the most interesting and important illustration of this
    filtering process is furnished by the human breath. I fill my lungs
    with ordinary air and breathe through a glass tube across the
    electric beam. The condensation of the aqueous vapor of the breath
    is shown by the formation of a luminous white cloud of delicate
    texture. It is necessary to abolish this cloud, and this may be done
    by drying the breath previous to its entering into the beam; or
    still more simply, by warming the glass tube. When this is done the
    luminous track of the beam is for a time uninterrupted. The breath
    impresses upon the floating matter a transverse motion, but the dust
    from the lungs makes good the particles displaced. But after some
    time an obscure disc appears upon the beam, the darkness of which
    increases, until finally, towards the end of the expiration, the
    beam is, as it were, pierced by an intensely black hole, in which no
    particles whatever can be discerned. The air, in fact, has so lodged
    its dirt within the lungs as to render the last portions of the
    expired breath absolutely free from suspended matter. This
    experiment may be repeated any number of times with the same result.
    It renders the distribution of the dirt within the lungs as manifest
    as if the chest were transparent.

    I now empty my lungs as perfectly as possible, and placing a handful
    of cotton wool against my mouth and nostrils, inhale through it.
    There is no difficulty in thus filling the lungs with air. On
    expiring this air through the glass tube, its freedom from floating
    matter is at once manifest. From the very beginning of the act of
    expiration the beam is pierced by a black aperture. The first puff
    from the lungs abolishes the illuminated dust and puts a patch of
    darkness in its place, and the darkness continues throughout the
    entire course of the expiration. When the tube is placed below the
    beam and moved to and fro, the same smoke-like appearance as that
    obtained with a flame is observed. In short, the cotton wool, when
    used in sufficient quantity, completely intercepts the floating
    matter on its way to the lungs.

    And here we have revealed to us the true philosophy of a practice
    followed by medical men, more from instinct than from actual
    knowledge. In a contagious atmosphere the physician places a
    handkerchief to his mouth and inhales through it. In doing so he
    unconsciously holds back the dirt and germs of the air. If the
    poison were a gas it would not be thus intercepted. On showing this
    experiment with the cotton wool to Dr. Bence Jones, he immediately
    repeated it with a silk handkerchief. The result was substantially
    the same, though, as might be expected, the wool is by far the
    surest filter. The application of these experiments is obvious. If a
    physician wishes to hold back from the lungs of his patient, or from
    his own, the germs by which contagious disease is said to be
    propagated, he will employ a cotton wool respirator. After the
    revelations of this evening, such respirators must, I think, come
    into general use as a defence against contagion. In the crowded
    dwellings of the London poor, where the isolation of the sick is
    difficult, if not impossible, the noxious air around the patient
    may, by this simple means, be restored to practical purity. Thus
    filtered, attendants may breathe the air unharmed. In all
    probability the protection of the lungs will be protection of the
    entire system. For it is exceedingly probable that the germs which
    lodge in the air-passages, and which, at their leisure, can work
    their way across the mucous membrane, are those which sow in the
    body epidemic disease. If this be so, then disease can certainly be
    warded off by filters of cotton wool. I should be most willing to
    test their efficacy in my own person. And time will decide whether
    in lung diseases also the woolen respirator cannot abate irritation,
    if not arrest decay. By its means, so far as the germs are
    concerned, the air of the highest Alps may be brought into the
    chamber of the invalid.

                                  III.

                   Scientific Use of the Imagination.

    I carried with me to the Alps this year the heavy burden of this
    evening’s work. In the way of new investigation I had nothing
    complete enough to be brought before you; so all that remained to me
    was to fall back upon such residues as I could find in the depths of
    consciousness, and out of them to spin the fiber and weave the web
    of this discourse. Save from memory I had no direct aid upon the
    mountains; but to spur up the emotions, on which so much depends, as
    well as to nourish indirectly the intellect and will, I took with me
    two volumes of poetry, Goethe’s “Farbenlehre,” and the work on
    “Logic” recently published by Mr. Alexander Bain. The spur, I am
    sorry to say, was no match for the integument of dullness it had to
    pierce.

    In Goethe, so glorious otherwise, I chiefly noticed the
    self-inflicted hurts of genius, as it broke itself in vain against
    the philosophy of Newton. For a time Mr. Bain became my principal
    companion. I found him learned and practical, shining generally with
    a dry light, but exhibiting at times a flush of emotional strength,
    which proved that even logicians share the common fire of humanity.
    He interested me most when he became the mirror of my own condition.
    Neither intellectually nor socially is it good for man to be alone,
    and the griefs of thought are more patiently borne when we find that
    they have been experienced by another. From certain passages in his
    book I could infer that Mr. Bain was no stranger to such sorrows.
    Take this passage as an illustration. Speaking of the ebb of
    intellectual force which we all from time to time experience, Mr.
    Bain says: “The uncertainty where to look for the next opening of
    discovery brings the pain of conflict and the debility of
    indecision.” These words have in them the true ring of personal
    experience.

    The action of the investigator is periodic. He grapples with a
    subject of inquiry, wrestles with it, overcomes it, exhausts, it may
    be, both himself and it for the time being. He breathes a space, and
    then renews the struggle in another field. Now this period of
    halting between two investigations is not always one of pure repose.
    It is often a period of doubt and discomfort, of gloom and ennui.
    “The uncertainty where to look for the next opening of discovery
    brings the pain of conflict and the debility of indecision.” Such
    was my precise condition in the Alps this year; in a score of words
    Mr. Bain has here sketched my mental diagnosis; and it was under
    these evil circumstances that I had to equip myself for the hour and
    the ordeal that are now come.

    Gladly, however, as I should have seen this duty in other hands, I
    could by no means shrink from it. Disloyalty would have been worse
    than failure. In some fashion or other—feebly or strongly, meanly or
    manfully, on the higher levels of thought, or on the flats of
    commonplace—the task had to be accomplished. I looked in various
    directions for help and furtherance; but without me for a time I saw
    only “antres vast,” and within me “deserts idle.” My case resembled
    that of a sick doctor who had forgotten his art, and sorely needed
    the prescription of a friend. Mr. Bain wrote one for me. He said:
    “Your present knowledge must forge the links of connection between
    what has been already achieved and what is now required.”

    In these words he admonished me to review the past and recover from
    it the broken ends of former investigations. I tried to do so.
    Previous to going to Switzerland I had been thinking much of light
    and heat, of magnetism and electricity, of organic germs, atoms,
    molecules, spontaneous generation, comets and skies. With one or
    another of these I now sought to re-form an alliance, and finally
    succeeded in establishing a kind of cohesion between thought and
    light. The wish grew within me to trace, and to enable you to trace,
    some of the more occult operations of this agent. I wished, if
    possible, to take you behind the drop-scene of the senses, and to
    show you the hidden mechanism of optical action. For I take it to be
    well worth the while of the scientific teacher to take some pains,
    and even great pains, to make those whom he addresses co-partners of
    his thoughts. To clear his own mind in the first place from all haze
    and vagueness, and then to project into language which shall leave
    no mistake as to his meaning—which shall leave even his errors
    naked—the definite ideas he has shaped.

    A great deal is, I think, possible to scientific exposition
    conducted in this way. It is possible, I believe, even before an
    audience like the present, to uncover to some extent the unseen
    things of nature, and thus to give, not only to professed students,
    but to others with the necessary bias, industry and capacity, an
    intelligent interest in the operations of science. Time and labor
    are necessary to this result, but science is the gainer from the
    public sympathy thus created.

    How then are those hidden things to be revealed? How, for example,
    are we to lay hold of the physical basis of light, since, like that
    of life itself, it lies entirely without the domain of the senses?
    Now, philosophers may be right in affirming that we cannot transcend
    experience. But we can, at all events, carry it a long way from its
    origin. We can also magnify, diminish, qualify, and combine
    experiences, so as to render them fit for purposes entirely new. We
    are gifted with the power of imagination, combining what the Germans
    called _Anschauungsgabe_ and _Einbildungskraft_, and by this power
    we can lighten the darkness which surrounds the world of the senses.

