exists in living things apart from Selection, and also much that may
very well have been preserved and so in a sense constituted by
Selection. Here the matter is likely to rest. There is a passage in
the sixth edition of the _Origin_ which has I think been overlooked.
On page 70 Darwin says, "The tuft of hair on the breast of the wild
turkey-cock cannot be of any use, and it is doubtful whether it can be
ornamental in the eyes of the female bird." This tuft of hair is a
most definite and unusual structure, and I am afraid that the remark
that it "cannot be of any use" may have been made inadvertently; but
it may have been intended, for in the first edition the usual
qualification was given and must therefore have been deliberately
excised. Anyhow I should like to think that Darwin did throw over that
tuft of hair, and that he felt relief when he had done so. Whether
however we have his great authority for such a course or not, I feel
quite sure that we shall be rightly interpreting the facts of nature
if we cease to expect to find purposefulness wherever we meet with
definite structures or patterns. Such things are, as often as not, I
suspect rather of the nature of tool-marks, mere incidents of
manufacture, benefiting their possessor not more than the wire-marks
in a sheet of paper, or the ribbing on the bottom of an oriental plate
renders those objects more attractive in our eyes.
If Variation may be in any way definite, the question once more
arises, may it not be definite in direction? The belief that it is has
had many supporters, from Lamarck onwards, who held that it was guided
by need, and others who, like Naegeli, while laying no emphasis on
need, yet were convinced that there was guidance of some kind. The
latter view under the name of "Orthogenesis," devised I believe by
Eimer, at the present day commends itself to some naturalists. The
objection to such a suggestion is of course that no fragment of real
evidence can be produced in its support. On the other hand, with the
experimental proof that variation consists largely in the unpacking
and repacking of an original complexity, it is not so certain as we
might like to think that the order of these events is not
predetermined.
For instance the original "pack" may have been made in such a way that
at the _n_th division of the germ-cells of a Sweet Pea a colour-factor
might be dropped, and that at the _n_+_n_th division the hooded
variety be given off, and so on. I see no ground whatever for holding
such a view, but in fairness the possibility should not be forgotten,
and in the light of modern research it scarcely looks so absurdly
improbable as before.
No one can survey the work of recent years without perceiving that
evolutionary orthodoxy developed too fast, and that a great deal has
got to come down; but this satisfaction at least remains, that in the
experimental methods which Mendel inaugurated, we have means of
reaching certainty in regard to the physiology of Heredity and
Variation upon which a more lasting structure may be built.
FOOTNOTES:
[Footnote 56: _Venus Physique, contenant deux Dissertations, l'une sur
l'origine des Hommes et des Animaux_; _Et l'autre sur l'origine des
Noirs_, La Haye, 1746, pp. 124 and 129. For an introduction to the
writings of Maupertuis I am indebted to an article by Professor
Lovejoy in _Popular Sci. Monthly_, 1902.]
[Footnote 57: For the fullest account of the views of these pioneers
of Evolution, see the works of Samuel Butler, especially _Evolution,
Old and New_ (2nd edit.) 1882. Butler's claims on behalf of Buffon
have met with some acceptance; but after reading what Butler has said,
and a considerable part of Buffon's own works, the word "hinted" seems
to me a sufficiently correct description of the part he played. It is
interesting to note that in the chapter on the Ass, which contains
some of his evolutionary passages, there is a reference to "_plusieurs
idees tres-elevees sur la generation_" contained in the Letters of
Maupertuis.]
[Footnote 58: See especially W. Lawrence, _Lectures on Physiology_,
London, 1823, pp. 213 f.]
[Footnote 59: See the chapter contributed to the _Life and Letters of
Charles Darwin_, II. p. 195. I do not clearly understand the sense in
which Darwin wrote (Autobiography, _ibid._ I. p. 87): "It has
sometimes been said that the success of the _Origin_ proved 'that the
subject was in the air,' or 'that men's minds were prepared for it.' I
do not think that this is strictly true, for I occasionally sounded
not a few naturalists, and never happened to come across a single one
who seemed to doubt about the permanence of species." This experience
may perhaps have been an accident due to Darwin's isolation. The
literature of the period abounds with indications of "critical
expectancy." A most interesting expression of that feeling is given in
the charming account of the "Early Days of Darwinism" by Alfred
Newton, _Macmillan's Magazine_, LVII. 1888, p. 241. He tells how in
1858 when spending a dreary summer in Iceland, he and his friend, the
ornithologist John Wolley, in default of active occupation, spent
their days in discussion. "Both of us taking a keen interest in
Natural History, it was but reasonable that a question, which in those
days was always coming up wherever two or more naturalists were
gathered together, should be continually recurring. That question was,
'What is a species?' and connected therewith was the other question,
'How did a species begin?'... Now we were of course fairly well
acquainted with what had been published on these subjects." He then
enumerates some of these publications, mentioning among others T.
