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Darwiniana by Thomas Henry Huxley

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discusses the very question at issue in a passage which is well worth
reading (vol. i. p. 87), and also comes to a conclusion opposed to Mr.
Mivart's axiom. A proposition which has been so much disputed and
repudiated, should, under no circumstances, have been thus confidently
assumed to be true. For myself, I utterly reject it, inasmuch as the
logical consequence of the adoption of any such principle is the denial of
all moral value to sympathy and affection. According to Mr. Mivart's axiom,
the man who, seeing another struggling in the water, leaps in at the risk
of his own life to save him, does that which is "destitute of the most
incipient degree of real goodness," unless, as he strips off his coat, he
says to himself, "Now, mind, I am going to do this because it is my duty
and for no other reason;" and the most beautiful character to which
humanity can attain, that of the man who does good without thinking about
it, because he loves justice and mercy and is repelled by evil, has no
claim on our moral approbation. The denial that a man acts morally because
he does not think whether he does so or not, may be put upon the same
footing as the denial of the title of an arithmetician to the calculating
boy, because he did not know how he worked his sums. If mankind ever
generally accept and act upon Mr. Mivart's axiom, they will simply become a
set of most unendurable prigs; but they never have accepted it, and I
venture to hope that evolution has nothing so terrible in store for the
human race.

But if an action, the motive of which is nothing but affection or sympathy,
may be deserving of moral approbation and really good, who that has ever
had a dog of his own will deny that animals are capable of such actions?
Mr. Mivart indeed says:--"It may be safely affirmed, however, that there is
no trace in brutes of any actions simulating morality which are not
explicable by the fear of punishment, by the hope of pleasure, or by
personal affection" (p. 221). But it may be affirmed, with equal truth,
that there is no trace in men of any actions which are not traceable to the
same motives. If a man does anything, he does it either because he fears to
be punished if he does not do it, or because he hopes to obtain pleasure by
doing it, or because he gratifies his affections [Footnote: In separating
pleasure and the gratification of affection, I simply follow Mr. Mivart
without admitting the justice of the separation.] by doing it.

Assuming the position of the absolute moralists, let it be granted that
there is a perception of right and wrong innate in every man. This means,
simply, that when certain ideas are presented to his mind, the feeling of
approbation arises; and when certain others, the feeling of disapprobation.
To do your duty is to earn the approbation of your conscience, or moral
sense; to fail in your duty is to feel its disapprobation, as we all say.
Now, is approbation a pleasure or a pain? Surely a pleasure. And is
disapprobation a pleasure or a pain? Surely a pain. Consequently, all that
is really meant by the absolute moralists is that there is, in the very
nature of man, something which enables him to be conscious of these
particular pleasures and pains. And when they talk of immutable and eternal
principles of morality, the only intelligible sense which I can put upon
the words, is that the nature of man being what it is, he always has been,
and always will be, capable of feeling these particular pleasures and
pains. _À priori,_ I have nothing to say against this proposition.
Admitting its truth, I do not see how the moral faculty is on a different
footing from any of the other faculties of man. If I choose to say that it
is an immutable and eternal law of human nature that "ginger is hot in the
mouth," the assertion has as much foundation of truth as the other, though
I think it would be expressed in needlessly pompous language. I must
confess that I have never been able to understand why there should be such
a bitter quarrel between the intuitionists and the utilitarians. The
intuitionist is, after all, only a utilitarian who believes that a
particular class of pleasures and pains has an especial importance, by
reason of its foundation in the nature of man, and its inseparable
connection with his very existence as a thinking being. And as regards the
motive of personal affection: Love, as Spinoza profoundly says, is the
association of pleasure with that which is loved. [Footnote: "Nempe, Amor
nihil aliud est, quam Lætitia, concomitante idea causæ
externæ."--_Ethices_, III. xiii.] Or, to put it to the common sense of
mankind, is the gratification of affection a pleasure or a pain? Surely a
pleasure. So that whether the motive which leads us to perform an action is
the love of our neighbour, or the love of God, it is undeniable that
pleasure enters into that motive.

Thus much in reply to Mr. Mivart's arguments. I cannot but think that it is
to be regretted that he ekes them out by ascribing to the doctrines of the
philosophers with whom he does not agree, logical consequences which have
been over and over again proved not to flow from them: and when reason
fails him, tries the effect of an injurious nickname. According to the
views of Mr. Spencer, Mr. Mill, and Mr. Darwin, Mr. Mivart tells us,
"_virtue is a mere kind of retrieving:_" and, that we may not miss the
point of the joke, he puts it in italics. But what if it is? Does that make
it less virtue? Suppose I say that sculpture is a "mere way" of
stone-cutting, and painting a "mere way" of daubing canvas, and music a
"mere way" of making a noise, the statements are quite true; but they only
show that I see no other method of depreciating some of the noblest aspects
of humanity than that of using language in an inadequate and misleading
sense about them. And the peculiar inappropriateness of this particular
nickname to the views in question, arises from the circumstance which Mr.
Mivart would doubtless have recollected, if his wish to ridicule had not
for the moment obscured his judgment--that whether the law of evolution
applies to man or not, that of hereditary transmission certainly does. Mr.
Mivart will hardly deny that a man owes a large share of the moral
tendencies which he exhibits to his ancestors; and the man who inherits a
desire to steal from a kleptomaniac, or a tendency to benevolence from a
Howard, is, so far as he illustrates hereditary transmission, comparable to
the dog who inherits the desire to fetch a duck out of the water from his
retrieving sire. So that, evolution, or no evolution, moral qualities are
comparable to a "kind of retrieving;" though the comparison, if meant for
the purposes of casting obloquy on evolution, does not say much for the
fairness of those who make it.

The Quarterly Reviewer and Mr. Mivart base their objections to the
evolution of the mental faculties of man from those of some lower animal
form upon what they maintain to be a difference in kind between the mental
and moral faculties of men and brutes; and I have endeavoured to show, by
exposing the utter unsoundness of their philosophical basis, that these
objections are devoid of importance.

The objections which Mr. Wallace brings forward to the doctrine of the
evolution of the mental faculties of man from those of brutes by natural
causes, are of a different order, and require separate consideration.

If I understand him rightly, he by no means doubts that both the bodily and
the mental faculties of man have been evolved from those of some lower
animal; but he is of opinion that some agency beyond that which has been
concerned in the evolution of ordinary animals has been operative in the
case of man. "A superior intelligence has guided the development of man in
a definite direction and for a special purpose, just as man guides the
development of many animal and vegetable forms." [Footnote: "The Limits of
Natural Selection as applied to Man" (_loc. cit._ p. 359).] I
understand this to mean that, just as the rock-pigeon has been produced by
natural causes, while the evolution of the tumbler from the blue rock has
required the special intervention of the intelligence of man, so some
anthropoid form may have been evolved by variation and natural selection;
but it could never have given rise to man, unless some superior
intelligence had played the part of the pigeon-fancier.

According to Mr. Wallace, "whether we compare the savage with the higher
developments of man, or with the brutes around him, we are alike driven to
the conclusion, that, in his large and well-developed brain, he possesses
an organ quite disproportioned to his requirements" (p. 343); and he asks,
"What is there in the life of the savage but the satisfying of the cravings
of appetite in the simplest and easiest way? What thoughts, idea, or
actions are there that raise him many grades above the elephant or the
ape?" (p. 342.) I answer Mr. Wallace by citing a remarkable passage which
occurs in his instructive paper on "Instinct in Man and Animals."

"Savages make long journeys in many directions, and, their whole faculties
being directed to the subject, they gain a wide and accurate knowledge of
the topography, not only of their own district, but of all the regions
round about. Every one who has travelled in a new direction communicates
his knowledge to those who have travelled less, and descriptions of routes
and localities, and minute incidents of travel, form one of the main
staples of conversation around the evening fire. Every wanderer or captive
from another tribe adds to the store of information, and, as the very
existence of individuals and of whole families and tribes depends upon the
completeness of this knowledge, all the acute perceptive faculties of the
adult savage are directed to acquiring and perfecting it. The good hunter
or warrior thus comes to know the bearing of every hill and mountain range,
the directions and junctions of all the streams, the situation of each
tract characterised by peculiar vegetation, not only within the area he has
himself traversed, but perhaps for a hundred miles around it. His acute
observation enables him to detect the slightest undulations of the surface,
the various changes of subsoil and alterations in the character of the
vegetation that would be quite imperceptible to a stranger. His eye is
always open to the direction in which he is going; the mossy side of trees,
the presence of certain plants under the shade of rocks, the morning and
evening flight of birds, are to him indications of direction almost as sure
as the sun in the heavens" (pp. 207, 208).

I have seen enough of savages to be able to declare that nothing can be
more admirable than this description of what a savage has to learn. But it
is incomplete. Add to all this the knowledge which a savage is obliged to
gain of the properties of plants, of the characters and habits of animals,
and of the minute indications by which their course is discoverable:
consider that even an Australian can make excellent baskets and nets, and
neatly fitted and beautifully balanced spears; that he learns to use these
so as to be able to transfix a quartern loaf at sixty yards; and that very
often, as in the case of the American Indians, the language of a savage
exhibits complexities which a well-trained European finds it difficult to
master: consider that every time a savage tracks his game he employs a
minuteness of observation, and an accuracy of inductive and deductive
reasoning which, applied to other matters, would assure some reputation to
a man of science, and I think we need ask no further why he possesses such
a fair supply of brains. In complexity and difficulty, I should say that
the intellectual labour of a "good hunter or warrior" considerably exceeds
that of an ordinary Englishman. The Civil Service Examiners are held in
great terror by young Englishmen; but even their ferocity never tempted
them to require a candidate to possess such a knowledge of a parish as Mr.
Wallace justly points out savages may possess of an area a hundred miles or
more in diameter.

But suppose, for the sake of argument, that a savage has more brains than
seems proportioned to his wants, all that can be said is that the objection
to natural selection, if it be one, applies quite as strongly to the lower
animals. The brain of a porpoise is quite wonderful for its mass, and for
the development of the cerebral convolutions. And yet since we have ceased
to credit the story of Arion, it is hard to believe that porpoises are much
troubled with intellect: and still more difficult is it to imagine that
their big brains are only a preparation for the advent of some accomplished
cetacean of the future. Surely, again, a wolf must have too much brains, or
else how is it that a dog with only the same quantity and form of brain is
able to develop such singular intelligence? The wolf stands to the dog in
the same relation as the savage to the man; and, therefore, if Mr.
Wallace's doctrine holds good, a higher power must have superintended the
breeding up of wolves from some inferior stock, in order to prepare them to
become dogs.

Mr. Wallace further maintains that the origin of some of man's mental
faculties by the preservation of useful variations is not possible. Such,
for example, are "the capacity to form ideal conceptions of space and time,
of eternity and infinity; the capacity for intense artistic feelings of
pleasure in form, colour, and composition; and for those abstract notions
of form and number which render geometry and arithmetic possible." "How,"
he asks, "were all or any of these faculties first developed, when they
could have been of no possible use to man in his early stages of

Surely the answer is not far to seek. The lowest savages are as devoid of
any such conceptions as the brutes themselves. What sort of conceptions of
space and time, of form and number, can be possessed by a savage who has
not got so far as to be able to count beyond five or six, who does not know
how to draw a triangle or a circle, and has not the remotest notion of
separating the particular quality we call form, from the other qualities of
bodies? None of these capacities are exhibited by men, unless they form
part of a tolerably advanced society. And, in such a society, there are
abundant conditions by which a selective influence is exerted in favour of
those persons who exhibit an approximation towards the possession of these

The savage who can amuse his fellows by telling a good story over the
nightly fire, is held by them in esteem and rewarded, in one way or
another, for so doing--in other words, it is an advantage to him to possess
this power. He who can carve a paddle, or the figure-head of a canoe
better, similarly profits beyond his duller neighbour. He who counts a
little better than others, gets most yams when barter is going on, and
forms the shrewdest estimate of the numbers of an opposing tribe. The
experience of daily life shows that the conditions of our present social
existence exercise the most extraordinarily powerful selective influence in
favour of novelists, artists, and strong intellects of all kinds; and it
seems unquestionable that all forms of social existence must have had the
same tendency, if we consider the indisputable facts that even animals
possess the power of distinguishing form and number, and that they are
capable of deriving pleasure from particular forms and sounds. If we admit,
as Mr. Wallace does, that the lowest savages are not raised "many grades
above the elephant and the ape;" and if we further admit, as I contend must
be admitted, that the conditions of social life tend, powerfully, to give
an advantage to those individuals who vary in the direction of intellectual
or æsthetic excellence, what is there to interfere with the belief that
these higher faculties, like the rest, owe their development to natural

Finally, with respect to the development of the moral sense out of the
simple feelings of pleasure and pain, liking and disliking, with which the
lower animals are provided, I can find nothing in Mr. Wallace's reasonings
which has not already been met by Mr. Mill, Mr. Spencer, or Mr. Darwin.