    There are tories even in science who regard imagination as a faculty
    to be feared and avoided rather than employed. They had observed its
    action in weak vessels and were unduly impressed by its disasters.
    But they might with equal justice point to exploded boilers as an
    argument against the use of steam. Bounded and conditioned by
    coöperant reason, imagination becomes the mightiest instrument of
    the physical discoverer. Newton’s passage from a falling apple to a
    falling moon was a leap of the imagination. When William Thomson
    tries to place the ultimate particles of matter between his compass
    points, and to apply to them a scale of millimeters, it is an
    exercise of the imagination. And in much that has been recently said
    about protoplasm and life, we have the outgoings of the imagination
    guided and controlled by the known analogies of science. In fact,
    without this power our knowledge of nature would be a mere
    tabulation of coëxistences and sequences. We should still believe in
    the succession of day and night, of summer and winter; but the soul
    of force would be dislodged from our universe; casual relations
    would disappear, and with them that science which is now binding the
    parts of nature to an organic whole.

    I should like to illustrate by a few simple instances the use that
    scientific men have already made of this power of imagination, and
    to indicate afterwards some of the further uses that they are likely
    to make of it. Let us begin with the rudimentary experiences.
    Observe the falling of heavy rain drops into a tranquil pond. Each
    drop as it strikes the water becomes a center of disturbance, from
    which a series of ring ripples expands outwards. Gravity and inertia
    are the agents by which this wave motion is produced, and a rough
    experiment will suffice to show that the rate of propagation does
    not amount to a foot a second.

    A series of slight mechanical shocks is experienced by a body
    plunged in the water as the wavelets reach it in succession. But a
    finer motion is at the same time set up and propagated. If the head
    and ears be immersed in the water, as in an experiment of
    Franklin’s, the shock of the drop is communicated to the auditory
    nerve—the _tick_ of the drop is heard. Now this sonorous impulse is
    propagated, not at the rate of a foot a second, but at the rate of
    4,700 feet a second. In this case it is not the gravity but the
    _elasticity_ of the water that is the urging force. Every liquid
    particle pushed against its neighbor delivers up its motion with
    extreme rapidity, and the pulse is propagated as a thrill. The
    incompressibility of water, as illustrated by the famous Florentine
    experiment, is a measure of its elasticity, and to the possession of
    this property in so high a degree the rapid transmission of a
    sound-pulse through water is to be ascribed.

    But water, as you know, is not necessary to the conduction of sound;
    air is its most common vehicle. And you know that when the air
    possesses the particular density and elasticity corresponding to the
    temperature of freezing water, the velocity of sound in it is 1,090
    feet a second. It is almost exactly one-fourth of the velocity in
    water; the reason being that though the greater weight of the water
    tends to diminish the velocity, the enormous molecular elasticity of
    the liquid far more than atones for the disadvantage due to weight.
    By various contrivances we can compel the vibrations of the air to
    declare themselves; we know the length and frequency of sonorous
    waves, and we have also obtained great mastery over the various
    methods by which the air is thrown into vibration. We know the
    phenomena and laws of vibrating rods, of organ pipes, strings,
    membranes, plates, and bells. We can abolish one sound by another.
    We know the physical meaning of music and noise, of harmony and
    discord. In short, as regards sound we have a very clear notion of
    the external physical processes which correspond to our sensations.

    In these phenomena of sound we travel a very little way from
    downright sensible experience. Still the imagination is to some
    extent exercised. The bodily eye, for example, cannot see the
    condensations and rarefactions of the waves of sound. We construct
    them in thought, and we believe as firmly in their existence as in
    that of the air itself. But now our experience has to be carried
    into a new region, where a new use is to be made of it.

    Having mastered the cause and mechanism of sound, we desire to know
    the cause and mechanism of light. We wish to extend our inquiries
    from the auditory nerve to the optic nerve. Now there is in the
    human intellect a power of expansion—I might almost call it a power
    of creation—which is brought into play by the simple brooding upon
    facts. The legend of the Spirit brooding over chaos may have
    originated in a knowledge of this power. In the case now before us
    it has manifested itself by transplanting into space, for the
    purposes of light, an adequately modified form of the mechanism of
    sound. We know intimately whereon the velocity of sound depends.
    When we lessen the density of a medium and preserve its elasticity
    constant, we augment the velocity. When we highten the elasticity
    and keep the density constant, we also augment the velocity. A small
    density, therefore, and a great elasticity are the two things
    necessary to rapid propagation.

    Now light is known to move with the astounding velocity of 185,000
    miles a second. How is such a velocity to be obtained? By boldly
    diffusing in space a medium of the requisite tenuity and elasticity.
    Let us make such a medium our starting point, endowing it with one
    or two other necessary qualities; let us handle it in accordance
    with strict mechanical laws; give to every step of your deduction
    the surety of the syllogism; carry it thus forth from the world of
    imagination to the world of sense, and see whether the final outcrop
    of the deduction be not the very phenomena of light which ordinary
    knowledge and skilled experiment reveal. If in all the multiplied
    varieties of these phenomena, including those of the most remote and
    entangled description, this fundamental conception always brings us
    face to face with the truth; if no contradiction to our deductions
    from it be found in external nature; if, moreover, it has actually
    forced upon our attention phenomena which no eye had previously
    seen, and which no mind had previously imagined; if by it we are
    gifted with a power of prescience which has never failed when
    brought to an experimental test; such a conception, which never
    disappoints us, but always lands us on the solid shores of fact,
    must, we think, be something more than a mere figment of the
    scientific fancy. In forming it that composite and creative unity in
    which reason and imagination are together blent, has, we believe,
    led us into a world not less real than that of the senses, and of
    which the world of sense itself is the suggestion and justification.

    Far be it from me, however, to wish to fix you immovably in this or
    in any other theoretic conception. With all our belief of it, it
    will be well to keep the theory plastic and capable of change. You
    may, moreover, urge that although the phenomena occur _as if_ the
    medium existed, the absolute demonstration of its existence is still
    wanting. Far be it from me to deny to this reasoning such validity
    as it may fairly claim. Let us endeavor by means of analogy to form
    a fair estimate of its force.

    You believe that in society you are surrounded by reasonable beings
    like yourself. You are, perhaps, as firmly convinced of this as of
    anything. What is your warrant for this conviction? Simply and
    solely this, your fellow-creatures behave as if they were
    reasonable; the hypothesis, for it is nothing more, accounts for the
    facts. To take an eminent example, you believe that our president is
    a reasonable being. Why? There is no known method of superposition
    by which any one of us can apply himself intellectually to another
    so as to demonstrate coincidence as regards the possession of
    reason. If, therefore, you hold our president to be reasonable, it
    is because he behaves _as if_ he were reasonable. As in the case of
    the ether, beyond the “_as if_” you cannot go. Nay, I should not
    wonder if a close comparison of the data on which both inferences
    rest caused many respectable persons to conclude that the ether had
    the best of it.

    This universal medium, this light-ether as it is called, is a
    vehicle, not an origin of wave motion. It receives and transmits,
    but it does not create. Whence does it derive the motions it
    conveys? For the most part from luminous bodies. By this motion of a
    luminous body I do not mean its sensible motion, such as the flicker
    of a candle, or the shooting out of red prominences from the limb of
    the sun. I mean an intestine motion of the atoms or molecules of the
    luminous body. But here a certain reserve is necessary. Many
    chemists of the present day refuse to speak of atoms and molecules
    as real things. Their caution leads them to stop short of the clear,
    sharp, mechanically intelligible atomic theory enunciated by Dalton,
    or any form of that theory, and to make the doctrine of multiple
    proportions their intellectual bourne. I respect the caution, though
    I think it is here misplaced. The chemists who recoil from these
    notions of atoms and molecules accept without hesitation the
    undulatory theory of light. Like you and me they one and all believe
    in an ether and its light-producing waves. Let us consider what this
    belief involves.