Vernon Wollaston's _Variation of Species_--a work which has in my
opinion never been adequately appreciated. He proceeds: "Of course we
never arrived at anything like a solution of these problems, general
or special, but we felt very strongly that a solution ought to be
found, and that quickly, if the study of Botany and Zoology was to
make any great advance." He then describes how on his return home he
received the famous number of the _Linnean Journal_ on a certain
evening. "I sat up late that night to read it; and never shall I
forget the impression it made upon me. Herein was contained a
perfectly simple solution of all the difficulties which had been
troubling me for months past.... I went to bed satisfied that a
solution had been found."]
[Footnote 60: _Origin_, 6th edit. (1882), p. 421.]
[Footnote 61: Whatever be our estimate of the importance of Natural
Selection, in this we all agree. Samuel Butler, the most brilliant,
and by far the most interesting of Darwin's opponents--whose works are
at length emerging from oblivion--in his Preface (1882) to the 2nd
edition of _Evolution, Old and New_, repeats his earlier expression of
homage to one whom he had come to regard as an enemy: "To the end of
time, if the question be asked, 'Who taught people to believe in
Evolution?' the answer must be that it was Mr. Darwin. This is true,
and it is hard to see what palm of higher praise can be awarded to any
philosopher."]
[Footnote 62: _Life and Letters_, I. pp. 276 and 83.]
[Footnote 63: This isolation of the systematists is the one most
melancholy sequela of Darwinism. It seems an irony that we should read
in the peroration to the _Origin_ that when the Darwinian view is
accepted "Systematists will be able to pursue their labours as at
present; but they will not be incessantly haunted by the shadowy doubt
whether this or that form be a true species. This, I feel sure, and I
speak after experience, will be no slight relief. The endless disputes
whether or not some fifty species of British brambles are good species
will cease." _Origin_, 6th edit. (1882), p. 425. True they have ceased
to attract the attention of those who lead opinion, but anyone who
will turn to the literature of systematics will find that they have
not ceased in any other sense. Should there not be something
disquieting in the fact that among the workers who come most into
contact with specific differences, are to be found the only men who
have failed to be persuaded of the unreality of those differences?]
[Footnote 64: 6th edit. pp. 109 and 401. See Butler, _Essays on Life,
Art, and Science_, p. 265, reprinted 1908, and _Evolution, Old and
New_, chap. XXII. (2nd edit.), 1882.]
[Footnote 65: W. Lawrence was one of the few who consistently
maintained the contrary opinion. Prichard, who previously had
expressed himself in the same sense, does not, I believe, repeat these
views in his later writings, and there are signs that he came to
believe in the transmission of acquired habits. See Lawrence, _Lect.
Physiol._ 1823, pp. 436-437, 447. Prichard, Edin. Inaug. Disp. 1808
[not seen by me], quoted _ibid._ and _Nat. Hist. Man_, 1843, pp. 34
f.]
[Footnote 66: It is interesting to see how nearly Butler was led by
natural penetration, and from absolutely opposite conclusions, back to
this underlying truth: "So that each ovum when impregnate should be
considered not as descended from its ancestors, but as being a
continuation of the personality of every ovum in the chain of its
ancestry, which every ovum _it actually is_ quite as truly as the
octogenarian _is_ the same identity with the ovum from which he has
been developed. This process cannot stop short of the primordial cell,
which again will probably turn out to be but a brief resting-place. We
therefore prove each one of us to _be actually_ the primordial cell
which never died nor dies, but has differentiated itself into the life
of the world, all living beings whatever, being one with it and
members one of another," _Life and Habit_, 1878, p. 86.]
[Footnote 67: This view is no doubt contrary to the received opinion.
I am however interested to see it lately maintained by Driesch
(_Science and Philosophy of the Organism_, London, 1907, p. 233), and
from the recent observations of Godlewski it has received distinct
experimental support.]
[Footnote 68: In other words, the ova are each _either_ female, _or
male_ (i.e. non-female), but the sperms are all non-female.]
[Footnote 69: Morgan, _Proc. Soc. Exp. Biol. Med._ V. 1908, and von
Baehr, _Zool. Anz._ XXXII. p. 507, 1908.]