I do not propose to follow the Quarterly Reviewer and Mr. Mivart through
the long string of objections in matters of detail which they bring against
Mr. Darwin's views. Every one who has considered the matter carefully will
be able to ferret out as many more "difficulties"; but he will also, I
believe, fail as completely as they appear to me to have done, in bringing
forward any fact which is really contradictory of Mr. Darwin's views.
Occasionally, too, their objections and criticisms are based upon errors of
their own. As, for example, when Mr. Mivart and the Quarterly Reviewer
insist upon the resemblances between the eyes of _Cephalopoda_ and
_Vertebrata_, quite forgetting that there are striking and altogether
fundamental differences between them; or when the Quarterly Reviewer
corrects Mr. Darwin for saying that the gibbons, "without having been
taught, can walk or run upright with tolerable quickness, though they move
awkwardly, and much less securely than man." The Quarterly Reviewer says,
"This is a little misleading, inasmuch as it is not stated that this
upright progression is effected by placing the enormously long arms behind
the head, or holding them out backwards as a balance in progression."

Now, before carping at a small statement like this, the Quarterly Reviewer
should have made sure that he was quite right. But he happens to be quite
wrong. I suspect he got his notion of the manner in which a gibbon walks
from a citation in "Man's Place in Nature." But at that time I had not seen
a gibbon walk. Since then I have, and I can testify that nothing can be
more precise than Mr. Darwin's statement. The gibbon I saw walked without
either putting his arms behind his head or holding them out backwards. All
he did was to touch the ground with the outstretched fingers of his long
arms now and then, just as one sees a man who carries a stick, but does not
need one, touch the ground with it as he walks along.

Again, a large number of the objections brought forward by Mr. Mivart and
the Quarterly Reviewer apply to evolution in general, quite as much as to
the particular form of that doctrine advocated by Mr. Darwin; or, to their
notions of Mr. Darwin's views and not to what they really are. An excellent
example of this class of difficulties is to be found in Mr. Mivart's
chapter on "Independent Similarities of Structure." Mr. Mivart says that
these cannot be explained by an "absolute and pure Darwinian," but "that an
innate power and evolutionary law, aided by the corrective action of
natural selection, should have furnished like needs with like aids, is not
at all improbable" (p. 82).

I do not exactly know what Mr. Mivart means by an "absolute and pure
Darwinian;" indeed Mr. Mivart makes that creature hold so many singular
opinions that I doubt if I can ever have seen one alive. But I find nothing
in his statement of the view which he imagines to be originated by himself,
which is really inconsistent with what I understand to be Mr. Darwin's

I apprehend that the foundation of the theory of natural selection is the
fact that living bodies tend incessantly to vary. This variation is neither
indefinite, nor fortuitous, nor does it take place in all directions, in
the strict sense of these words.

Accurately speaking, it is not indefinite, nor does it take place in all
directions, because it is limited by the general characters of the type to
which the organism exhibiting the variation belongs. A whale does not tend
to vary in the direction of producing feathers, nor a bird in the direction
of developing whalebone. In popular language there is no harm in saying
that the waves which break upon the sea-shore are indefinite, fortuitous,
and break in all directions. In scientific language, on the contrary, such
a statement would be a gross error, inasmuch as every particle of foam is
the result of perfectly definite forces, operating according to no less
definite laws. In like manner, every variation of a living form, however
minute, however apparently accidental, is inconceivable except as the
expression of the operation of molecular forces or "powers" resident within
the organism. And, as these forces certainly operate according to definite
laws, their general result is, doubtless, in accordance with some general
law which subsumes them all. And there appears to be no objection to call
this an "evolutionary law." But nobody is the wiser for doing so, or has
thereby contributed, in the least degree, to the advance of the doctrine of
evolution, the great need of which is a theory of variation.

When Mr. Mivart tells us that his "aim has been to support the doctrine
that these species have been evolved by ordinary _natural laws_ (for
the most part unknown), aided by the _subordinate_ action of 'natural
selection'" (pp. 332-3), he seems to be of opinion that his enterprise has
the merit of novelty. All I can say is that I have never had the slightest
notion that Mr. Darwin's aim is in any way different from this. If I affirm
that "species have been evolved by variation [Footnote: Including under
this head hereditary transmission.] (a natural process, the laws of which
are for the most part unknown), aided by the subordinate action of natural
selection," it seems to me that I enunciate a proposition which constitutes
the very pith and marrow of the first edition of the "Origin of Species."
And what the evolutionist stands in need of just now, is not an iteration
of the fundamental principle of Darwinism, but some light upon the
questions, What are the limits of variation? and, If a variety has arisen,
can that variety be perpetuated, or even intensified, when selective
conditions are indifferent, or perhaps unfavourable to its existence? I
cannot find that Mr. Darwin has ever been very dogmatic in answering these
questions. Formerly, he seems to have inclined to reply to them in the
negative, while now his inclination is the other way. Leaving aside those
broad questions of theology, philosophy, and ethics, by the discussion of
which neither the Quarterly Reviewer nor Mr. Mivart can be said to have
damaged Darwinism--whatever else they have injured--this is what their
criticisms come to. They confound a struggle for some rifle-pits with an
assault on the fortress.

In some respects, finally, I can only characterise the Quarterly Reviewer's
treatment of Mr. Darwin as alike unjust and unbecoming. Language of this
strength requires justification, and on that ground I add the remarks which

The Quarterly Reviewer opens his essay by a careful enumeration of all
those points upon which, during the course of thirteen years of incessant
labour, Mr. Darwin has modified his opinions. It has often and justly been
remarked, that what strikes a candid student of Mr. Darwin's works is not
so much his industry, his knowledge, or even the surprising fertility of
his inventive genius; but that unswerving truthfulness and honesty which
never permit him to hide a weak place, or gloss over a difficulty, but lead
him, on all occasions, to point out the weak places in his own armour, and
even sometimes, it appears to me, to make admissions against himself which
are quite unnecessary. A critic who desires to attack Mr. Darwin has only
to read his works with a desire to observe, not their merits, but their
defects, and he will find, ready to hand, more adverse suggestions than are
likely ever to have suggested themselves to his own sharpness, without Mr.
Darwin's self-denying aid.

Now this quality of scientific candour is not so common that it needs to be
discouraged; and it appears to me to deserve other treatment than that
adopted by the Quarterly Reviewer, who deals with Mr. Darwin as an Old
Bailey barrister deals with a man against whom he wishes to obtain a
conviction, _per fas aut nefas_, and opens his case by endeavouring to
create a prejudice against the prisoner in the minds of the jury. In his
eagerness to carry out this laudable design, the Quarterly Reviewer cannot
even state the history of the doctrine of natural selection without an
oblique and entirely unjustifiable attempt to depreciate Mr. Darwin. "To
Mr. Darwin," says he, "and (through Mr. Wallace's reticence) to Mr. Darwin
alone, is due the credit of having first brought it prominently forward and
demonstrated its truth." No one can less desire than I do, to throw a doubt
upon Mr. Wallace's originality, or to question his claim to the honour of
being one of the originators of the doctrine of natural selection; but the
statement that Mr. Darwin has the sole credit of originating the doctrine
because of Mr. Wallace's reticence is simply ridiculous. The proof of this
is, in the first place, afforded by Mr. Wallace himself, whose noble
freedom from petty jealousy in this matter smaller folk would do well to
imitate, and who writes thus:--"I have felt all my life, and I still feel,
the most sincere satisfaction that Mr. Darwin had been at work long before
me and that it was not left for me to attempt to write the 'Origin of
Species.' I have long since measured my own strength, and know well that it
would be quite unequal to that task." So that if there was any reticence at
all in the matter, it was Mr. Darwin's reticence during the long twenty
years of study which intervened between the conception and the publication
of his theory, which gave Mr. Wallace the chance of being an independent
discoverer of the importance of natural selection. And, finally, if it be
recollected that Mr. Darwin's and Mr. Wallace's essays were published
simultaneously in the "Journal of the Linnæan Society" for 1858, it follows
that the Reviewer, while obliquely depreciating Mr. Darwin's deserts, has
in reality awarded to him a priority which, in legal strictness, does not

Mr. Mivart, whose opinions so often concur with those of the Quarterly
Reviewer, puts the case in a way, which I much regret to be obliged to say,
is, in my judgment, quite as incorrect; though the injustice may be less
glaring. He says that the theory of natural selection is, in general,
exclusively associated with the name of Mr. Darwin, "on account of the
noble self-abnegation of Mr. Wallace." As I have said, no one can honour
Mr. Wallace more than I do, both for what he has done and for what he has
not done, in his relation to Mr. Darwin. And perhaps nothing is more
creditable to him than his frank declaration that he could not have written
such a work as the "Origin of Species." But, by this declaration, the
person most directly interested in the matter repudiates, by anticipation,
Mr. Mivart's suggestion that Mr. Darwin's eminence is more or less due to
Mr. Wallace's modesty.




In the former half of the eighteenth century, the term "evolution" was
introduced into biological writings, in order to denote the mode in which
some of the most eminent physiologists of that time conceived that the
generations of living things took place; in opposition to the hypothesis
advocated, in the preceding century, by Harvey in that remarkable work
[Footnote: The _Exercitationes de Generatione Animalium_, which Dr.
George Ent extracted from him and published in 1651.] which would give him
a claim to rank among the founders of biological science, even had he not
been the discoverer of the circulation of the blood.

One of Harvey's prime objects is to defend and establish, on the basis of
direct observation, the opinion already held by Aristotle; that, in the
higher animals at any rate, the formation of the new organism by the
process of generation takes place, not suddenly, by simultaneous accretion
of rudiments of all, or of the most important, of the organs of the adult;
nor by sudden metamorphosis of a formative substance into a miniature of
the whole, which subsequently grows; but by _epigenesis_, or
successive differentiation of a relatively homogeneous rudiment into the
parts and structures which are characteristic of the adult.

"Et primò, quidem, quoniam per _epigenesin_ sive partium
superexorientium additamentum pullum fabricari certum est: quænam pars ante
alias omnes exstruatur, et quid de illa ejusque generandi modo observandum
veniat, dispiciemus. Ratum sane est et in ovo manifestè apparet quod
_Aristoteles_ de perfectorum animalium generatione enuntiat: nimirum,
non omnes partes simul fieri, sed ordine aliam post aliam; primùmque
existere particulam genitalem, cujus virtute postea (tanquam ex principio
quodam) reliquæ omnes partes prosiliant. Qualem in plantarum seminibus
(fabis, putà, aut glandibus) gemmam sive apicem protuberantem cernimus,
totius futuræ arboris principium. _Estque hæc particula, velut filius
emancipatus seorsumquc collocatus, et principium per se vivens; unde
postea, membrorum ordo describitur; et quæcunque ad absolvendum animal
pertinent, disponuntur._ [Footnote: _De Generatione Animalium_,
lib. ii. cap. x.] Quoniam enim _nulla pars se ipsam generat; sed postquam
generata est, se ipsam jam auget; ideo eam primùm oriri necesse est, quæ
principium augendi contineat (sive enim planta, sive animal est, æque
omnibus inest quod vim habeat vegetandi, sive nutriendi_), [Footnote:
_De Generatione_, lib. ii. cap. iv.] simulque reliquas omnes partes
suo quamque ordine distinguat et formet; proindeque in eadem primogenita
particula anima primario inest, sensus, motusque, et totius vitæ auctor et
principium." (Exercitatio 51.)

Harvey proceeds to contrast this view with that of the "Medici," or
followers of Hippocrates and Galen, who, "badly philosophising," imagined
that the brain, the heart, and the liver were simultaneously first
generated in the form of vesicles; and, at the same time, while expressing
his agreement with Aristotle in the principle of epigenesis, he maintains
that it is the blood which is the primal generative part, and not, as
Aristotle thought, the heart.