    Bring your imaginations once more into play and figure a series of
    sound waves passing through air. Follow them up to their origin, and
    what do you there find? A definite, tangible, vibrating body. It may
    be the vocal chords of a human being, it may be an organ pipe, or it
    may be a stretched string. Follow in the same manner a train of
    ether waves to their source, remembering at the same time that your
    ether is matter, dense, elastic, and capable of motions subject to
    and determined by mechanical laws. What then do you expect to find
    as the source of a series of ether waves? Ask your imagination if it
    will accept a vibrating multiple proportion—a numerical ratio in a
    state of oscillation? I do not think it will. You cannot crown the
    edifice by this abstraction. The scientific imagination, which is
    here authoritative, demands as the origin and cause of a series of
    ether waves a particle of vibrating matter quite as definite, though
    it may be excessively minute, as that which gives origin to a
    musical sound. Such a particle we name an atom or a molecule. I
    think the imagination when focused so as to give definition without
    penumbral haze is sure to realize this image at last.

    To preserve thought continuous throughout this discourse, to prevent
    either lack of knowledge or failure of memory from producing any
    rent in our picture, I here propose to run rapidly over a bit of
    ground which is probably familiar to most of you, but which I am
    anxious to make familiar to you all.

    The waves generated in the ether by the swinging atoms of luminous
    bodies are of different lengths and amplitudes. The amplitude is the
    width of swing of the individual particles of the wave. In water
    waves it is the hight of the crest above the trough, while the
    length of the wave is the distance between two consecutive crests.
    The aggregate of waves emitted by the sun may be broadly divided
    into two classes, the one class competent, the other incompetent, to
    excite vision.

    But the light-producing waves differ markedly among themselves in
    size, form, and force. The length of the largest of these waves is
    about twice that of the smallest, but the amplitude of the largest
    is probably a hundred times that of the smallest. Now the force or
    energy of the wave, which, expressed with reference to sensation,
    means the intensity of the light, is proportional to the square of
    the amplitude. Hence the amplitude being one hundred-fold, the
    energy of the largest light-giving waves would be ten thousand-fold
    that of the smallest. This is not improbable. I use these figures,
    not with a view to numerical accuracy, but to give you definite
    ideas of the differences that probably exist among the light-giving
    waves. And if we take the whole range of solar radiation into
    account—its non-visual as well as its visual waves—I think it
    probable that the force or energy of the largest wave is a million
    times that of the smallest.

    Turned into their equivalents of sensation, the different light
    waves produce different colors. Red, for example, is produced by the
    largest waves, violet by the smallest, while green is produced by a
    wave of intermediate length and amplitude. On entering from air into
    more highly refracting substances, such as glass or water or the
    sulphide of carbon, all the waves are retarded, but the smallest
    ones most. This furnishes a means of separating the different
    classes of waves from each other—in other words, of analyzing the
    light. Sent through a refracting prism, the waves of the sun are
    turned aside in different degrees from their direct course, the red
    least, the violet most. They are virtually pulled asunder, and they
    paint upon a white screen placed to receive them “the solar
    spectrum.”

    Strictly speaking, the spectrum embraces an infinity of colors, but
    the limits of language and of our powers of distinction cause it to
    be divided into seven segments: Red, orange, yellow, green, blue,
    indigo, violet. These are the seven primary or prismatic colors.
    Separately, or mixed in various proportions, the solar waves yield
    all the colors observed in nature and employed in art. Collectively
    they give us the impression of whiteness. Pure unsifted solar light
    is white; and if all the wave constituents of such light be reduced
    in the same proportion, the light, though diminished in intensity,
    will still be white. The whiteness of Alpine snow with the sun
    shining upon it is barely tolerable to the eye. The same snow under
    an overcast firmament is still white. Such a firmament enfeebles the
    light by reflection, and when we lift ourselves above a
    cloud-field—to an Alpine summit, for instance, or to the top of
    Snowdon—and see, in the proper direction, the sun shining on the
    clouds, they appear dazzlingly white. Ordinary clouds, in fact,
    divide the solar light impinging on them into two parts—a reflected
    part and a transmitted part, in each of which the proportions of
    wave motion which produce the impression of whiteness are sensibly
    preserved.

    It will be understood that the conditions of whiteness would fail if
    all the waves were diminished _equally_, or by the same absolute
    quantity. They must be reduced _proportionately_ instead of equally.
    If by the act of reflection the waves of red light are split into
    exact halves, then, to preserve the light white, the waves of
    yellow, orange, green, and blue must also be split into exact
    halves. In short, the reduction must take place, not by absolutely
    equal quantities, but by equal fractional parts. In white light the
    preponderance as regards energy of the larger over the smaller waves
    must always be immense. Were the case otherwise, the physiological
    correlative, _blue_, of the smaller waves would have the upper hand
    in our sensations.

    My wish to render our mental images complete, causes me to dwell
    briefly upon these known points, and the same wish will cause me to
    linger a little longer among others. But here I am disturbed by my
    reflections. When I consider the effect of dinner upon the nervous
    system, and the relation of that system to the intellectual powers I
    am now invoking; when I remember that the universal experience of
    mankind has fixed upon certain definite elements of perfection in an
    after-dinner speech, and when I think how conspicuous by their
    absence these elements are on the present occasion, the thought is
    not comforting to a man who wishes to stand well with his
    fellow-creatures in general, and with the members of the British
    Association in particular. My condition might well resemble that of
    the ether, which is scientifically defined as an assemblage of
    vibrations. And the worst of it is that, unless you reverse the
    general verdict regarding the effect of dinner, and prove in your
    own persons that a uniform experience need not continue
    uniform—which will be a great point gained for some people—these
    tremors of mine are likely to become more and more painful. But I
    call to mind the comforting words of an inspired, though uncanonical
    writer, who admonishes us in the Apocrypha that fear is a bad
    counsellor. Let me then cast him out, and let me trustfully assume
    that you will one and all postpone that balmy sleep, of which dinner
    might, under the circumstances, be regarded as the indissoluble
    antecedent, and that you will manfully and womanfully prolong your
    investigations of the ether and its waves into regions which have
    been hitherto crossed by the pioneers of science alone.

    Not only are the waves of ether reflected by clouds, by solids, and
    by liquids, but when they pass from light air to dense, or from
    dense air to light, a portion of the wave motion is always
    reflected. Now our atmosphere changes continually in density from
    top to bottom. It will help our conceptions if we regard it as made
    up of a series of thin concentric layers or shells of air, each
    shell being of the same density throughout, and a small and sudden
    change of density occurring in passing from shell to shell. Light
    would be reflected at the limiting surfaces of all these shells, and
    their action would be practically the same as that of the real
    atmosphere.

    And now I would ask your imagination to picture this act of
    reflection. What must become of the reflected light? The atmospheric
    layers turn their convex surfaces towards the sun; they are so many
    convex mirrors of feeble power, and you will immediately perceive
    that the light regularly reflected from these surfaces cannot reach
    the earth at all, but is dispersed in space.

    But though the sun’s light is not reflected in this fashion from the
    ærial layers to the earth, there is indubitable evidence to show
    that the light of our firmament is reflected light. Proofs of the
    most cogent description could be here adduced; but we need only
    consider that we receive light at the same time from all parts of
    the hemisphere of heaven. The light of the firmament comes to us
    across the direction of the solar rays, and even against the
    direction of the solar rays; and this lateral and opposing rush of
    wave motion can only be due to the rebound of the waves from the air
    itself, or from something suspended in the air. It is also evident
    that, unlike the action of clouds, the solar light is not reflected
    by the sky in the proportions which produce white. The sky is blue,
    which indicates a deficiency on the part of the larger waves. In
    accounting for the color of the sky, the first question suggested by
    analogy would undoubtedly be, is not the air blue? The blueness of
    the air has, in fact, been given as a solution of the blueness of
    the sky. But reason basing itself on observation asks in reply, How,
    if the air be blue, can the light of sunrise and sunset, which
    travels through vast distances of air, be yellow, orange, or even
    red? The passage of the white solar light through a blue medium
    could by no possibility redden the light. The hypothesis of a blue
    air is therefore untenable. In fact, the agent, whatever it is,
    which sends us the light of the sky, exercises in so doing a
    dichroitic action. The light reflected is blue, the light
    transmitted is orange or red. A marked distinction is thus exhibited
    between the matter of the sky and that of an ordinary cloud, which
    latter exercises no such dichroitic action.