[Footnote 70: As Wilson has proved, the unpaired body is not a
universal feature even in those orders in which it has been observed.
Nearly allied types may differ. In some it is altogether unpaired. In
others it is paired with a body of much smaller size, and by selection
of various types all gradations can be demonstrated ranging to the
condition in which the members of the pair are indistinguishable from
each other.]
[Footnote 71: I have in view, for example, the marvellous and specific
phenomena of regeneration, and those discovered by the students of
"_Entwicklungsmechanik_." The circumstances of its occurrence here
preclude any suggestion that this regularity has been brought about by
the workings of Selection. The attempts thus to represent the
phenomena have resulted in mere parodies of scientific reasoning.]
[Footnote 72: _Vortraege ueber Viehzucht und Rassenerkenntniss_, p. 120,
Berlin, 1872.]
[Footnote 73: See Sutton, A. W., _Journ. Linn. Soc._ XXXVIII. p. 341,
1908.]
[Footnote 74: _Life and Habit_, London, p. 263, 1878]
IV
"THE DESCENT OF MAN"
BY G. SCHWALBE
_Professor of Anatomy in the University of Strassburg_
The problem of the origin of the human race, of the descent of man, is
ranked by Huxley in his epoch-making book _Man's Place in Nature_, as
the deepest with which biology has to concern itself, "the question of
questions,"--the problem which underlies all others. In the same
brilliant and lucid exposition, which appeared in 1863, soon after the
publication of Darwin's _Origin of Species_, Huxley stated his own
views in regard to this great problem. He tells us how the idea of a
natural descent of man gradually grew up in his mind. It was
especially the assertions of Owen in regard to the total difference
between the human and the simian brain that called forth strong
dissent from the great anatomist Huxley, and he easily succeeded in
showing that Owen's supposed differences had no real existence; he
even established, on the basis of his own anatomical investigations,
the proposition that the anatomical differences between the Marmoset
and the Chimpanzee are much greater than those between the Chimpanzee
and Man.
But why do we thus introduce the study of Darwin's _Descent of Man_,
which is to occupy us here, by insisting on the fact that Huxley had
taken the field in defence of the descent of man in 1863, while
Darwin's book on the subject did not appear till 1871? It is in order
that we may clearly understand how it happened that from this time
onwards Darwin and Huxley followed the same great aim in the most
intimate association.
Huxley and Darwin working at the same _Problema maximum_! Huxley
fiery, impetuous, eager for battle, contemptuous of the resistance of
a dull world, or energetically triumphing over it. Darwin calm,
weighing every problem slowly, letting it mature thoroughly,--not a
fighter, yet having the greater and more lasting influence by virtue
of his immense mass of critically sifted proofs. Darwin's friend,
Huxley, was the first to do him justice, to understand his nature, and
to find in it the reason why the detailed and carefully considered
book on the descent of man made its appearance so late. Huxley, always
generous, never thought of claiming priority for himself. In
enthusiastic language he tells how Darwin's immortal work, _The Origin
of Species_, first shed light for him on the problem of the descent of
man; the recognition of a _vera causa_ in the transformation of
species illuminated his thoughts as with a flash. He was now content
to leave what perplexed him, what he could not yet solve, as he says
himself, "in the mighty hands of Darwin." Happy in the bustle of
strife against old and deep-rooted prejudices, against intolerance and
superstition, he wielded his sharp weapons on Darwin's behalf; wearing
Darwin's armour he joyously overthrew adversary after adversary.