In the latter part of the seventeenth century, the doctrine of epigenesis,
thus advocated by Harvey, was controverted, on the ground of direct
observation, by Malpighi, who affirmed that the body of the chick is to be
seen in the egg, before the _punctum sanguineum_ makes it appearance.
But, from this perfectly correct observation a conclusion which is by no
means warranted was drawn; namely, that the chick, as a whole, really
exists in the egg antecedently to incubation; and that what happens in the
course of the latter process is no addition of new parts, "alias post alias
natas," as Harvey puts it, but a simple expansion, or unfolding, of the
organs which already exist, though they are too small and inconspicuous to
be discovered. The weight of Malpighi's observations therefore fell into
the scale of that doctrine which Harvey terms _metamorphosis_, in
contradistinction to epigenesis.

The views of Malpighi were warmly welcomed, on philosophical grounds, by
Leibnitz, [Footnote: "Cependant, pour revenir aux formes ordinaires ou aux
âmes matérielles, cette durée qu'il leur faut attribuer à la place de celle
qu'on avoit attribuée aux atomes pourroit faire douter si elles ne vont pas
de corps en corps; ce qui seroit la métempsychose, à peu près comme
quelques philosophes ont cru la transmission du mouvement et celle des
espèces. Mais cette imagination est bien éloignée de la nature des choses.
Il n'y a point de tel passage; et c'est ici où les transformations de
Messieurs Swammerdam, Malpighi, et Leewenhoek, qui sont des plus excellens
observateurs de notre tems, sont venues à mon secours, et m'ont fait
admettre plus aisément, que l'animal, et toute autre substance organisée ne
commence point lorsque nous le croyons, et que sa generation apparente
n'est qu'une développement et une espèce d'augmentation. Aussi ai je
remarqué que l'auteur de la _Recherche de la Verité_, M. Regis, M.
Hartsoeker, et d'autres habiles hommes n'ont pas été fort éloignés de ce
sentiment." Leibnitz, _Système Nouveau de la Nature_, 1695. The
doctrine of "Embôitement" is contained in the _Considérations sur le
Principe de Vie_, 1705; the preface to the _Theodicée_, 1710; and
the _Principes de la Nature et de la Grace_ (§ 6), 1718.] who found in
them a support to his hypothesis of monads, and by Malebranche; [Footnote:
"Il est vrai que la pensée la plus raisonnable et la plus conforme à
l'experience sur cette question très difficile de la formation du foetus;
c'est que les enfans sont déja presque tout formés avant même l'action par
laquelle ils sont conçus; et que leurs mères ne font que leur donner
l'accroissement ordinaire dans le temps de la grossesse." _De la
Recherche de la Verité_, livre ii. chap. vii. p. 334, 7th ed., 1721.]
while, in the middle of the eighteenth century, not only speculative
considerations, but a great number of new and interesting observations on
the phenomena of generation, led the ingenious Bonnet, and Haller,
[Footnote: The writer is indebted to Dr. Allen Thomson for reference to the
evidence contained in a note to Haller's edition of Boerhaave's
_Prælectiones Academicæ_, vol. v. pt. ii. p. 497, published in 1744,
that Haller originally advocated epigenesis.] the first physiologist of the
age, to adopt, advocate, and extend them.

Bonnet affirms that, before fecundation, the hen's egg contains an
excessively minute but complete chick; and that fecundation and incubation
simply cause this germ to absorb nutritious matters, which are deposited in
the interstices of the elementary structures of which the miniature chick,
or germ, is made up. The consequence of this intussusceptive growth is the
"development" or "evolution" of the germ into the visible bird. Thus an
organised individual (_tout organisé_) "is a composite body consisting
of the original, or _elementary_, parts and of the matters which have
been associated with them by the aid of nutrition;" so that, if these
matters could be extracted from the individual (_tout_), it would, so
to speak, become concentrated in a point, and would thus be restored to its
primitive condition of a _germ_; "just as by extracting from a bone
the calcareous substance which is the source of its hardness, it is reduced
to its primitive state of gristle or membrane." [Footnote:
_Considérations sur les Corps organisés, chap. x.] "Evolution" and
"development" are, for Bonnet, synonymous terms; and since by "evolution"
he means simply the expansion of that which was invisible into visibility,
he was naturally led to the conclusion, at which Leibnitz had arrived by a
different line of reasoning, that no such thing as generation, in the
proper sense of the word, exists in Nature. The growth of an organic being
is simply a process of enlargement as a particle of dry gelatine may be
swelled up by the intussusception of water; its death is a shrinkage, such
as the swelled jelly might undergo on desiccation. Nothing really new is
produced in the living world, but the germs which develop have existed
since the beginning of things; and nothing really dies, but, when what we
call death takes place, the living thing shrinks back into its germ state.
[Footnote: Bonnet had the courage of his opinions, and in the
_Palingénésie Philosophique_, part vi. chap, iv., he develops a
hypothesis which he terms "évolution naturelle;" and which, making
allowance for his peculiar views of the nature of generation, bears no
small resemblance to what is understood by "evolution" at the present

"Si la volonté divine a créé par un seul Acte l'Universalité des êtres,
d'où venoient ces plantes et ces animaux dont Moyse nous decrit la
Production au troisieme et au cinquieme jour du renouvellement de notre

"Abuserois-je de la liberté de conjectures si je disois, que les Plantes et
les Animaux qui existent aujourd'hui sont parvenus par une sorte
d'evolution naturelle des Etres organises qui peuplaient ce premier Monde,
sorti immédiatement des MAINS du CREATEUR?...

"Ne supposons que trois révolutions. La Terre vient de sortir des MAINS du
CREATEUR. Des causes preparées par sa SAGESSE font développer de toutes
parts les Germes. Les Etres organisés commencent à jouir de l'existence.
Ils étoient probablement alors bien différens de ce qu'ils sont
aujourd'hui. Ils l'etoient autant que ce premier Monde différoit de celui
que nous habitons. Nous manquons de moyens pour juger de ces dissemblances,
et peut-être que le plus habile Naturaliste qui auroit été placé dans ce
premier Monde y auroit entièrement méconnu nos Plantes et nos Animaux."]

The two parts of Bonnet's hypothesis, namely, the doctrine that all living
things proceed from pre-existing germs, and that these contain, one
inclosed within the other, the germs of all future living things, which is
the hypothesis of "_emboîtement_;" and the doctrine that every germ
contains in miniature all the organs of the adult, which is the hypothesis
of evolution or development, in the primary senses of these words, must be
carefully distinguished. In fact, while holding firmly by the former,
Bonnet more or less modified the latter in his later writings, and, at
length, he admits that a "germ" need not be an actual miniature of the
organism; but that it may be merely an "original preformation" capable of
producing the latter. [Footnote: "Ce mot (germe) ne désignera pas seulement
un corps organisé _réduit en petit_; il désignera encore toute espèce
de _préformation originelle dont un Tout organique peut résulter comme de
son principe immédiat."--Palingénésie Philosophique_, part X. chap. II.]

But, thus defined, the germ is neither more nor less than the "particula
genitalis" of Aristotle, or the "primordium vegetale" or "ovum" of Harvey;
and the "evolution" of such a germ would not be distinguishable from

Supported by the great authority of Haller, the doctrine of evolution, or
development, prevailed throughout the whole of the eighteenth century, and
Cuvier appears to have substantially adopted Bonnet's later views, though
probably he would not have gone all lengths in the direction of
"emboîtement." In a well-known note to Laurillard's "Éloge," prefixed to
the last edition of the "Ossemens fossiles," the "radical de l'être" is
much the same thing as Aristotle's "particula genitalis" and Harvey's
"ovum." [Footnote: "M. Cuvier considérant que tous les êtres organisés sont
dérivés de parens, et ne voyant dans la nature aucune force capable de
produire l'organisation, croyait à la pré-existence des germes; non pas à
la pré-existence d'un être tout formé, puisqu'il est bien évident que ce
n'est que par des développemens successifs que l'être acquiert sa forme;
mais, si l'on peut s'exprimer ainsi, à la pré-existence du _radical de
l'être_, radical qui existe avant que la série des évolutions ne
commence, et qui remonte certainement, suivant la belle observation de
Bonnet, à plusieurs generations."--Laurillard, _Éloge de Cuvier_, note

Bonnet's eminent contemporary, Buffon, held nearly the same views with
respect to the nature of the germ, and expresses them even more

"Ceux qui ont cru que le coeur étoit le premier formé, se sont trompés;
ceux qui disent que c'est le sang se trompent aussi: tout est formé en même
temps. Si l'on ne consulte que l'observation, le poulet se voit dans l'oeuf
avant qu'il ait été couvé." [Footnote: _Histoire Naturelle_, tom. ii.
ed. ii. 1750, p. 350.]

"J'ai ouvert une grande quantité d'oeufs à differens temps avant et après
l'incubation, et je me suis convaincu par mes yeux que le poulet existe en
entier dans le milieu de la cicatricule au moment qu'il sort du corps de la
poule." [Footnote: _Ibid_., p. 351.]

The "moule intérieur" of Buffon is the aggregate of elementary parts which
constitute the individual, and is thus the equivalent of Bonnet's germ,
[Footnote: See particularly Buffon, _l. c._ p. 41.] as defined in the
passage cited above. But Buffon further imagined that innumerable
"molecules organiques" are dispersed throughout the world, and that
alimentation consists in the appropriation by the parts of an organism of
those molecules which are analogous to them. Growth, therefore, was, on
this hypothesis, a process partly of simple evolution, and partly of what
has been termed "syngenesis." Buffon's opinion is, in fact, a sort of
combination of views, essentially similar to those of Bonnet, with others,
somewhat similar to those of the "Medici" whom Harvey condemns. The
"molecules organiques" are physical equivalents of Leibnitz's "monads."

It is a striking example of the difficulty of getting people to use their
own powers of investigation accurately, that this form of the doctrine of
evolution should have held its ground so long; for it was thoroughly and
completely exploded, not long after its enunciation, by Casper Friederich
Wolff, who in his "Theoria Generationis," published in 1759, placed the
opposite theory of epigenesis upon the secure foundation of fact, from
which it has never been displaced. But Wolff had no immediate successors.
The school of Cuvier was lamentably deficient in embryologists; and it was
only in the course of the first thirty years of the present century, that
Prévost and Dumas in France, and, later on, Döllinger, Pander, Von Bär,
Rathke, and Remak in Germany, founded modern embryology; while, at the same
time, they proved the utter incompatibility of the hypothesis of evolution,
as formulated by Bonnet and Haller, with easily demonstrable facts.

Nevertheless, though the conceptions originally denoted by "evolution" and
"development" were shown to be untenable, the words retained their
application to the process by which the embryos of living beings gradually
make their appearance; and the terms "Development," "Entwickelung," and
"Evolutio," are now indiscriminately used for the series of genetic changes
exhibited by living beings, by writers who would emphatically deny that
"Development" or "Entwickelung" or "Evolutio," in the sense in which these
words were usually employed by Bonnet or by Haller, ever occurs.

Evolution, or development, is, in fact, at present employed in biology as a
general name for the history of the steps by which any living being has
acquired the morphological and the physiological characters which
distinguish it. As civil history may be divided into biography, which is
the history of individuals, and universal history, which is the history of
the human race, so evolution falls naturally into two categories--the
evolution of the individual, and the evolution of the sum of living beings.
It will be convenient to deal with the modern doctrine of evolution under
these two heads.

I. _The Evolution of the Individual_.

No exception is at this time, known to the general law, established upon an
immense multitude of direct observations, that every living thing is
evolved from a particle of matter in which no trace of the distinctive
characters of the adult form of that living thing is discernible. This
particle is termed a _germ_. Harvey [Footnote: _Execitationes de
Generatione_. Ex. 62, "Ovum esse primordium commune omnibus
animalibus."] says--

"Omnibus viventibus primordium insit, ex quo et a quo proveniant. Liceat
hoc nobis _primordium vegetale_ nominare; nempe substantiam quandam
corpoream vitam habentem potentiâ; vel quoddam per se existens, quod aptum
sit, in vegetativam formam, ab interno principio operante, mutari. Quale
nempe primordium, ovum est et plantarum semen; tale etiam viviparorum
conceptus, et insectorum _vermis_ ab Aristotele dictus: diversa
scilicet diversorum viventium primordia."