    By the force of imagination and reason combined we may penetrate
    this mystery also. The cloud takes no note of size on the part of
    the waves of ether, but reflects them all alike. It exercises no
    selective action. Now the cause of this may be that the cloud
    particles are so large in comparison with the size of the waves of
    ether as to reflect them all indifferently. A broad cliff reflects
    an Atlantic roller as easily as a ripple produced by a sea bird’s
    wing; and in the presence of large reflecting surfaces the existing
    differences of magnitude among the waves of ether may disappear. But
    supposing the reflecting particles, instead of being very large, to
    be very small, in comparison with the size of the waves. In this
    case, instead of the whole wave being fronted and in great part
    thrown back, a small portion only is shivered off. The great mass of
    the wave passes over such a particle without reflection. Scatter
    then, a handful of such minute foreign particles in our atmosphere,
    and set imagination to watch their action upon the solar waves.
    Waves of all sizes impinge upon the particles, and you see at every
    collision a portion of the impinging wave struck off by reflection.
    All the waves of the spectrum, from the extreme red to the extreme
    violet, are thus acted upon. But in what proportions will the waves
    be scattered? A clear picture will enable us to anticipate the
    experimental answer. Remembering that the red waves are to the blue
    much in the relation of billows to ripples, let us consider whether
    those extremely small particles are competent to scatter all the
    waves in the same proportion. If they be not—and a little reflection
    will make it clear to you that they are not—the production of color
    must be an incident of the scattering. Largeness is a thing of
    relation; and the smaller the wave the greater is the relative size
    of any particle on which the wave impinges, and the greater also the
    ratio of the reflected portion to the total wave.

    A pebble placed in the way of the ring-ripples produced by our heavy
    rain-drops on a tranquil pond will throw back a large fraction of
    the ripple incident upon it, while the fractional part of a larger
    wave thrown back by the same pebble might be infinitesimal. Now we
    have already made it clear to our minds that to preserve the solar
    light white, its constituent proportions must not be altered; but in
    the act of division performed by these very small particles we see
    that the proportions _are_ altered; an undue fraction of the smaller
    waves is scattered by the particles, and, as a consequence, in the
    scattered light blue will be the predominant color. The other colors
    of the spectrum must, to some extent, be associated with the blue.
    They are not absent, but deficient. We ought, in fact, to have them
    all, but in diminishing proportions, from the violet to the red.

    We have here presented a case to the imagination, and assuming the
    undulatory theory to be a reality, we have, I think, fairly reasoned
    our way to the conclusion that, were particles, small in comparison
    to the size of the ether waves, sown in our atmosphere, the light
    scattered by those particles would be exactly such as we observe in
    our azure skies. When this light is analyzed all the colors of the
    spectrum are found; but they are found in the proportions indicated
    by our conclusion.

    Let us now turn our attention to the light which passes unscattered
    among the particles. How must it be finally affected? By its
    successive collisions with the particles, the white light is more
    and more robbed of its shorter waves; it therefore loses more and
    more of its due proportion of blue. The result may be anticipated.
    The transmitted light, where short distances are involved, will
    appear yellowish. But as the sun sinks towards the horizon, the
    atmospheric distances increase, and consequently the number of the
    scattering particles. They abstract, in succession, the violet, the
    indigo, the blue, and even disturb the proportions of green. The
    transmitted light under such circumstances must pass from yellow
    through orange to red. This also is exactly what we find in nature.
    Thus, while the reflected light gives us at noon the deep azure of
    the Alpine skies, the transmitted light gives us at sunset the warm
    crimson of the Alpine snows. The phenomena certainly occur _as if_
    our atmosphere were a medium rendered slightly turbid by the
    mechanical suspension of exceedingly small foreign particles.

    Here, as before, we encounter our skeptical “as if.” It is one of
    the parasites of science, ever at hand, and ready to plant itself
    and sprout, if it can, on the weak points of our philosophy. But a
    strong constitution defies the parasite, and in our case, as we
    question the phenomena, probability grows like growing health, until
    in the end the malady of doubt is completely extirpated.

    The first question that naturally arises is, Can small particles be
    really proved to act in the manner indicated? No doubt of it. Each
    one of you can submit the question to an experimental test. Water
    will not dissolve resin, but spirit will, and when spirit which
    holds resin in solution is dropped into water the resin immediately
    separates in solid particles, which render the water milky. The
    coarseness of this precipitate depends on the quantity of the
    dissolved resin. You can cause it to separate in thick clots or in
    exceedingly fine particles. Professor Brücke has given us the
    proportions which produce particles particularly suited to our
    present purpose. One gramme of clean mastic is dissolved in
    eighty-seven grammes of absolute alcohol, and the transparent
    solution is allowed to drop into a beaker containing clear water
    kept briskly stirred. An exceedingly fine precipitate is thus
    formed, which declares its presence by its action upon light.
    Placing a dark surface behind the beaker, and permitting the light
    to fall into it from the top or front, the medium is seen to be
    distinctly blue. It is not, perhaps, so perfect a blue as I have
    seen on exceptional days, this year, among the Alps, but it is a
    very fair sky blue. A trace of soap in water gives a tint of blue.
    London, and I fear Liverpool milk, makes an approximation to the
    same color through the operation of the same cause; and Helmholtz
    has irreverently disclosed the fact that a blue eye is simply a
    turbid medium.

    Numerous instances of the kind might be cited. The action of turbid
    media upon light was fully and beautifully illustrated by Goethe,
    who, though unacquainted with the undulatory theory, was led by his
    experiments to regard the blue of the firmament as caused by an
    illuminated turbid medium with the darkness of space behind it. He
    describes glasses showing a bright yellow by transmitted, and a
    beautiful blue by reflected light. Professor Stokes, who was
    probably the first to discern the real nature of the action of small
    particles on the waves of ether, describes a glass of a similar
    kind. What artists call “chill” is no doubt an effect of this
    description. Through the action of minute particles, the browns of a
    picture often present the appearance of the bloom of a plum. By
    rubbing the varnish with a silk handkerchief optical continuity is
    established and the chill disappears.

    Some years ago I witnessed Mr. Hirst experimenting at Zermatt on the
    turbid water of the Visp, which was charged with the finely divided
    matter ground down by the glaciers. When kept still for a day or so
    the grosser matter sank, but the finer matter remained suspended,
    and gave a distinctly blue tinge to the water. No doubt the blueness
    of certain Alpine lakes is in part due to this cause. Professor
    Roscoe has noticed several striking cases of a similar kind. In a
    very remarkable paper the late Principal Forbes showed that steam
    issuing from the safety valve of a locomotive, when favorably
    observed, exhibits at a certain stage of its condensation the colors
    of the sky. It is blue by reflected light, and orange or red by
    transmitted light. The effect, as pointed out by Goethe, is to some
    extent exhibited by peat smoke.

    More than ten years ago I amused myself at Killarney, by observing
    on a calm day, the straight smoke columns rising from the chimneys
    of the cabins. It was easy to project the lower portion of a column
    against a bright cloud. The smoke in the former case was blue, being
    seen mainly by reflected light; in the latter case it was reddish,
    being seen mainly by transmitted light. Such smoke was not in
    exactly the condition to give us the glow of the Alps, but it was a
    step in this direction. Brücke’s fine precipitate above referred to
    looks yellowish by transmitted light, but by duly strengthening the
    precipitate you may render the white light of noon as ruby colored
    as the sun when seen through Liverpool smoke or upon Alpine
    horizons.

    I do not, however, point to the gross smoke arising from coal as an
    illustration of the action of small particles, because such smoke
    soon absorbs and destroys the waves of blue instead of sending them
    to the eyes of the observer.