The definition of a germ as "matter potentially alive, and having within
itself the tendency to assume a definite living form," appears to meet all
the requirements of modern science. For, notwithstanding it might be justly
questioned whether a germ is not merely potentially, but rather actually,
alive, though its vital manifestations are reduced to a minimum, the term
"potential" may fairly be used in a sense broad enough to escape the
objection. And the qualification of "potential" has the advantage of
reminding us that the great characteristic of the germ is not so much what
it is, but what it may, under suitable conditions, become. Harvey shared
the belief of Aristotle--whose writings he so often quotes and of whom he
speaks as his precursor and model, with the generous respect with which one
genuine worker should regard another--that such germs may arise by a
process of "equivocal generation" out of not-living matter; and the
aphorism so commonly ascribed to him, "_omne vivum ex ovo_" and which
is indeed a fair summary of his reiterated assertions, though incessantly
employed against the modern advocates of spontaneous generation, can be
honestly so used only by those who have never read a score of pages of the
"Exercitationes." Harvey, in fact, believed as implicitly as Aristotle did
in the equivocal generation of the lower animals. But, while the course of
modern investigation has only brought out into greater prominence the
accuracy of Harvey's conception of the nature and mode of development of
germs, it has as distinctly tended to disprove the occurrence of equivocal
generation, or abiogenesis, in the present course of nature. In the immense
majority of both plants and animals, it is certain that the germ is not
merely a body in which life is dormant or potential, but that it is itself
simply a detached portion of the substance of a pre-existing living body;
and the evidence has yet to be adduced which will satisfy any cautious
reasoner that "omne vivum ex vivo" is not as well-established a law of the
existing course of nature as "omne vivum ex ovo."

In all instances which have yet been investigated, the substance of this
germ has a peculiar chemical composition, consisting of at fewest four
elementary bodies, viz., carbon, hydrogen, oxygen, and nitrogen, united
into the ill-defined compound known as protein, and associated with much
water, and very generally, if not always, with sulphur and phosphorus in
minute proportions. Moreover, up to the present time, protein is known only
as a product and constituent of living matter. Again, a true germ is either
devoid of any structure discernible by optical means, or, at most, it is a
simple nucleated cell. [Footnote: In some cases of sexless multiplication
the germ is a cell-aggregate--if we call germ only that which is already
detached from the parent organism.]

In all cases the process of evolution consists in a succession of changes
of the form, structure, and functions of the germ, by which it passes, step
by step, from an extreme simplicity, or relative homogeneity, of visible
structure, to a greater or less degree of complexity or heterogeneity; and
the course of progressive differentiation is usually accompanied by growth,
which is effected by intussusception. This intussusception, however, is a
very different process from that imagined either by Buffon or by Bonnet.
The substance by the addition of which the germ is enlarged is in no case
simply absorbed, ready-made, from the not-living world and packed between
the elementary constituents of the germ, as Bonnet imagined; still less
does it consist of the "molecules organiques" of Buffon. The new material
is, in great measure, not only absorbed but assimilated, so that it becomes
part and parcel of the molecular structure of the living body into which it
enters. And, so far from the fully developed organism being simply the germ
_plus_ the nutriment which it has absorbed, it is probable that the
adult contains neither in form, nor in substance, more than an
inappreciable fraction of the constituents of the germ, and that it is
almost, if not wholly, made up of assimilated and metamorphosed nutriment.
In the great majority of cases, at any rate, the full-grown organism
becomes what it is by the absorption of not-living matter, and its
conversion into living matter of a specific type. As Harvey says (Ex. 45),
all parts of the body are nourished "ab eodem succo alibili, aliter
aliterque cambiato," "ut plantæ omnes ex eodem communi nutrimento (sive
rore seu terræ humore)."

In all animals and plants above the lowest the germ is a nucleated cell,
using that term in its broadest sense; and the first step in the process of
the evolution of the individual is the division of this cell into two or
more portions. The process of division is repeated, until the organism,
from being unicellular, becomes multicellular. The single cell becomes a
cell-aggregate; and it is to the growth and metamorphosis of the cells of
the cell-aggregate thus produced, that all the organs and tissues of the
adult owe their origin.

In certain animals belonging to every one of the chief groups into which
the _Metazoa_ are divisible, the cells of the cell-aggregate which
results from the process of yelk-division, and which is termed a
_morula_, diverge from one another in such a manner as to give rise to
a central space, around which they dispose themselves as a coat or
envelope; and thus the morula becomes a vesicle filled with fluid, the
_planula_. The wall of the planula is next pushed in on one side, or
invaginated, whereby it is converted into a double-walled sac with an
opening, the _blastopore_, which leads into the cavity lined by the
inner wall. This cavity is the primitive alimentary cavity or
_archenteron_; the inner or invaginated layer is the _hypoblast_;
the outer the _epiblast_; and the embryo, in this stage, is termed a
_gastrula_. In all the higher animals a layer of cells makes its
appearance between the hypoblast and the epiblast, and is termed the
_mesoblast_. In the further course of development the epiblast becomes
the ectoderm or epidermic layer of the body; the hypoblast becomes the
epithelium of the middle portion of the alimentary canal; and the mesoblast
gives rise to all the other tissues, except the central nervous system,
which originates from an ingrowth of the epiblast.

With more or less modification in detail, the embryo has been observed to
pass through these successive evolutional stages in sundry Sponges,
Coelenterates, Worms, Echinoderms, Tunicates, Arthropods, Mollusks, and
Vertebrates; and there are valid reasons for the belief that all animals of
higher organisation than the _Protozoa_, agree in the general
character of the early stages of their individual evolution. Each, starting
from the condition of a simple nucleated cell, becomes a cell-aggregate;
and this passes through a condition which represents the gastrula stage,
before taking on the features distinctive of the group to which it belongs.
Stated in this form, the "gastræa theory" of Haeckel appears to the present
writer to be one of most important and best founded of recent
generalisations. So far as individual plants and animals are concerned,
therefore, evolution is not a speculation but a fact; and it takes place by

"Animal...per _epigenesin_ procreatur, materiam simul attrahit, parat,
concoquit, et eâdem utitur; formatur simul et augetur ... primum futuri
corporis concrementum ... prout augetur, dividitur sensim et distinguitur
in partes, non simul omnes, sed alias post alias natas, et ordine quasque
suo emergentes." [Footnote: Harvey, _Exercitationes de Generatione_.
Ex. 45, "Quænam sit pulli materia et quomodo fiat in Ovo."] In these words,
by the divination of genius, Harvey, in the seventeenth century, summed up
the outcome of the work of all those who, with appliances he could not
dream of, are continuing his labours in the nineteenth century.

Nevertheless, though the doctrine of epigenesis, as understood by Harvey,
has definitively triumphed over the doctrine of evolution, as understood by
his opponents of the eighteenth century, it is not impossible that, when
the analysis of the process of development is carried still further, and
the origin of the molecular components of the physically gross, though
sensibly minute, bodies which we term germs is traced, the theory of
development will approach more nearly to metamorphosis than to epigenesis.
Harvey thought that impregnation influenced the female organism as a
contagion; and that the blood, which he conceived to be the first rudiment
of the germ, arose in the clear fluid of the "colliquamentum" of the ovum
by a process of concrescence, as a sort of living precipitate. We now know,
on the contrary, that the female germ or ovum, in all the higher animals
and plants, is a body which possesses the structure of a nucleated cell;
that impregnation consists in the fusion of the substance [Footnote: [At
any rate of the nuclei of the two germ-cells. 1893]] of another more or
less modified nucleated cell, the male germ, with the ovum; and that the
structural components of the body of the embryo are all derived, by a
process of division, from the coalesced male and female germs. Hence it is
conceivable, and indeed probable, that every part of the adult contains
molecules, derived both from the male and from the female parent; and that,
regarded as a mass of molecules, the entire organism may he compared to a
web of which the warp is derived from the female and the woof from the
male. And each of these may constitute one individuality, in the same sense
as the whole organism is one individual, although the matter of the
organism has been constantly changing. The primitive male and female
molecules may play the part of Buffon's "moules organiques," and mould the
assimilated nutriment, each according to its own type, into innumerable new
molecules. From this point of view the process, which, in its superficial
aspect, is epigenesis, appears in essence, to be evolution, in the modified
sense adopted in Bonnet's later writings; and development is merely the
expansion of a potential organism or "original preformation" according to
fixed laws.

II. _The Evolution of the Sum of Living Beings_.

The notion that all the kinds of animals and plants may have come into
existence by the growth and modification of primordial germs is as old as
speculative thought; but the modern scientific form of the doctrine can be
traced historically to the influence of several converging lines of
philosophical speculation and of physical observation, none of which go
farther back than the seventeenth century. These are:--

1. The enunciation by Descartes of the conception that the physical
universe, whether living or not living, is a mechanism, and that, as such,
it is explicable on physical principles.

2. The observation of the gradations of structure, from extreme simplicity
to very great complexity, presented by living things, and of the relation
of these graduated forms to one another.

3. The observation of the existence of an analogy between the series of
gradations presented by the species which compose any great group of
animals or plants, and the series of embryonic conditions of the highest
members of that group.

4. The observation that large groups of species of widely different habits
present the same fundamental plan of structure; and that parts of the same
animal or plant, the functions of which are very different, likewise
exhibit modifications of a common plan.

5. The observation of the existence of structures, in a rudimentary and
apparently useless condition, in one species of a group, which are fully
developed and have definite functions in other species of the same group.

6. The observation of the effects of varying conditions in modifying living

7. The observation of the facts of geographical distribution.

8. The observation of the facts of the geological succession of the forms
of life.

1. Notwithstanding the elaborate disguise which fear of the powers that
were led Descartes to throw over his real opinions, it is impossible to
read the "Principes de la Philosophie" without acquiring the conviction
that this great philosopher held that the physical world and all things in
it, whether living or not living, have originated by a process of
evolution, due to the continuous operation of purely physical causes, out
of a primitive relatively formless matter. [Footnote: As Buffon has well
said:--"L'idée de ramener l'explication de tous les phénomènes à des
principes mecaniques est assurement grande et belle, ce pas est le plus
hardi qu'on peut faire en philosophie, et c'est Descartes qui l'a
fait."--_l. c._ p. 50.]

The following passage is especially instructive:--

"Et tant s'en faut que je veuille que l'on croie toutes les choses que
j'écrirai, que même je pretends en proposer ici quelques unes que je crois
absolument être fausses; à savoir, je ne doute point quo le monde n'ait été
créé au commencement avec autant de perfection qu'il eu a; en sorte que le
soleil, la terre, la lune, et les étoiles ont été dès lors; et que la terre
n'a pas eu seulement en soi les semences des plantes, mais que les plantes
même en ont couvert une partie; et qu' Adam et Eve n'ont pas été créés
enfans mais en âge d'hommes parfaits. La religion chrétienne veut que nous
le croyons ainsi, et la raison naturelle nous persuade entièrement cette
vérité; car si nous considérons la toute puissance de Dieu, nous devons
juger que tout ce qu'il a fait a eu dès le commencement toute la perfection
qu'il devoit avoir. Mais néanmoins, comme on connôitroit beaucoup mieux
quelle a été la nature d'Adam et celle des arbres de Paradis si on avoit
examiné comment les enfants se forment peu à peu dans le ventre de leurs
mères et comment les plantes sortent de leurs semences, que si on avoit
seulement considéré quels ils ont été quand Dieu les a créés: tout de même,
nous ferons mieux entendre quelle est généralement la nature de toutes les
choses qui sont au monde si nous pouvons imaginer quelques principes qui
soient fort intelligibles et fort simples, desquels nous puissions voir
clairement que les astres et la terre et enfin tout ce monde visible auroit
pu être produit ainsi que de quelques semences (bien que, nous sachions
qu'il n'a pas été produit en cette façon) que si nous la decrivions
seulement comme il est, ou bien comme nous croyons qu'il a été créé. Et
parceque je pense avoir trouvé des principes qui sont tels, je tacherai ici
de les expliquer." [Footnote: _Principes de la Philosophie_, Troisième
partie, § 45.]

If we read between the lines of this singular exhibition of force of one
kind and weakness of another, it is clear that Descartes believed that he
had divined the mode in which the physical universe had been evolved; and
the "Traité de l'Homme," and the essay "Sur les Passions" afford abundant
additional evidence that he sought for, and thought he had found, an
explanation of the phenomena of physical life by deduction from purely
physical laws.

Spinoza abounds in the same sense, and is as usual perfectly candid--

"Naturæ leges et regulæ, secundum quas omnia fiunt et ex unis formis in
alias mutantur, sunt ubique et semper eadem." [Footnote: _Ethices_,
Pars tertia, Præfatio.] Leibnitz's doctrine of continuity necessarily led
him in the same direction; and, of the infinite multitude of monads with
which he peopled the world, each is supposed to be the focus of an endless
process of evolution and involution. In the "Protogæa," xxvi., Leibnitz
distinctly suggests the mutability of species--

"Alii mirantur in saxis passim species videri quas vel in orbe cognito, vel
saltem in vicinis locis frustra quæras. 'Ita Cornua Ammonis,' quæ ex
nautilorum numero habeantur, passim et forma et magnitudine (nam et pedali
diametro aliquando reperiuntur) ab omnibus illis naturis discrepare dicunt,
quas præbet mare. Sed quis absconditos ejus recessus aut subterraneas
abyssos pervestigavit? quam multa nobis animalia antea ignota offert novus
orbis? Et credibile est per magnas illas conversiones etiam animalium
species plurimum immutatas."

Thus, in the end of the seventeenth century, the seed was sown which has,
at intervals, brought forth recurrent crops of evolutional hypotheses,
based, more or less completely, on general reasonings.

Among the earliest of these speculations is that put forward by Benoit de
Maillet in his "Telliamed," which, though printed in 1735, was not
published until twenty-three years later. Considering that this book was
written before the time of Haller, or Bonnet, or Linnæus, or Hutton, it
surely deserves more respectful consideration than it usually receives. For
De Maillet not only has a definite conception of the plasticity of living
things, and of the production of existing species by the modification of
their predecessors; but he clearly apprehends the cardinal maxim of modern
geological science, that the explanation of the structure of the globe is
to be sought in the deductive application to geological phenomena of the
principles established inductively by the study of the present course of
nature. Somewhat later, Maupertuis [Footnote: _Système de la Nature_.
"Essai sur la Formation des Corps Organisés," 1751, xiv.] suggested a
curious hypothesis as to the causes of variation, which he thinks may be
sufficient to account for the origin of all animals from a single pair.
Robinet [Footnote: _Considérations Philosophiques sur la gradation
naturelle des formes de l'être; ou les essais de la nature qui apprend a
faire l'homme,_ 1768.] followed out much the same line of thought as De
Maillet, but less soberly; and Bonnet's speculations in the "Palingénésie,"
which appeared in 1769, have already been mentioned. Buffon (1753-1778), at
first a partisan of the absolute immutability of species, subsequently
appears to have believed that larger or smaller groups of species have been
produced by the modification of a primitive stock; but he contributed
nothing to the general doctrine of evolution.

Erasmus Darwin ("Zoonomia," 1794), though a zealous evolutionist, can
hardly be said to have made any real advance on his predecessors; and,
notwithstanding that Goethe (1791-4) had the advantage of a wide knowledge
of morphological facts, and a true insight into their signification, while
he threw all the power of a great poet into the expression of his
conceptions, it may be questioned whether he supplied the doctrine of
evolution with a firmer scientific basis than it already possessed.
Moreover, whatever the value of Goethe's labours in that field, they were
not published before 1820, long after evolutionism had taken a new
departure from the works of Treviranus and Lamarck--the first of its
advocates who were equipped for their task with the needful large and
accurate knowledge of the phenomena of life, as a whole. It is remarkable
that each of these writers seems to have been led, independently and
contemporaneously, to invent the same name of "Biology" for the science of
the phenomena of life; and thus, following Buffon, to have recognised the
essential unity of these phenomena, and their contradistinction from those
of inanimate nature. And it is hard to say whether Lamarck or Treviranus
has the priority in propounding the main thesis of the doctrine of
evolution; for though the first volume of Treviranus's "Biologie" appeared
only in 1802, he says, in the preface to his later work, the "Erscheinungen
und Gesetze des organischen Lebens," dated 1831, that he wrote the first
volume of the "Biologie" "nearly five-and-thirty years ago," or about 1796.

Now, in 1794, there is evidence that Lamarck held doctrines which present a
striking contrast to those which are to be found in the "Philosophie
Zoologique," as the following passages show:--

"685. Quoique mon unique objet dans cet article n'ait été que de traiter de
la cause physique de l'entretien de la vie des êtres organiques, malgré
cela j'ai osé avancer en débutant, que l'existence de ces êtres étonnants
n'appartiennent nullement à la nature; que tout ce qu'on peut entendre par
le mot _nature_, ne pouvoit donner la vie, c'est-à-dire, que toutes
les qualités de la matière, jointes à toutes les circonstances possibles,
et même à l'activité répandue dans l'univers, ne pouvaient point produire
un être muni du mouvement organique, capable de reproduire son semblable,
et sujet à la mort.

"686. Tous les individus de cette nature, qui existent, proviennent
d'individus semblables qui tous ensemble constituent l'espèce entière. Or,
je crois qu'il est aussi impossible à l'homme de connôitre la cause
physique du premier individu de chaque espèce, que d'assigner aussi
physiquement la cause de l'existence de la matière ou de l'univers entier.
C'est au moins ce que le résultat de mes connaissances et de mes réflexions
me portent à penser. S'il existe beaucoup de variétés produites par l'effet
des circonstances, ces variétés ne denaturent point les espèces; mais on se
trompe, sans doute souvent, en indiquant comme espèce, ce qui n'est que
variété; et alors je sens que cette erreur peut tirer à conséquence dans
les raisonnements que l'on fait sur cette matière." [Footnote:
_Recherches sur les causes des principaux faits physiques_, par J.B.
Lamarck. Paris. Seconde année de la République. In the preface, Lamarck
says that the work was written in 1776, and presented to the Academy in
1780; but it was not published before 17994, and, at that time, it
presumably expressed Lamarck's mature views. It would be interesting to
know what brought about the change of opinion manifested in the
_Recherches sur l'organisation des corps vivants_, published only
seven years later.]

The first three volumes of Treviranus's "Biologie," which contain his
general views of evolution, appeared between 1802 and 1805. The "Recherches
sur l'organisation des corps vivants," in which the outlines of Lamarck's
doctrines are given, was published in 1802, but the full development of his
views, in the "Philosophie Zoologique," did not take place until 1809.

The "Biologie" and the "Philosophie Zoologique" are both very remarkable
productions, and are still worthy of attentive study, but they fell upon
evil times. The vast authority of Cuvier was employed in support of the
traditionally respectable hypotheses of special creation and of
catastrophism; and the wild speculations of the "Discours sur les
Révolutions de la Surface du Globe" were held to be models of sound
scientific thinking, while the really much more sober and philosophical
hypotheses of the "Hydrogeologie" were scouted. For many years it was the
fashion to speak of Lamarck with ridicule, while Treviranus was altogether

Nevertheless, the work had been done. The conception of evolution was
henceforward irrepressible, and it incessantly reappears, in one shape or
another, [Footnote: See the "Historical Sketch" prefixed to the last
edition of the _Origin of Species_.] up to the year 1858, when Mr.
Darwin and Mr. Wallace published their "Theory of Natural Selection." The
"Origin of Species" appeared in 1859; and it is within the knowledge of all
whose memories go back to that time, that, henceforward, the doctrine of
evolution has assumed a position and acquired an importance which it never
before possessed. In the "Origin of Species," and in his other numerous and
important contributions to the solution of the problem of biological
evolution, Mr. Darwin confines himself to the discussion of the causes
which have brought about the present condition of living matter, assuming
such matter to have once come into existence. On the other hand, Mr.
Spencer [Footnote: _First Principles_. and _Principles of
Biology_, 1860-1864.] and Professor Haeckel [Footnote: _Generelle
Marphologie_, 1866.] have dealt with the whole problem of evolution. The
profound and vigorous writings of Mr. Spencer embody the spirit of
Descartes in the knowledge of our own day, and may be regarded as the
"Principes de la Philosophie" of the nineteenth century; while, whatever
hesitation may not unfrequently be felt by less daring minds, in following
Haeckel in many of his speculations, his attempt to systematise the
doctrine of evolution and to exhibit its influence as the central thought
of modern biology, cannot fail to have a far-reaching influence on the
progress of science.

If we seek for the reason of the difference between the scientific position
of the doctrine of evolution a century ago, and that which it occupies now,
we shall find it in the great accumulation of facts, the several classes of
which have been enumerated above, under the second to the eighth heads. For
those which are grouped under the second to the seventh of these classes,
respectively, have a clear significance on the hypothesis of evolution,
while they are unintelligible if that hypothesis be denied. And those of
the eighth group are not only unintelligible without the assumption of
evolution, but can be proved never to be discordant with that hypothesis,
while, in some cases, they are exactly such as the hypothesis requires. The
demonstration of these assertions would require a volume, but the general
nature of the evidence on which they rest may be briefly indicated.

2. The accurate investigation of the lowest forms of animal life, commenced
by Leeuwenhoek and Swammerdam, and continued by the remarkable labours of
Reaumur, Trembley, Bonnet, and a host of other observers, in the latter
part of the seventeenth and the first half of the eighteenth centuries,
drew the attention of biologists to the gradation in the complexity of
organisation which is presented by living beings, and culminated in the
doctrine of the "échelle des êtres," so powerfully and clearly stated by
Bonnet; and, before him, adumbrated by Locke and by Leibnitz. In the then
state of knowledge, it appeared that all the species of animals and plants
could be arranged in one series; in such a manner that, by insensible
gradations, the mineral passed into the plant, the plant into the polype,
the polype into the worm, and so, through gradually higher forms of life,
to man, at the summit of the animated world.

But, as knowledge advanced, this conception ceased to be tenable in the
crude form in which it was first put forward. Taking into account existing
animals and plants alone, it became obvious that they fell into groups
which were more or less sharply separated from one another; and, moreover,
that even the species of a genus can hardly ever be arranged in linear
series. Their natural resemblances and differences are only to be expressed
by disposing them as if they were branches springing from a common
hypothetical centre.

Lamarck, while affirming the verbal proposition that animals form a single
series, was forced by his vast acquaintance with the details of zoology to
limit the assertion to such a series as may be formed out of the
abstractions constituted by the common characters of each group. [Footnote:
"Il s'agit donc de prouver que la série qui constitue l'échelle animale
réside essentiellement dans la distribution des masses principales qui la
composent et non dans celle des espèces ni même toujours dans celle des
genres."--_Philosophie Zoologique_. chap. v.]

Cuvier on anatomical, and Von Baer on embryological grounds, made the
further step of proving that, even in this limited sense, animals cannot be
arranged in a single series, but that there are several distinct plans of
organisation to be observed among them, no one of which, in its highest and
most complicated modification, leads to any of the others.

The conclusions enunciated by Cuvier and Von Baer have been confirmed, in
principle, by all subsequent research into the structure of animals and
plants. But the effect of the adoption of these conclusions has been rather
to substitute a new metaphor for that of Bonnet than to abolish the
conception expressed by it. Instead of regarding living things as capable
of arrangement in one series like the steps of a ladder, the results of
modern investigation compel us to dispose them as if they were the twigs
and branches of a tree. The ends of the twigs represent individuals, the
smallest groups of twigs species, larger groups genera, and so on, until we
arrive at the source of all these ramifications of the main branch, which
is represented by a common plan of structure. At the present moment, it is
impossible to draw up any definition, based on broad anatomical or
developmental characters, by which any one of Cuvier's great groups shall
be separated from all the rest. On the contrary, the lower members of each
tend to converge towards the lower members of all the others. The same may
be said of the vegetable world. The apparently clear distinction between
flowering and flowerless plants has been broken down by the series of
gradations between the two exhibited by the _Lycopodiaceæ,
Rhizocarpeæ_, and _Gymnospermeæ_. The groups of _Fungi_,
_Lichenes_, and _Algæ_ have completely run into one another, and,
when the lowest forms of each are alone considered, even the animal and
vegetable kingdoms cease to have a definite frontier.

If it is permissible to speak of the relations of living forms to one
another metaphorically, the similitude chosen must undoubtedly be that of a
common root, whence two main trunks, one representing the vegetable and one
the animal world, spring; and, each dividing into a few main branches,
these subdivide into multitudes of branchlets and these into smaller groups
of twigs.

As Lamarck has well said--[Footnote: _Philosophie Zoologique_,
première partie, chap. iii.] "Il n'y a que ceux qui se sont longtemps et
fortement occupés de la détermination des espèces, et qui ont consulté de
riches collections, qui peuvent savoir jusqu'à quel point les
_espèces_, parmi les corps vivants se fondent les unes dans les
autres, et qui ont pu se convaincre que, dans les parties où nous voyons
des _espèces_ isolès, cela n'est ainsi que parcequ'il nous en manque
d'autres qui en sont plus voisines et que nous n'avons pas encore

"Je ne veux pas dire pour cela que les animaux qui existent forment une
série très-simple et partout également nuancée; mais je dis qu'ils forment
une série ramense, irréguliérement graduée et qui n'a point de
discontinuité dans ses parties, ou qui, du moins, n'en a toujours pas eu,
s'il est vrai que, par suite de quelques espèces perdues, il s'en trouve
quelque part. Il en resulte que les _espèces_ qui terminent chaque
rameau de la série générale tiennent, au moins d'un côté, à d'autres
espèces voisines qui se nuancent avec elles. Voilà ce que l'état bien connu
des choses me met maintenant à portée de demontrer. Je n'ai besoin d'aucune
hypothèse ni d'aucune supposition pour cela: j'en atteste tous les
naturalistes observateurs."