    These multifarious facts, and numberless others which cannot now be
    referred to, are explained by reference to the single principle that
    where the scattering particles are small in comparison to the size
    of the waves, we have in the reflected light a greater proportion of
    the smaller waves, and in the transmitted light a greater proportion
    of the larger waves, than existed in the original white light. The
    physiological consequence is that in the one light blue is
    predominant, and in the other light orange or red. And now let us
    push our inquiries forward. Our best microscopes can readily reveal
    objects not more than 1/50000 of an inch in diameter. This is less
    than the length of a wave of red light. Indeed, a first-rate
    microscope would enable us to discern objects not exceeding in
    diameter the length of the smallest waves of the visible spectrum.
    By the microscope, therefore, we can submit our particles to an
    experimental test. If they are as large as the light-waves they will
    infallibly be seen; and if they are not seen it is because they are
    smaller.

    I placed in the hands of our president a bottle containing Brücke’s
    particles in greater number and coarseness than those examined by
    Brücke himself. The liquid was a milky blue, and Mr. Huxley applied
    to it his highest microscopic power. He satisfied me at the time
    that had particles of even 1/100000 of an inch in diameter existed
    in the liquid they could not have escaped detection. But no
    particles were seen. Under the microscope the turbid liquid was not
    to be distinguished from distilled water. Brücke, I may say, also
    found the particles to be of ultra microscopic magnitude.

    But we have it in our power to imitate far more closely than we have
    hitherto done the natural conditions of this problem. We can
    generate in air, as many of you know, artificial skies, and prove
    their perfect identity with the natural one as regards the
    exhibition of a number of wholly unexpected phenomena. By a
    continuous process of growth, moreover, we are able to connect sky
    matter, if I may use the term, with molecular matter on the one
    side, and with molar matter, or matter in sensible masses, on the
    other.

    In illustration of this, I will take an experiment described by M.
    Morren, of Marseilles, at the last meeting of the British
    Association. Sulphur and oxygen combine to form sulphurous acid gas.
    It is this choking gas that is smelt when a sulphur match is burnt
    in air. Two atoms of oxygen and one of sulphur constitute the
    molecule of sulphurous acid. Now it has been recently shown in a
    great number of instances that waves of ether issuing from a strong
    source, such as the sun or the electric light, are competent to
    shake asunder the atoms of gaseous molecules. A chemist would call
    this “decomposition” by light; but it behooves us, who are examining
    the power and function of the imagination, to keep constantly before
    us the physical images which we hold to underlie our terms.
    Therefore I say, sharply and definitely, that the components of the
    molecules of sulphurous acid are shaken asunder by the ether waves.
    Enclosing the substance in a suitable vessel, placing it in a dark
    room, and sending through it a powerful beam of light, we at first
    see nothing; the vessel containing the gas is as empty as a vacuum.
    Soon, however, along the track of the beam a beautiful sky-blue
    color is observed, which is due to the liberated particles of
    sulphur. For a time the blue grows more intense; it then becomes
    whitish; and from a whitish blue it passes to a more or less perfect
    white. If the action be continued long enough, we end by filling the
    tube with a dense cloud of sulphur particles, which by the
    application of proper means may be rendered visible.

    Here, then, our ether waves untie the bond of chemical affinity, and
    liberate a body—sulphur—which at ordinary temperatures is a solid,
    and which therefore soon becomes an object of the senses. We have
    first of all the free atoms of sulphur, which are both invisible and
    incompetent to stir the retina sensibly with scattered light. But
    these atoms gradually coalesce and form particles, which grow larger
    by continual accretion until after a minute or two they appear as
    sky matter. In this condition they are invisible themselves, but
    competent to send an amount of wave motion to the retina sufficient
    to produce the firmamental blue. The particles continue, or may be
    caused to continue, in this condition for a considerable time,
    during which no microscope can cope with them. But they continually
    grow larger, and pass by insensible gradations into the state of
    _cloud_, when they can no longer elude the armed eye. Thus, without
    solution of continuity, we start with matter in the molecule, and
    end with matter in the mass, sky matter being the middle term of the
    series of transformations.

    Instead of sulphurous acid we might choose from a dozen other
    substances, and produce the same effect with any of them. In the
    case of some—probably in the case of all—it is possible to preserve
    matter in the skyey condition for fifteen or twenty minutes under
    the continual operation of the light. During these fifteen or twenty
    minutes the particles are constantly growing larger, without ever
    exceeding the size requisite to the production of the celestial
    blue. Now when two vessels are placed before you, each containing
    sky matter, it is possible to state with great distinctness which
    vessel contains the largest particles.

    The eye is very sensitive to differences of light, when, as here,
    the eye is in comparative darkness, and when the quantities of wave
    motion thrown against the retina are small. The larger particles
    declare themselves by the greater whiteness of their scattered
    light. Call now to mind the observation, or effort at observation,
    made by our president when he failed to distinguish the particles of
    resin in Brücke’s medium, and when you have done so follow me. I
    permitted a beam of light to act upon a certain vapor. In two
    minutes the azure appeared, but at the end of fifteen minutes it had
    not ceased to be azure. After fifteen minutes, for example, its
    color and some other phenomena pronounced it to be a blue of
    distinctly smaller particles than those sought for in vain by Mr.
    Huxley. These particles, as already stated, must have been less than
    1/100000 of an inch in diameter.

    And now I want you to submit to your imagination the following
    question: Here are particles which have been growing continually for
    fifteen minutes, and at the end of that time are demonstrably
    smaller than those which defied the microscope of Mr. Huxley. What
    must have been the size of these particles at the beginning of their
    growth? What notion can you form of the magnitude of such particles?
    As the distances of stellar space give us simply a bewildering sense
    of vastness without leaving any distinct impression on the mind, so
    the magnitudes with which we have here to do impress us with a
    bewildering sense of smallness. We are dealing with infinitesimals
    compared with which the test objects of the microscope are literally
    immense.

    From their perviousness to stellar light, and other considerations,
    Sir John Herschel drew some startling conclusions regarding the
    density and weight of comets. You know that these extraordinary and
    mysterious bodies sometimes throw out tails 100,000,000 of miles in
    length, and 50,000 miles in diameter. The diameter of our earth is
    8,000 miles. Both it and the sky, and a good portion of space beyond
    the sky, would certainly be included in a sphere 10,000 miles
    across. Let us fill this sphere with cometary matter, and make it
    our unit of measure. An easy calculation informs us that to produce
    a comet’s tail of the size just mentioned, about 300,000 such
    measures would have to be emptied into space. Now suppose the whole
    of this stuff to be swept together, and suitably compressed, what do
    you suppose its volume would be? Sir John Herschel would probably
    tell you that the whole mass might be carted away at a single effort
    by one of your dray-horses. In fact, I do not know that he would
    require more than a small fraction of a horse-power to remove the
    cometary dust. After this you will hardly regard as monstrous a
    notion I have sometimes entertained concerning the quantity of
    matter in our sky. Suppose a shell, then, to surround the earth at a
    hight above the surface which would place it beyond the grosser
    matter that hangs in the lower regions of the air—say at the hight
    of the Matterhorn or Mont Blanc. Outside this shell we have the deep
    blue firmament. Let the atmospheric space beyond the shell be swept
    clean, and let the sky matter be properly gathered up. What is its
    probable amount? I have sometimes thought that a lady’s portmanteau
    would contain it all. I have thought that even a gentleman’s
    portmanteau—possibly his snuff-box—might take it in. And whether the
    actual sky be capable of this amount of condensation or not, I
    entertain no doubt that a sky quite as vast as ours, and as good in
    appearance, could be formed from a quantity of matter which might be
    held in the hollow of the hand.

    Small in mass, the vastness in point of number of the particles of
    our sky may be inferred from the continuity of its light. It is not
    in broken patches nor at scattered points that the heavenly azure is
    revealed. To the observer on the summit of Mont Blanc the blue is as
    uniform and coherent as if it formed the surface of the most
    close-grained solid. A marble dome would not exhibit a stricter
    continuity. And Mr. Glaisher will inform you that if our
    hypothetical shell were lifted to twice the hight of Mont Blanc
    above the earth’s surface, we should still have the azure overhead.
    Everywhere through the atmosphere those sky particles are strewn.
    They fill the Alpine valleys, spreading like a delicate gauze in
    front of the slopes of pine. They sometimes so swathe the peaks with
    light as to abolish their definition. This year I have seen the
    Weisshorn thus dissolved in opalescent air.

    By proper instruments the glare thrown from the sky particles
    against the retina may be quenched, and then the mountain which it
    obliterated starts into sudden definition. Its extinction in front
    of a dark mountain resembles exactly the withdrawal of a veil. It is
    the light then taking possession of the eye, and not the particles
    acting as opaque bodies, that interfere with the definition.

    By day this light quenches the stars; even by moonlight it is able
    to exclude from vision all stars between the fifth and the eleventh
    magnitude. It may be likened to a noise, and the stellar radiance to
    a whisper drowned by the noise. What is the nature of the particles
    which shed this light? On points of controversy I will not here
    enter, but I may say that De la Rive ascribes the haze of the Alps
    in fine weather to floating organic germs. Now the possible
    existence of germs in such profusion has been held up as an
    absurdity. It has been affirmed that they would darken the air, and
    on the assumed impossibility of their existence in the requisite
    numbers, without invasion of the solar light, a powerful argument
    has been based by believers in spontaneous generation.

    Similar arguments have been used by the opponents of the germ theory
    of epidemic disease, and both parties have triumphantly challenged
    an appeal to the microscope and the chemist’s balance to decide the
    question. Without committing myself in the least to De la Rive’s
    notion, without offering any objection here to the doctrine of
    spontaneous generation, without expressing any adherence to the germ
    theory of disease, I would simply draw attention to the fact that in
    the atmosphere we have particles which defy both the microscope and
    the balance, which do not darken the air, and which exist,
    nevertheless, in multitudes sufficient to reduce to insignificance
    the Israelitish hyperbole regarding the sands upon the seashore.

    The varying judgments of men on these and other questions may
    perhaps be, to some extent, accounted for by that doctrine of
    relativity which plays so important a part in philosophy. This
    doctrine affirms that the impressions made upon us by any
    circumstance, or combination of circumstances, depends upon our
    previous state. Two travelers upon the same peak, the one having
    ascended to it from the plain, the other having descended to it from
    a higher elevation, will be differently affected by the scene around
    them. To the one nature is expanding, to the other it is
    contracting, and feelings are sure to differ which have two such
    different antecedent states.

    In our scientific judgments the law of relativity may also play an
    important part. To two men, one educated in the school of the
    senses, who has mainly occupied himself with observation, and the
    other educated in the school of imagination as well, and exercised
    in the conception of atoms and molecules to which we have so
    frequently referred, a bit of matter, say 1/50000 of an inch in
    diameter, will present itself differently. The one descends to it
    from his molar hights, the other climbs to it from his molecular
    lowlands. To the one it appears small, to the other large. So also
    as regards the appreciation of the most minute forms of life
    revealed by the microscope. To one of these men they naturally
    appear conterminous with the ultimate particles of matter, and he
    readily figures the molecules from which they directly spring; with
    him there is but a step from the atom to the organism. The other
    discerns numberless organic gradations between both. Compared with
    his atoms, the smallest vibrios and bacteria of the microscopic
    field are as behemoth and leviathan.

    The law of relativity may to some extent explain the different
    attitudes of these two men with regard to the question of
    spontaneous generation. An amount of evidence which satisfies the
    one entirely fails to satisfy the other; and while to the one the
    last bold defense and startling expansion of the doctrine will
    appear perfectly conclusive, to the other it will present itself as
    imposing a profitless labor of demolition on subsequent
    investigators. The proper and possible attitude of these two men is
    that each of them should work as if it were his aim and object to
    establish the view entertained by the other.

    I trust, Mr. President, that you—whom untoward circumstances have
    made a biologist, but who still keep alive your sympathy with that
    class of inquiries which nature intended you to pursue and
    adorn—will excuse me to your brethren if I say that some of them
    seem to form an inadequate estimate of the distance which separates
    the microscopic from the molecular limit, and that, as a
    consequence, they sometimes employ a phraseology which is calculated
    to mislead.

    When, for example, the contents of a cell are described as perfectly
    homogeneous, as absolutely structureless, because the microscope
    fails to distinguish any structure, then I think the microscope
    begins to play a mischievous part. A little consideration will make
    it plain to all of you that the microscope can have no voice in the
    real question of germ structure. Distilled water is more perfectly
    homogeneous than the contents of any possible organic germ. What
    causes the liquid to cease contracting at 39° F., and to grow bigger
    until it freezes? It is a structural process of which the microscope
    can take no note, nor is it likely to do so by any conceivable
    extension of its powers. Place this distilled water in the field of
    an electro-magnet, and bring a microscope to bear upon it. Will any
    change be observed when the magnet is excited? Absolutely none; and
    still profound and complex changes have occurred.

    First of all, the particles of water are rendered diamagnetically
    polar; and secondly, in virtue of the structure impressed upon it by
    the magnetic strain of its molecules, the liquid twists a ray of
    light in a fashion perfectly determinate both as to quantity and
    direction. It would be immensely interesting to both you and me if
    one here present, who has brought his brilliant imagination to bear
    upon this subject, could make us see as he sees the entangled
    molecular processes involved in the rotation of the plane of
    polarization by magnetic force. While dealing with this question he
    lived in a world of matter and of motion to which the microscope has
    no passport, and in which it can offer no aid. The cases in which
    similar conditions hold are simply numberless. Have the diamond, the
    amethyst, and the countless other crystals formed in the
    laboratories of nature and of man, no structure? Assuredly they
    have, but what can the microscope make of it? Nothing. It cannot be
    too distinctly borne in mind that between the microscopic limit and
    the true molecular limit there is room for infinite permutations and
    combinations. It is in this region that the poles of the atoms are
    arranged, that tendency is given to their powers, so that when these
    poles and powers have free action and proper stimulus in a suitable
    environment, they determine first the germ and afterwards the
    complete organism. This first marshaling of the atoms on which all
    subsequent action depends baffles a keener power than that of the
    microscope. Through pure excess of complexity, and long before
    observation can have any voice in the matter, the most highly
    trained intellect, the most refined and disciplined imagination,
    retires in bewilderment from the contemplation of the problem. We
    are struck dumb by an astonishment which no microscope can relieve,
    doubting not only the power of our instrument, but even whether we
    ourselves possess the intellectual elements which will ever enable
    us to grapple with the ultimate structural energies of nature.

    But the speculative faculty, of which imagination forms so large a
    part, will nevertheless wander into regions where the hope of
    certainty would seem to be entirely shut out. We think that though
    the detailed analysis may be, and may ever remain, beyond us,
    general notions may be attainable. At all events, it is plain that
    beyond the present outposts of microscopic inquiry lies an immense
    field for the exercise of the imagination. It is only, however, the
    privileged spirits who know how to use their liberty without abusing
    it, who are able to surround imagination by the firm frontiers of
    reason, that are likely to work with any profit here. But freedom to
    them is of such paramount importance that, for the sake of securing
    it, a good deal of wildness on the part of weaker brethren may be
    overlooked. In more senses than one Mr. Darwin has drawn heavily
    upon the scientific tolerance of his age. He has drawn heavily upon
    _time_ in his development of species, and he has drawn adventurously
    upon _matter_ in his theory of pan-genesis. According to this
    theory, a germ already microscopic is a world of minor germs. Not
    only is the organism as a whole wrapped up in the germ, but every
    organ of the organism has there its special seed.

    This, I say, is an adventurous draft on the power of matter to
    divide itself and distribute its forces. But, unless we are
    perfectly sure that he is overstepping the bounds of reason, that he
    is unwittingly sinning against observed fact or demonstrated law—for
    a mind like that of Darwin can never sin wittingly against either
    fact or law—we ought, I think, to be cautious in limiting his
    intellectual horizon. If there be the least doubt in the matter, it
    ought to be given in favor of the freedom of such a mind. To it a
    vast possibility is in itself a dynamic power, though the
    possibility may never be drawn upon.