3. In a remarkable essay [Footnote: "Entwurf einer Darstellung der zwischen
dem Embryozustände der höheren Thiere und dem permanenten der niederen
stattfindenden Parallele," _Beyträge zur Vergleichenden Anatomie_, Bd.
ii. 1811.] Meckel remarks--

"There is no good physiologist who has not been struck by the observation
that the original form of all organisms is one and the same, and that out
of this one form, all, the lowest as well as the highest, are developed in
such a manner that the latter pass through the permanent forms of the
former as transitory stages. Aristotle, Haller, Harvey, Kielmeyer,
Autenrieth, and many others, have either made this observation
incidentally, or, especially the latter, have drawn particular attention to
it, and deduced therefrom results of permanent importance for physiology."

Meckel proceeds to exemplify the thesis, that the lower forms of animals
represent stages in the course of the development of the higher, with a
large series of illustrations.

After comparing the Salamanders and the perennibranchiate _Urodela_
with the Tadpoles and the Frogs, and enunciating the law that the more
highly any animal is organised the more quickly does it pass through the
lower stages, Meckel goes on to say--

"From these lowest Vertebrata to the highest, and to the highest forms
among these, the comparison between the embryonic conditions of the higher
animals and the adult states of the lower can be more completely and
thoroughly instituted than if the survey is extended to the Invertebrata,
inasmuch as the latter are in many respects constructed upon an altogether
too dissimilar type; indeed they often differ from one another far more
than the lowest vertebrate does from the highest mammal; yet the following
pages will show that the comparison may also be extended to them with
interest. In fact, there is a period when, as Aristotle long ago said, the
embryo of the highest animal has the form of a mere worm; and, devoid of
internal and external organisation, is merely an almost structureless lump
of polype substance. Notwithstanding the origin of organs, it still for a
certain time, by reason of its want of an internal bony skeleton, remains
worm and mollusk, and only later enters into the series of the Vertebrata,
although traces of the vertebral column even in the earliest periods
testify its claim to a place in that series."--_Op, cit_ pp. 4, 5.

If Meckel's proposition is so far qualified, that the comparison of adult
with embryonic forms is restricted within the limits of one type of
organisation; and, if it is further recollected that the resemblance
between the permanent lower form and the embryonic stage of a higher form
is not special but general, it is in entire accordance with modern
embryology; although there is no branch of biology which has grown so
largely, and improved its methods so much, since Meckel's time, as this. In
its original form, the doctrine of "arrest of development," as advocated by
Geoffroy Saint-Hilaire and Serres, was no doubt an overstatement of the
case. It is not true, for example, that a fish is a reptile arrested in its
development, or that a reptile was ever a fish: but it is true that the
reptile embryo, at one stage of its development, is an organism which, if
it had an independent existence, must be classified among fishes; and all
the organs of the reptile pass, in the course of their development, through
conditions which are closely analogous to those which are permanent in some

4. That branch of biology which is termed Morphology is a commentary upon,
and expansion of, the proposition that widely different animals or plants,
and widely different parts of animals or plants, are constructed upon the
same plan. From the rough comparison of the skeleton of a bird with that of
a man by Belon, in the sixteenth century (to go no farther back), down to
the theory of the limbs and the theory of the skull at the present day; or,
from the first demonstration of the homologies of the parts of a flower by
C. F. Wolff, to the present elaborate analysis of the floral organs,
morphology exhibits a continual advance towards the demonstration of a
fundamental unity among the seeming diversities of living structures. And
this demonstration has been completed by the final establishment of the
cell theory, which involves the admission of a primitive conformity, not
only of all the elementary structures in animals and plants respectively,
but of those in the one of these great divisions of living things with
those in the other. No _à priori_ difficulty can be said to stand in
the way of evolution, when it can be shown that all animals and all plants
proceed by modes of development, which are similar in principle, from a
fundamental protoplasmic material.

5. The innumerable cases of structures, which are rudimentary and
apparently useless, in species, the close allies of which possess
well-developed and functionally important homologous structures, are
readily intelligible on the theory of evolution, while it is hard to
conceive their _raison d'être_ on any other hypothesis. However, a
cautious reasoner will probably rather explain such cases deductively from
the doctrine of evolution than endeavour to support the doctrine of
evolution by them. For it is almost impossible to prove that any structure,
however rudimentary, is useless--that is to say, that it plays no part
whatever in the economy; and, if it is in the slightest degree useful,
there is no reason why, on the hypothesis of direct creation, it should not
have been created. Nevertheless, double-edged as is the argument from
rudimentary organs, there is probably none which has produced a greater
effect in promoting the general acceptance of the theory of evolution.

6. The older advocates of evolution sought for the causes of the process
exclusively in the influence of varying conditions, such as climate and
station, or hybridisation, upon living forms. Even Treviranus has got no
farther than this point. Lamarck introduced the conception of the action of
an animal on itself as a factor in producing modification. Starting from
the well-known fact that the habitual use of a limb tends to develop the
muscles of the limb, and to produce a greater and greater facility in using
it, he made the general assumption that the effort of an animal to exert an
organ in a given direction tends to develop the organ in that direction.
But a little consideration showed that, though Lamarck had seized what, as
far it goes, is a true cause of modification, it is a cause the actual
effects of which are wholly inadequate to account for any considerable
modification in animals, and which can have no influence at all in the
vegetable world; and probably nothing contributed so much to discredit
evolution, in the early part of this century, as the floods of easy
ridicule which were poured upon this part of Lamarck's speculation. The
theory of natural selection, or survival of the fittest, was suggested by
Wells in 1813, and further elaborated by Matthew in 1831. But the pregnant
suggestions of these writers remained practically unnoticed and forgotten,
until the theory was independently devised and promulgated by Darwin and
Wallace in 1858, and the effect of its publication was immediate and

Those who were unwilling to accept evolution, without better grounds than
such as are offered by Lamarck, or the author of that particularly
unsatisfactory book, the "Vestiges of the Natural History of the Creation,"
and who therefore preferred to suspend their judgment on the question,
found in the principle of selective breeding, pursued in all its
applications with marvellous knowledge and skill by Mr. Darwin, a valid
explanation of the occurrence of varieties and races; and they saw clearly
that, if the explanation would apply to species, it would not only solve
the problem of their evolution, but that it would account for the facts of
teleology, as well as for those of morphology; and for the persistence of
some forms of life unchanged through long epochs of time, while others
undergo comparatively rapid metamorphosis.

How far "natural selection" suffices for the production of species remains
to be seen. Few can doubt that, if not the whole cause, it is a very
important factor in that operation; and that it must play a great part in
the sorting out of varieties into those which are transitory and those
which are permanent.

But the causes and conditions of variation have yet to be thoroughly
explored; and the importance of natural selection will not be impaired,
even if further inquiries should prove that variability is definite, and is
determined in certain directions rather than in others, by conditions
inherent in that which varies. It is quite conceivable that every species
tends to produce varieties of a limited number and kind, and that the
effect of natural selection is to favour the development of some of these,
while it opposes the development of others along their predetermined lines
of modification.

7. No truths brought to light by biological investigation were better
calculated to inspire distrust of the dogmas intruded upon science in the
name of theology, than those which relate to the distribution of animals
and plants on the surface of the earth. Very skilful accommodation was
needful, if the limitation of sloths to South America, and of the
ornithorhynchus to Australia, was to be reconciled with the literal
interpretation of the history of the deluge; and with the establishment of
the existence of distinct provinces of distribution, any serious belief in
the peopling of the world by migration from Mount Ararat came to an end.

Under these circumstances, only one alternative was left for those who
denied the occurrence of evolution--namely, the supposition that the
characteristic animals and plants of each great province were created as
such, within the limits in which we find them. And as the hypothesis of
"specific centres," thus formulated, was heterodox from the theological
point of view, and unintelligible under its scientific aspect, it may be
passed over without further notice, as a phase of transition from the
creational to the evolutional hypothesis.

8. In fact, the strongest and most conclusive arguments in favour of
evolution are those which are based upon the facts of geographical, taken
in conjunction with those of geological, distribution.

Both Mr. Darwin and Mr. Wallace lay great stress on the close relation
which obtains between the existing fauna of any region and that of the
immediately antecedent geological epoch in the same region; and rightly,
for it is in truth inconceivable that there should be no genetic connection
between the two. It is possible to put into words the proposition that all
the animals and plants of each geological epoch were annihilated and that a
new set of very similar forms was created for the next epoch; but it may be
doubted if any one who ever tried to form a distinct mental image of this
process of spontaneous generation on the grandest scale, ever really
succeeded in realising it.

Within the last twenty years, the attention of the best palæontologists has
been withdrawn from the hodman's work of making "new species" of fossils,
to the scientific task of completing our knowledge of individual species,
and tracing out the succession of the forms presented by any given type in

Those who desire to inform themselves of the nature and extent of the
evidence bearing on these questions may consult the works of Rütimeyer,
Gaudry, Kowalewsky, Marsh, and the writer of the present article. It must
suffice, in this place, to say that the successive forms of the Equine type
have been fully worked out; while those of nearly all the other existing
types of Ungulate mammals and of the _Carnivora_ have been almost as
closely followed through the Tertiary deposits; the gradations between
birds and reptiles have been traced; and the modifications undergone by the
_Crocodilia_, from the Triassic epoch to the present day, have been
demonstrated. On the evidence of palæontology, the evolution of many
existing forms of animal life from their predecessors is no longer an
hypothesis, but an historical fact; it is only the nature of the
physiological factors to which that evolution is due which is still open to

[At page 209, the reference to Erasmus Darwin does not do justice to that
ingenious writer, who, in the 39th section of the _Zoonomia_, clearly
and repeatedly enunciates the theory of the inheritance of acquired
modifications. For example "From their first rudiment, or primordium, to
the termination of their lives, all animals undergo perpetual
transformations; which are in part produced by their own exertions in
consequence of their desires and aversions, of their pleasures and their
pains, or of irritation, or of associations; and many of these acquired
forms or propensities are transmitted to their posterity." _Zoonomia_
I., p. 506. 1893.]




Many of you will be familiar with the aspect of this small green-covered
book. It is a copy of the first edition of the "Origin of Species," and
bears the date of its production--the 1st of October 1859. Only a few
months, therefore, are needed to complete the full tale of twenty-one years
since its birthday.

Those whose memories carry them back to this time will remember that the
infant was remarkably lively, and that a great number of excellent persons
mistook its manifestations of a vigorous individuality for mere
naughtiness; in fact there was a very pretty turmoil about its cradle. My
recollections of the period are particularly vivid, for, having conceived a
tender affection for a child of what appeared to me to be such remarkable
promise, I acted for some time in the capacity of a sort of under-nurse,
and thus came in for my share of the storms which threatened the very life
of the young creature. For some years it was undoubtedly warm work; but
considering how exceedingly unpleasant the apparition of the newcomer must
have been to those who did not fall in love with him at first sight, I
think it is to the credit of our age that the war was not fiercer, and that
the more bitter and unscrupulous forms of opposition died away as soon as
they did.

I speak of this period as of something past and gone, possessing merely an
historical, I had almost said an antiquarian interest. For, during the
second decade of the existence of the "Origin of Species," opposition,
though by no means dead, assumed a different aspect. On the part of all
those who had any reason to respect themselves, it assumed a thoroughly
respectful character. By this time, the dullest began to perceive that the
child was not likely to perish of any congenital weakness or infantile
disorder, but was growing into a stalwart personage, upon whom mere goody
scoldings and threatenings with the birch-rod were quite thrown away.

In fact, those who have watched the progress of science within the last ten
years will bear me out to the full, when I assert that there is no field of
biological inquiry in which the influence of the "Origin of Species" is not
traceable; the foremost men of science in every country are either avowed
champions of its leading doctrines, or at any rate abstain from opposing
them; a host of young and ardent investigators seek for and find
inspiration and guidance in Mr. Darwin's great work; and the general
doctrine of evolution, to one side of which it gives expression, obtains,
in the phenomena of biology, a firm base of operations whence it may
conduct its conquest of the whole realm of Nature.

History warns us, however, that it is the customary fate of new truths to
begin as heresies and to end as superstitions; and, as matters now stand,
it is hardly rash to anticipate that, in another twenty years, the new
generation, educated under the influences of the present day, will be in
danger of accepting the main doctrines of the "Origin of Species," with as
little reflection, and it may be with as little justification, as so many
of our contemporaries, twenty years ago, rejected them.

Against any such a consummation let us all devoutly pray; for the
scientific spirit is of more value than its products, and irrationally held
truths may be more harmful than reasoned errors. Now the essence of the
scientific spirit is criticism. It tells us that whenever a doctrine claims
our assent we should reply, Take it if you can compel it. The struggle for
existence holds as much in the intellectual as in the physical world. A
theory is a species of thinking, and its right to exist is coextensive with
its power of resisting extinction by its rivals.

From this point of view, it appears to me that it would be but a poor way
of celebrating the Coming of Age of the "Origin of Species," were I merely
to dwell upon the facts, undoubted and remarkable as they are, of its
far-reaching influence and of the great following of ardent disciples who
are occupied in spreading and developing its doctrines. Mere insanities and
inanities have before now swollen to portentous size in the course of
twenty years. Let us rather ask this prodigious change in opinion to
justify itself: let us inquire whether anything has happened since 1859,
which will explain, on rational grounds, why so many are worshipping that
which they burned, and burning that which they worshipped. It is only in
this way that we shall acquire the means of judging whether the movement we
have witnessed is a mere eddy of fashion, or truly one with the
irreversible current of intellectual progress, and, like it, safe from
retrogressive reaction.

Every belief is the product of two factors: the first is the state of the
mind to which the evidence in favour of that belief is presented; and the
second is the logical cogency of the evidence itself. In both these
respects, the history of biological science during the last twenty years
appears to me to afford an ample explanation of the change which has taken
place; and a brief consideration of the salient events of that history will
enable us to understand why, if the "Origin of Species" appeared now, it
would meet with a very different reception from that which greeted it in

One-and-twenty years ago, in spite of the work commenced by Hutton and
continued with rare skill and patience by Lyell, the dominant view of the
past history of the earth was catastrophic. Great and sudden physical
revolutions, wholesale creations and extinctions of living beings, were the
ordinary machinery of the geological epic brought into fashion by the
misapplied genius of Cuvier. It was gravely maintained and taught that the
end of every geological epoch was signalised by a cataclysm, by which every
living being on the globe was swept away, to be replaced by a brand-new
creation when the world returned to quiescence. A scheme of nature which
appeared to be modelled on the likeness of a succession of rubbers of
whist, at the end of each of which the players upset the table and called
for a new pack, did not seem to shock anybody.

I may be wrong, but I doubt if, at the present time, there is a single
responsible representative of these opinions left. The progress of
scientific geology has elevated the fundamental principle of
uniformitarianism, that the explanation of the past is to be sought in the
study of the present, into the position of an axiom; and the wild
speculations of the catastrophists, to which we all listened with respect a
quarter of a century ago, would hardly find a single patient hearer at the
present day. No physical geologist now dreams of seeking, outside the range
of known natural causes, for the explanation of anything that happened
millions of years ago, any more than he would be guilty of the like
absurdity in regard to current events.

The effect of this change of opinion upon biological speculation is
obvious. For, if there have been no periodical general physical
catastrophes, what brought about the assumed general extinctions and
re-creations of life which are the corresponding biological catastrophes?
And, if no such interruptions of the ordinary course of nature have taken
place in the organic, any more than in the inorganic, world, what
alternative is there to the admission of evolution?

The doctrine of evolution in biology is the necessary result of the logical
application of the principles of uniformitarianism to the phenomena of
life. Darwin is the natural successor of Hutton and Lyell, and the "Origin
of Species" the logical sequence of the "Principles of Geology."

The fundamental doctrine of the "Origin of Species," as of all forms of the
theory of evolution applied to biology, is "that the innumerable species,
genera, and families of organic beings with which the world is peopled have
all descended, each within its own class or group, from common parents, and
have all been modified in the course of descent." [Footnote: _Origin of
Species_, ed. I, p. 457.]

And, in view of the facts of geology, it follows that all living animals
and plants "are the lineal descendants of those which lived long before the
Silurian epoch." [Footnote: _Origin of Species_, p. 458.]

It is an obvious consequence of this theory of descent with modification,
as it is sometimes called, that all plants and animals, however different
they may now be, must, at one time or other, have been connected by direct
or indirect intermediate gradations, and that the appearance of isolation
presented by various groups of organic beings must be unreal.

No part of Mr. Darwin's work ran more directly counter to the
prepossessions of naturalists twenty years ago than this. And such
prepossessions were very excusable, for there was undoubtedly a great deal
to be said, at that time, in favour of the fixity of species and of the
existence of great breaks, which there was no obvious or probable means of
filling up, between various groups of organic beings.

For various reasons, scientific and unscientific, much had been made of the
hiatus between man and the rest of the higher mammalia, and it is no wonder
that issue was first joined on this part of the controversy. I have no wish
to revive past and happily forgotten controversies; but I must state the
simple fact that the distinctions in the cerebral and other characters,
which were so hotly affirmed to separate man from all other animals in
1860, have all been demonstrated to be non-existent, and that the contrary
doctrine is now universally accepted and taught.

But there were other cases in which the wide structural gaps asserted to
exist between one group of animals and another were by no means fictitious;
and, when such structural breaks were real, Mr. Darwin could account for
them only by supposing that the intermediate forms which once existed had
become extinct. In a remarkable passage he says--

"We may thus account even for the distinctness of whole classes from each
other--for instance, of birds from all other vertebrate animals--by the
belief that many animal forms of life have been utterly lost, through which
the early progenitors of birds were formerly connected with the early
progenitors of the other vertebrate classes." [Footnote: _Origin of
Species_, p. 431.] Adverse criticism made merry over such suggestions as
these. Of course it was easy to get out of the difficulty by supposing
extinction; but where was the slightest evidence that such intermediate
forms between birds and reptiles as the hypothesis required ever existed?
And then probably followed a tirade upon this terrible forsaking of the
paths of "Baconian induction."

But the progress of knowledge has justified Mr. Darwin to an extent which
could hardly have been anticipated. In 1862, the specimen of
_Archæopteryx_, which, until the last two or three years, has remained
unique, was discovered; and it is an animal which, in its feathers and the
greater part of its organisation, is a veritable bird, while, in other
parts, it is as distinctly reptilian.

In 1868, I had the honour of bringing under your notice, in this theatre,
the results of investigations made, up to that time, into the anatomical
characters of certain ancient reptiles, which showed the nature of the
modifications in virtue of which the type of the quadrupedal reptile passed
into that of a bipedal bird; and abundant confirmatory evidence of the
justice of the conclusions which I then laid before you has since come to

In 1875, the discovery of the toothed birds of the cretaceous formation in
North America by Professor Marsh completed the series of transitional forms
between birds and reptiles, and removed Mr. Darwin's proposition that "many
animal forms of life have been utterly lost, through which the early
progenitors of birds were formerly connected with the early progenitors of
the other vertebrate classes," from the region of hypothesis to that of
demonstrable fact.

In 1859, there appeared to be a very sharp and clear hiatus between
vertebrated and invertebrated animals, not only in their structure, but,
what was more important, in their development. I do not think that we even
yet know the precise links of connection between the two; but the
investigations of Kowalewsky and others upon the development of
_Amphioxus_ and of the _Tunicata_ prove, beyond a doubt, that the
differences which were supposed to constitute a barrier between the two are
non-existent. There is no longer any difficulty in understanding how the
vertebrate type may have arisen from the invertebrate, though the full
proof of the manner in which the transition was actually effected may still
be lacking.

Again, in 1859, there appeared to be a no less sharp separation between the
two great groups of flowering and flowerless plants. It is only
subsequently that the series of remarkable investigations inaugurated by
Hofmeister has brought to light the extraordinary and altogether unexpected
modifications of the reproductive apparatus in the _Lycopodiaceæ_, the
_Rhizocarpeæ_, and the _Gymnospermeæ_, by which the ferns and the
mosses are gradually connected with the Phanerogamic division of the
vegetable world.

So, again, it is only since 1859 that we have acquired that wealth of
knowledge of the lowest forms of life which demonstrates the futility of
any attempt to separate the lowest plants from the lowest animals, and
shows that the two kingdoms of living nature have a common borderland which
belongs to both, or to neither.

Thus it will be observed that the whole tendency of biological
investigation, since 1859, has been in the direction of removing the
difficulties which the apparent breaks in the series created at that time;
and the recognition of gradation is the first step towards the acceptance
of evolution.

As another great factor in bringing about the change of opinion which has
taken place among naturalists, I count the astonishing progress which has
been made in the study of embryology. Twenty years ago, not only were we
devoid of any accurate knowledge of the mode of development of many groups
of animals and plants, but the methods of investigation were rude and
imperfect. At the present time, there is no important group of organic
beings the development of which has not been carefully studied; and the
modern methods of hardening and section-making enable the embryologist to
determine the nature of the process, in each case, with a degree of
minuteness and accuracy which is truly astonishing to those whose memories
carry them back to the beginnings of modern histology. And the results of
these embryological investigations are in complete harmony with the
requirements of the doctrine of evolution. The first beginnings of all the
higher forms of animal life are similar, and however diverse their adult
conditions, they start from a common foundation. Moreover, the process of
development of the animal or the plant from its primary egg, or germ, is a
true process of evolution--a progress from almost formless to more or less
highly organised matter, in virtue of the properties inherent in that

To those who are familiar with the process of development, all _a
priori_ objections to the doctrine of biological evolution appear
childish. Any one who has watched the gradual formation of a complicated
animal from the protoplasmic mass, which constitutes the essential element
of a frog's or a hen's egg, has had under his eyes sufficient evidence that
a similar evolution of the whole animal world from the like foundation is,
at any rate, possible.

Yet another product of investigation has largely contributed to the removal
of the objections to the doctrine of evolution current in 1859. It is the
proof afforded by successive discoveries that Mr. Darwin did not
over-estimate the imperfection of the geological record. No more striking
illustration of this is needed than a comparison of our knowledge of the
mammalian fauna of the Tertiary epoch in 1859 with its present condition.
M. Gaudry's researches on the fossils of Pikermi were published in 1868,
those of Messrs. Leidy, Marsh, and Cope, on the fossils of the Western
Territories of America, have appeared almost wholly since 1870, those of M.
Filhol on the phosphorites of Quercy in 1878. The general effect of these
investigations has been to introduce to us a multitude of extinct animals,
the existence of which was previously hardly suspected; just as if
zoologists were to become acquainted with a country, hitherto unknown, as
rich in novel forms of life as Brazil or South Africa once were to
Europeans. Indeed, the fossil fauna of the Western Territories of America
bid fair to exceed in interest and importance all other known Tertiary
deposits put together; and yet, with the exception of the case of the
American tertiaries, these investigations have extended over very limited
areas; and, at Pikermi, were confined to an extremely small space.

Such appear to me to be the chief events in the history of the progress of
knowledge during the last twenty years, which account for the changed
feeling with which the doctrine of evolution is at present regarded by
those who have followed the advance of biological science, in respect of
those problems which bear indirectly upon that doctrine.

But all this remains mere secondary evidence. It may remove dissent, but it
does not compel assent. Primary and direct evidence in favour of evolution
can be furnished only by palæontology. The geological record, so soon as it
approaches completeness, must, when properly questioned, yield either an
affirmative or a negative answer: if evolution has taken place, there will
its mark be left; if it has not taken place, there will lie its refutation.

What was the state of matters in 1859? Let us hear Mr. Darwin, who may be
trusted always to state the case against himself as strongly as possible.

"On this doctrine of the extermination of an infinitude of connecting links
between the living and extinct inhabitants of the world, and at each
successive period between the extinct and still older species, why is not
every geological formation charged with such links? Why does not every
collection of fossil remains afford plain evidence of the gradation and
mutation of the forms of life? We meet with no such evidence, and this is
the most obvious and plausible of the many objections which may be urged
against my theory." [Footnote: _Origin of Species_, ed. 1, p. 463.]