    It gives me pleasure to think that the facts and reasonings of this
    discourse tend rather towards the justification of Mr. Darwin than
    towards his condemnation, that they tend rather to augment than to
    diminish the cubic space demanded by this soaring speculator; for
    they seem to show the perfect competence of matter and force, as
    regards divisibility and distribution, to bear the heaviest strain
    that he has hitherto imposed upon them.

    In the case of Mr. Darwin, observation, imagination, and reason
    combined have run back with wonderful sagacity and success over a
    certain length of the line of biological succession. Guided by
    analogy, in his “Origin of Species” he placed as the root of life a
    primordial germ, from which he conceived the amazing richness and
    variety of the life that now is upon the earth’s surface, might be
    deduced. If this were true it would not be final. The human
    imagination would infallibly look behind the germ, and inquire into
    the history of its genesis.

    Certainty is here hopeless, but the materials for an opinion may be
    attainable. In this dim twilight of speculation the inquirer
    welcomes every gleam, and seeks to augment his light by indirect
    incidences. He studies the methods of nature in the ages and the
    worlds within his reach, in order to shape the course of imagination
    in the antecedent ages and worlds. And though the certainty
    possessed by experimental inquiry is here shut out, the imagination
    is not left entirely without guidance. From the examination of the
    solar system, Kant and Laplace came to the conclusion that its
    various bodies once formed parts of the same undislocated mass; that
    matter in a nebulous form preceded matter in a dense form; that as
    the ages rolled away heat was wasted, condensation followed, planets
    were detached, and that finally the chief portion of the fiery cloud
    reached, by self-compression, the magnitude and density of our sun.
    The earth itself offers evidence of a fiery origin; and in our day
    the hypothesis of Kant and Laplace receives the independent
    countenance of spectrum analysis, which proves the same substances
    to be common to the earth and sun. Accepting some such view of the
    construction of our system as probable, a desire immediately arises
    to connect the present life of our planet with the past. We wish to
    know something of our remotest ancestry.

    On its first detachment from the central mass, life, as we
    understand it, could hardly have been present on the earth. How then
    did it come there? The thing to be encouraged here is a reverent
    freedom—a freedom preceded by the hard discipline which checks
    licentiousness in speculation—while the thing to be repressed, both
    in science and out of it, is dogmatism. And here I am in the hands
    of the meeting—willing to end, but ready to go on. I have no right
    to intrude upon you, unasked, the unformed notions which are
    floating like clouds or gathering to more solid consistency in the
    modern speculative scientific mind. But if you wish me to speak
    plainly, honestly, and undisputatiously, I am willing to do so. On
    the present occasion

                  You are ordained to call, and I to come.

    Two views, then, offer themselves to us. Life was present
    potentially in matter when in the nebulous form, and was unfolded
    from it by the way of natural development, or it is a principle
    inserted into matter at a later date. With regard to the question of
    time, the views of men have changed remarkably in our day and
    generation; and I must say as regards courage also, and a manful
    willingness to engage in open contest, with fair weapons, a great
    change has also occurred.

    The clergy of England—at all events the clergy of London—have nerve
    enough to listen to the strongest views which any one amongst us
    would care to utter; and they invite, if they do not challenge, men
    of the most decided opinions to state and stand by those opinions in
    open court. No theory upsets them. Let the most destructive
    hypothesis be stated only in the language current among gentlemen,
    and they look it in the face. They forego alike the thunders of
    heaven and the terrors of the other place, smiting the theory, if
    they do not like it, with honest secular strength. In fact, the
    greatest cowards of the present day are not to be found among the
    clergy, but within the pale of science itself.

    Two or three years ago in an ancient London college—a clerical
    institution—I heard a very remarkable lecture by a very remarkable
    man. Three or four hundred clergymen were present at the lecture.
    The orator began with the civilization of Egypt in the time of
    Joseph; pointing out that the very perfect organization of the
    kingdom, and the possession of chariots, in one of which Joseph
    rode, indicated a long antecedent period of civilization. He then
    passed on to the mud of the Nile, its rate of augmentation, its
    present thickness, and the remains of human handiwork found therein;
    thence to the rocks which bound the Nile valley, and which team with
    organic remains. Thus, in his own clear and admirable way, he caused
    the idea of the world’s age to expand itself indefinitely before the
    mind of his audience, and he contrasted this with the age usually
    assigned to the world.

    During his discourse he seemed to be swimming against a stream; he
    manifestly thought that he was opposing a general conviction. He
    expected resistance; so did I. But it was all a mistake; there was
    no adverse current, no opposing conviction, no resistance, merely
    here and there a half humorous but unsuccessful attempt to entangle
    him in his talk. The meeting agreed with all that had been said
    regarding the antiquity of the earth and of its life. They had,
    indeed, known it all long ago, and they good-humoredly rallied the
    lecturer for coming amongst them with so stale a story. It was quite
    plain that this large body of clergymen, who were, I should say, the
    finest samples of their class, had entirely given up the ancient
    landmarks, and transported the conception of life’s origin to an
    indefinitely distant past.

    In fact, clergymen, if I might be allowed a parenthesis to say so,
    have as strong a leaning towards scientific truth as other men, only
    the resistance to this bent—a resistance due to education—is
    generally stronger in their case than in others. They do not lack
    the positive element, namely, the love of truth, but the negative
    element, the fear of error, preponderates.

    The strength of an electric current is determined by two things—the
    electro-motive force, and the resistance that force has to overcome.
    A fraction, with the former as numerator and the latter as
    denominator, expresses the current-strength. The “current-strength”
    of the clergy towards science may also be expressed by making the
    positive element just referred to the numerator, and the negative
    one the denominator of a fraction. The numerator is not zero nor is
    it even small, but the denominator is large; and hence the current
    strength is such as we find it to be. Slowness of conception, even
    open hostility, may be thus accounted for. They are for the most
    part errors of judgment, and not sins against truth. To most of us
    it may appear very simple, but to a few of us it appears
    transcendently wonderful, that in all classes of society truth
    should have this power and fascination. From the countless
    modifications that life has undergone through natural selection and
    the integration of infinitesimal steps, emerges finally the grand
    result that the strength of truth is greater than the strength of
    error, and that we have only to make the truth clear to the world to
    gain the world to our side. Probably no one wonders more at this
    result than the propounder of the law of natural selection himself.
    Reverting to an old acquaintance of ours, it would seem, on purely
    scientific grounds, as if a Veracity were at the heart of things; as
    if, after ages of latent working, it had finally unfolded itself in
    the life of man; as if it were still destined to unfold itself,
    growing in girth, throwing out stronger branches and thicker leaves,
    and tending more and more by its overshadowing presence to starve
    the weeds of error from the intellectual soil.

    But this is parenthetical; and the gist of our present inquiry
    regarding the introduction of life is this: Does it belong to what
    we call matter, or is it an independent principle inserted into
    matter at some suitable epoch—say when the physical conditions
    become such as to permit of the development of life? Let us put the
    question with all the reverence due to a faith and culture in which
    we all were cradled—a faith and culture, moreover, which are the
    undeniable historic antecedents of our present enlightenment. I say,
    let us put the question reverently, but let us also put it clearly
    and definitely.

    There are the strongest grounds for believing that during a certain
    period of its history the earth was not, nor was it fit to be, the
    theater of life. Whether this was ever a nebulous period, or merely
    a molten period, does not much matter; and if we revert to the
    nebulous condition, it is because the probabilities are really on
    its side. Our question is this: Did creative energy pause until the
    nebulous matter had condensed, until the earth had been detached,
    until the solar fire had so far withdrawn from the earth’s vicinity
    as to permit a crust to gather round a planet? Did it wait until the
    air was isolated, until the seas were formed, until evaporation,
    condensation, and the descent of rain had begun, until the eroding
    forces of the atmosphere had weathered and decomposed the molten
    rocks so as to form soils, until the sun’s rays had become so
    tempered by distance and by waste as to be chemically fit for the
    decompositions necessary to vegetable life? Having waited through
    those æons until the proper conditions had set in, did it send the
    fiat forth, “Let life be!”? These questions define a hypothesis not
    without its difficulties, but the dignity of which was demonstrated
    by the nobleness of the men whom it sustained.

    Modern scientific thought is called upon to decide between this
    hypothesis and another; and public thought generally will afterwards
    be called upon to do the same. You may, however, rest secure in the
    belief that the hypothesis just sketched can never be stormed, and
    that it is sure, if it yield at all, to yield to a prolonged siege.
    To gain new territory, modern argument requires more time than
    modern arms, though both of them move with greater rapidity than of
    yore.

    But however the convictions of individuals here and there may be
    influenced, the process must be slow and secular which commends the
    rival hypothesis of natural evolution to the public mind. For what
    are the core and essence of this hypothesis? Strip it naked and you
    stand face to face with the notion that not alone the more ignoble
    forms of animalcular or animal life, not alone the nobler forms of
    the horse and lion, not alone the exquisite and wonderful mechanism
    of the human body, but that the human mind itself—emotion,
    intellect, will, and all their phenomena—were once latent in a fiery
    cloud. Surely the mere statement of such a motion is more than a
    refutation. But the hypothesis would probably go even further than
    this. Many who hold it would probably assent to the position that at
    the present moment all our philosophy, all our poetry, all our
    science, and all our art—Plato, Shakespeare, Newton, and Raphael—are
    potential in the fires of the sun.

    We long to learn something of our origin. If the evolution
    hypothesis be correct, even this unsatisfied yearning must have come
    to us across the ages which separate the unconscious primeval mist
    from the consciousness of to-day. I do not think that any holder of
    the evolution hypothesis would say that I overstate it or overstrain
    it in any way. I merely strip it of all vagueness, and bring before
    you, unclothed and unvarnished, the notions by which it must stand
    or fall.

    Surely these notions represent an absurdity too monstrous to be
    entertained by any sane mind. Let us, however, give them fair play.
    Let us steady ourselves in front of the hypothesis, and, dismissing
    all terror and excitement from our minds, let us look firmly into it
    with the hard, sharp eye of intellect alone. Why are these notions
    absurd, and why should sanity reject them? The law of relativity, of
    which we have previously spoken, may find its application here.
    These evolution notions are absurd, monstrous, and fit only for the
    intellectual gibbet in relation to the ideas concerning matter which
    were drilled into us when young. Spirit and matter have ever been
    presented to us in the rudest contrast, the one as all noble, the
    other as all vile. But is this correct? Does it represent what our
    mightiest spiritual teacher would call the eternal fact of the
    universe? Upon the answer to this question all depends.

    Supposing, instead of having the foregoing antithesis of spirit and
    matter presented to our youthful minds, we had been taught to regard
    them as equally worthy and equally wonderful; to consider them, in
    fact, as two opposite faces of the self-same mystery. Supposing that
    in youth we had been impregnated with the notion of the poet Goethe,
    instead of the notion of the poet Young, looking at matter, not as
    brute matter, but as “the living garment of God;” do you not think
    that under these altered circumstances the law of relativity might
    have had an outcome different from its present one? Is it not
    probable that our repugnance to the idea of primeval union between
    spirit and matter might be considerably abated? Without this total
    revolution of the notions now prevalent the evolution hypothesis
    must stand condemned; but in many profoundly thoughtful minds such a
    revolution has already taken place. They degrade neither member of
    the mysterious duality referred to; but they exalt one of them from
    its abasement, and repeal the divorce hitherto existing between
    both. In substance, if not in words, their position as regards
    spirit and matter is: “What God hath joined together let not man put
    asunder.”

    I have thus led you to the outer rim of speculative science, for
    beyond the nebula scientific thought has never ventured hitherto,
    and have tried to state that which I considered ought, in fairness,
    to be outspoken. I do not think this evolution hypothesis is to be
    flouted away contemptuously; I do not think it is to be denounced as
    wicked. It is to be brought before the bar of disciplined reason,
    and there justified or condemned. Let us hearken to those who wisely
    support it, and to those who wisely oppose it; and let us tolerate
    those, and they are many, who foolishly try to do neither of these
    things.

    The only thing out of place in the discussion is dogmatism on either
    side. Fear not the evolution hypothesis. Steady yourselves in its
    presence upon that faith in the ultimate triumph of truth which was
    expressed by old Gamaliel when he said: “If it be of God, ye cannot
    overthrow it; if it be of man, it will come to naught.” Under the
    fierce light of scientific inquiry this hypothesis is sure to be
    dissipated if it possess not a core of truth. Trust me, its
    existence as an hypothesis in the mind is quite compatible with the
    simultaneous existence of all those virtues to which the term
    Christian has been applied. It does not solve—it does not profess to
    solve—the ultimate mystery untouched. At bottom it does nothing more
    than “transport the conception of life’s origin to an indefinitely
    distant past.”

    For, granting the nebula and its potential life, the question,
    whence came they? would still remain to baffle and bewilder us. And
    with regard to the ages of forgetfulness which lie between the
    conscious life of the nebula and the conscious life of the earth, it
    is but an extension of that forgetfulness which preceded the birth
    of us all. Those who hold the doctrine of evolution are by no means
    ignorant of the uncertainty of their data, and they yield no more to
    it than a provisional assent. They regard the nebular hypothesis as
    probable, and in the utter absence of any evidence to prove the act
    illegal, they extend the method of nature from the present into the
    past. Here the observed uniformity of nature is their only guide.
    Within the long range of physical inquiry they have never discerned
    in nature the insertion of caprice. Throughout this range the laws
    of physical and intellectual continuity have run side by side.
    Having thus determined the elements of their curve in this world of
    observation and experiment, they prolong that curve into an
    antecedent world, and accept as probable the unbroken sequence of
    development from the nebula to the present time.

    You never hear the really philosophical defenders of the doctrine of
    uniformity speaking of _impossibilities_ in nature. They never say,
    what they are constantly charged with saying, that it is impossible
    for the builder of the universe to alter His work. Their business is
    not with the possible, but the actual; not with a world which
    _might_ be, but with a world which _is_. This they explore with a
    courage not unmixed with reverence, and according to methods which,
    like the quality of a tree, are tested by their fruits. They have
    but one desire—to know the truth. They have but one fear—to believe
    a lie. And if they know the strength of science, and rely upon it
    with unswerving trust, they also know the limits beyond which
    science ceases to be strong. They best know that questions offer
    themselves to thought which science, as now prosecuted, has not even
    the tendency to solve. They keep such questions open, and will not
    tolerate any unlawful limitation of the horizon of their souls. They
    have as little fellowship with the atheist who says there is no God
    as with the theist who professes to know the mind of God.

    “Two things,” said Immanuel Kant, “fill me with awe: the starry
    heavens and the sense of moral responsibility in man.” And in his
    hours of health and strength and sanity, when the stroke of action
    has ceased and the pause of reflection has set in, the scientific
    investigator finds himself overshadowed by the same awe. Breaking
    contact with the hampering details of earth, it associates him with
    a power which gives fulness and tone to his existence, but which he
    can neither analyze nor comprehend.


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    ● Transcriber’s Notes:
       ○ The first 44 footnotes are gathered together in the “NOTES AND
         REFERENCES” section. The following footnotes appear in the text
         where they are referenced.
       ○ The mid dot—“·” is used in numbers to separate the whole part
         from the decimal fraction of the number.
       ○ Missing or obscured punctuation was silently corrected.
       ○ Typographical errors were silently corrected.
       ○ Inconsistent spelling and hyphenation were made consistent only
         when a predominant form was found in this book.
       ○ Text that was in italics is enclosed by underscores
         (_italics_).
       ○ The use of a caret (^) before a letter, or letters, shows that
         the following letter or letters was intended to be a
         superscript, as in S^t Bartholomew or 10^{th} Century.
       ○ Superscripts are used to indicate numbers raised to a power. In
         this plain text document, they are represented by characters
         like this: “MV^2” or “10^{18}”, i.e. MV squared or 10 to the
         18th power.