Nothing could have been more useful to the opposition than this
characteristically candid avowal, twisted as it immediately was into an
admission that the writer's views were contradicted by the facts of
palæontology. But, in fact, Mr. Darwin made no such admission. What he says
in effect is, not that palæontological evidence is against him, but that it
is not distinctly in his favour; and, without attempting to attenuate the
fact, he accounts for it by the scantiness and the imperfection of that

What is the state of the case now, when, as we have seen, the amount of our
knowledge respecting the mammalia of the Tertiary epoch is increased
fifty-fold, and in some directions even approaches completeness?

Simply this, that, if the doctrine of evolution had not existed,
palaeontologists must have invented it, so irresistibly is it forced upon
the mind by the study of the remains of the Tertiary mammalia which have
been brought to light since 1859.

Among the fossils of Pikermi, Gaudry found the successive stages by which
the ancient civets passed into the more modern hyænas; through the Tertiary
deposits of Western America, Marsh tracked the successive forms by which
the ancient stock of the horse has passed into its present form; and
innumerable less complete indications of the mode of evolution of other
groups of the higher mammalia have been obtained. In the remarkable memoir
on the phosphorites of Quercy, to which I have referred, M. Filhol
describes no fewer than seventeen varieties of the genus _Cynodictis_,
which fill up all the interval between the viverine animals and the
bear-like dog _Amphicyon_; nor do I know any solid ground of objection
to the supposition that, in this _Cynodictis-Amphicyon_ group, we have
the stock whence all the Viveridæ, Felidæ, Hyænidæ, Canidæ, and perhaps the
Procyonidæ and Ursidæ, of the present fauna have been evolved. On the
contrary, there is a great deal to be said in favour.

In the course of summing up his results, M. Filhol observes:--

"During the epoch of the phosphorites, great changes took place in animal
forms, and almost the same types as those which now exist became defined
from one another.

"Under the influence of natural conditions of which we have no exact
knowledge, though traces of them are discoverable, species have been
modified in a thousand ways: races have arisen which, becoming fixed, have
thus produced a corresponding number of secondary species."

In 1859, language of which this is an unintentional paraphrase, occurring
in the "Origin of Species," was scouted as wild speculation; at present, it
is a sober statement of the conclusions to which an acute and
critically-minded investigator is led by large and patient study of the
facts of palæontology. I venture to repeat what I have said before, that so
far as the animal world is concerned, evolution is no longer a speculation,
but a statement of historical fact. It takes its place alongside of those
accepted truths which must be reckoned with by philosophers of all schools.

Thus when, on the first day of October next, "The Origin of Species" comes
of age, the promise of its youth will be amply fulfilled; and we shall be
prepared to congratulate the venerated author of the book, not only that
the greatness of his achievement and its enduring influence upon the
progress of knowledge have won him a place beside our Harvey; but, still
more, that, like Harvey, he has lived long enough to outlast detraction and
opposition, and to see the stone that the builders rejected become the
head-stone of the corner.



[_Nature_, April 27th, 1882]

Very few, even among those who have taken the keenest interest in the
progress of the revolution in natural knowledge set afoot by the
publication of "The Origin of Species," and who have watched, not without
astonishment, the rapid and complete change which has been effected both
inside and outside the boundaries of the scientific world in the attitude
of men's minds towards the doctrines which are expounded in that great
work, can have been prepared for the extraordinary manifestation of
affectionate regard for the man, and of profound reverence for the
philosopher, which followed the announcement, on Thursday last, of the
death of Mr. Darwin.

Not only in these islands, where so many have felt the fascination of
personal contact with an intellect which had no superior, and with a
character which was even nobler than the intellect; but, in all parts of
the civilised world, it would seem that those whose business it is to feel
the pulse of nations and to know what interests the masses of mankind, were
well aware that thousands of their readers would think the world the poorer
for Darwin's death, and would dwell with eager interest upon every incident
of his history. In France, in Germany, in Austro-Hungary, in Italy, in the
United States, writers of all shades of opinion, for once unanimous, have
paid a willing tribute to the worth of our great countryman, ignored in
life by the official representatives of the kingdom, but laid in death
among his peers in Westminster Abbey by the will of the intelligence of the

It is not for us to allude to the sacred sorrows of the bereaved home at
Down; but it is no secret that, outside that domestic group, there are many
to whom Mr. Darwin's death is a wholly irreparable loss. And this not
merely because of his wonderfully genial, simple, and generous nature; his
cheerful and animated conversation, and the infinite variety and accuracy
of his information; but because the more one knew of him, the more he
seemed the incorporated ideal of a man of science. Acute as were his
reasoning powers, vast as was his knowledge, marvellous as was his
tenacious industry, under physical difficulties which would have converted
nine men out of ten into aimless invalids; it was not these qualities,
great as they were, which impressed those who were admitted to his intimacy
with involuntary veneration, but a certain intense and almost passionate
honesty by which all his thoughts and actions were irradiated, as by a
central fire.

It was this rarest and greatest of endowments which kept his vivid
imagination and great speculative powers within due bounds; which compelled
him to undertake the prodigious labours of original investigation and of
reading, upon which his published works are based; which made him accept
criticisms and suggestions from anybody and everybody, not only without
impatience, but with expressions of gratitude sometimes almost comically in
excess of their value; which led him to allow neither himself nor others to
be deceived by phrases, and to spare neither time nor pains in order to
obtain clear and distinct ideas upon every topic with which he occupied

One could not converse with Darwin without being reminded of Socrates.
There was the same desire to find some one wiser than himself; the same
belief in the sovereignty of reason; the same ready humour; the same
sympathetic interest in all the ways and works of men. But instead of
turning away from the problems of Nature as hopelessly insoluble, our
modern philosopher devoted his whole life to attacking them in the spirit
of Heraclitus and of Democritus, with results which are the substance of
which their speculations were anticipatory shadows.

The due appreciation, or even enumeration, of these results is neither
practicable nor desirable at this moment. There is a time for all things--a
time for glorying in our ever-extending conquests over the realm of Nature,
and a time for mourning over the heroes who have led us to victory.

None have fought better, and none have been more fortunate, than Charles
Darwin. He found a great truth trodden underfoot, reviled by bigots, and
ridiculed by all the world; he lived long enough to see it, chiefly by his
own efforts, irrefragably established in science, inseparably incorporated
with the common thoughts of men, and only hated and feared by those who
would revile, but dare not. What shall a man desire more than this? Once
more the image of Socrates rises unbidden, and the noble peroration of the
"Apology" rings in our ears as if it were Charles Darwin's farewell:--

"The hour of departure has arrived, and we go our ways--I to die and you to
live. Which is the better, God only knows."



[June 9th, 1885]

_Address by the President of the Royal Society, in the name of the
Memorial Committee, on handing over the statue of Darwin to H.R.H. the
Prince of Wales, as representative of the Trustees of the British

YOUR ROYAL HIGHNESS,--It is now three years since the announcement of the
death of our famous countryman, Charles Darwin, gave rise to a
manifestation of public feeling, not only in these realms, but throughout
the civilised world, which, if I mistake not, is without precedent in the
modest annals of scientific biography.

The causes of this deep and wide outburst of emotion are not far to seek.
We had lost one of these rare ministers and interpreters of Nature whose
names mark epochs in the advance of natural knowledge. For, whatever be the
ultimate verdict of posterity upon this or that opinion which Mr. Darwin
has propounded; whatever adumbrations or anticipations of his doctrines may
be found in the writings of his predecessors; the broad fact remains that,
since the publication and by reason of the publication, of "The Origin of
Species" the fundamental conceptions and the aims of the students of living
Nature have been completely changed. From that work has sprung a great
renewal, a true "instauratio magna" of the zoological and botanical

But the impulse thus given to scientific thought rapidly spread beyond the
ordinarily recognised limits of biology. Psychology, Ethics, Cosmology were
stirred to their foundations, and the "Origin of Species" proved itself to
be the fixed point which the general doctrine of evolution needed in order
to move the world. "Darwinism," in one form or another, sometimes strangely
distorted and mutilated, became an everyday topic of men's speech, the
object of an abundance both of vituperation and of praise, more often than
of serious study.

It is curious now to remember how largely, at first, the objectors
predominated; but considering the usual fate of new views, it is still more
curious to consider for how short a time the phase of vehement opposition
lasted. Before twenty years had passed, not only had the importance of Mr.
Darwin's work been fully recognised, but the world had discerned the
simple, earnest, generous character of the man, that shone through every
page of his writings.

I imagine that reflections such as these swept through the minds alike of
loving friends and of honourable antagonists when Mr. Darwin died; and that
they were at one in the desire to honour the memory of the man who, without
fear and without reproach, had successfully fought the hardest intellectual
battle of these days.

It was in satisfaction of these just and generous impulses that our great
naturalist's remains were deposited in Westminster Abbey; and that,
immediately afterwards, a public meeting, presided over by my lamented
predecessor, Mr. Spottiswoode, was held in the rooms of the Royal Society,
for the purpose of considering what further step should be taken towards
the same end.

It was resolved to invite subscriptions, with the view of erecting a statue
of Mr. Darwin in some suitable locality; and to devote any surplus to the
advancement of the biological sciences.

Contributions at once flowed in from Austria, Belgium, Brazil, Denmark,
France, Germany, Holland, Italy, Norway, Portugal, Russia, Spain, Sweden,
Switzerland, the United States, and the British Colonies, no less than from
all parts of the three kingdoms; and they came from all classes of the
community. To mention one interesting case, Sweden sent in 2296
subscriptions "from all sorts of people," as the distinguished man of
science who transmitted them wrote, "from the bishop to the seamstress, and
in sums from five pounds to two pence."

The Executive Committee has thus been enabled to carry out the objects
proposed. A "Darwin Fund" has been created, which is to be held in trust by
the Royal Society, and is to be employed in the promotion of biological

The execution of the statue was entrusted to Mr. Boehm; and I think that
those who had the good fortune to know Mr. Darwin personally will admire
the power of artistic divination which has enabled the sculptor to place
before us so very characteristic a likeness of one whom he had not seen.

It appeared to the Committee that, whether they regarded Mr. Darwin's
career or the requirements of a work of art, no site could be so
appropriate as this great hall, and they applied to the Trustees of the
British Museum for permission to erect it in its present position.

That permission was most cordially granted, and I am desired to tender the
best thanks of the Committee to the Trustees for their willingness to
accede to our wishes.

I also beg leave to offer the expression of our gratitude to your Royal
Highness for kindly consenting to represent the Trustees to-day. It only
remains for me, your Royal Highness, my Lords and Gentlemen, Trustees of
the British Museum, in the name of the Darwin Memorial Committee, to
request you to accept this statue of Charles Darwin.

We do not make this request for the mere sake of perpetuating a memory; for
so long as men occupy themselves with the pursuit of truth, the name of
Darwin runs no more risk of oblivion than does that of Copernicus, or that
of Harvey.

Nor, most assuredly, do we ask you to preserve the statue in its cynosural
position in this entrance-hall of our National Museum of Natural History as
evidence that Mr. Darwin's views have received your official sanction; for
science does not recognise such sanctions, and commits suicide when it
adopts a creed.

No; we beg you to cherish this Memorial as a symbol by which, as generation
after generation of students of Nature enter yonder door, they shall be
reminded of the ideal according to which they must shape their lives, if
they would turn to the best account the opportunities offered by the great
institution under your charge.


OBITUARY [Footnote: From the Obituary Notices of the _Proceedings of the
Royal Society_, vol. 44.]


Charles Robert Darwin was the fifth child and second son of Robert Waring
Darwin and Susannah Wedgwood, and was born on the 12th February, 1809, at
Shrewsbury, where his father was a physician in large practice.

Mrs. Robert Darwin died when her son Charles was only eight years old, and
he hardly remembered her. A daughter of the famous Josiah Wedgwood, who
created a new branch of the potter's art, and established the great works
of Etruria, could hardly fail to transmit important mental and moral
qualities to her children; and there is a solitary record of her direct
influence in the story told by a schoolfellow, who remembers Charles Darwin
"bringing a flower to school, and saying that his mother had taught him
how, by looking at the inside of the blossom, the name of the plant could
be discovered." (I., p. 28. [Footnote: The references throughout this
notice are to the _Life and Letters_, unless the contrary is expressly

The theory that men of genius derive their qualities from their mothers,
however, can hardly derive support from Charles Darwin's case, in the face
of the patent influence of his paternal forefathers. Dr. Darwin, indeed,
though a man of marked individuality of character, a quick and acute
observer, with much practical sagacity, is said not to have had a
scientific mind. But when his son adds that his father "formed a theory for
almost everything that occurred" (I., p. 20), he indicates a highly

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