Darwin spoke of Huxley as his "general agent."[75] Huxley says of
himself "I am Darwin's bulldog."[76]
Thus Huxley openly acknowledged that it was Darwin's _Origin of
Species_ that first set the problem of the descent of man in its true
light, that made the question of the origin of the human race a
pressing one. That this was the logical consequence of his book Darwin
himself had long felt. He had been reproached with intentionally
shirking the application of his theory to Man. Let us hear what he
says on this point in his autobiography: "As soon as I had become, in
the year 1837 or 1838, convinced that species were mutable
productions, I could not avoid the belief that man must come under the
same law. Accordingly I collected notes on the subject for my own
satisfaction, and not for a long time with any intention of
publishing. Although in the 'Origin of Species' the derivation of any
particular species is never discussed, yet I thought it best, in order
_that no honourable man should accuse me of concealing my views_,[77]
to add that by the work 'light would be thrown on the origin of man
and his history.' It would have been useless and injurious to the
success of the book to have paraded, without giving any evidence, my
conviction with respect to his origin."[78]
In a letter written in January, 1860, to the Rev. L. Blomefield,
Darwin expresses himself in similar terms. "With respect to man, I am
very far from wishing to obtrude my belief; but I thought it dishonest
to quite conceal my opinion."[79]
The brief allusion in the _Origin of Species_ is so far from prominent
and so incidental that it was excusable to assume that Darwin had not
touched upon the descent of man in this work. It was solely the desire
to have his mass of evidence sufficiently complete, solely Darwin's
great characteristic of never publishing till he had carefully weighed
all aspects of his subject for years, solely, in short, his most
fastidious scientific conscience that restrained him from challenging
the world in 1859 with a book in which the theory of the descent of
man was fully set forth. Three years, frequently interrupted by
ill-health, were needed for the actual writing of the book:[80] the
first edition, which appeared in 1871, was followed in 1874 by a much
improved second edition, the preparation of which he very reluctantly
undertook.[81]
This, briefly, is the history of the work, which, with the _Origin of
Species_, marks an epoch in the history of biological sciences--the
work with which the cautious, peace-loving investigator ventured forth
from his contemplative life into the arena of strife and unrest, and
laid himself open to all the annoyances that deep-rooted belief and
prejudice, and the prevailing tendency of scientific thought at the
time could devise.
Darwin did not take this step lightly. Of great interest in this
connection is a letter written to Wallace on Dec. 22, 1857,[82] in
which he says, "You ask me whether I shall discuss 'man.' I think I
shall avoid the whole subject, as so surrounded with prejudices;
though I fully admit that it is the highest and most interesting
problem for the naturalist." But his conscientiousness compelled him
to state briefly his opinion on the subject in the _Origin of Species_
in 1859. Nevertheless he did not escape reproaches for having been so
reticent. This is unmistakably apparent from a letter to Fritz Mueller
dated Feb. 22 [1869?], in which he says: "I am thinking of writing a
little essay on the Origin of Mankind, as I have been taunted with
concealing my opinions."[83]
It might be thought that Darwin behaved thus hesitatingly, and was so
slow in deciding on the full publication of his collected material in
regard to the descent of man, because he had religious difficulties to
overcome.
But this was not the case, as we can see from his admirable confession
of faith, the publication of which we owe to his son Francis.[84]
Whoever wishes really to understand the lofty character of this great
man should read these immortal lines in which he unfolds to us in
simple and straightforward words the development of his conception of
the universe. He describes how, though he was still quite orthodox
during his voyage round the world on board the _Beagle_, he came
gradually to see, shortly afterwards (1836-1839) that the Old
Testament was no more to be trusted than the Sacred Books of the
Hindoos; the miracles by which Christianity is supported, the
discrepancies between the accounts in the different Gospels, gradually
led him to disbelieve in Christianity as a divine revelation. "Thus,"
he writes,[85] "disbelief crept over me at a very slow rate, but was
at last complete. The rate was so slow that I felt no distress." But
Darwin was too modest to presume to go beyond the limits laid down by
science. He wanted nothing more than to be able to go, freely and
unhampered by belief in authority or in the Bible, as far as human
knowledge could lead him. We learn this from the concluding words of
his chapter on religion "The mystery of the beginning of all things is
insoluble by us; and I for one must be content to remain an
Agnostic."[86]
Darwin was always very unwilling to give publicity to his views in
regard to religion. In a letter to Asa Gray on May 22, 1860,[87] he
declares that it is always painful to him to have to enter into
discussion of religious problems. He had, he said, no intention of
writing atheistically.
Finally, let us cite one characteristic sentence from a letter from
Darwin to C. Ridley[88] (Nov. 28, 1878). A clergyman, Dr. Pusey, had
asserted that Darwin had written the _Origin of Species_ with some
relation to theology. Darwin writes emphatically, "Many years ago when
I was collecting facts for the 'Origin,' my belief in what is called a
personal God was as firm as that of Dr. Pusey himself, and as to the
eternity of matter I never troubled myself about such insoluble
questions." The expression "many years ago" refers to the time of his
voyage round the world, as has already been pointed out. Darwin means
by this utterance that the views which had gradually developed in his
mind in regard to the origin of species were quite compatible with the
faith of the Church.
If we consider all these utterances of Darwin in regard to religion
and to his outlook on life (Weltanschauung), we shall see at least so
much, that religious reflection could in no way have influenced him in
regard to the writing and publishing of his book on _The Descent of
Man_. Darwin had early won for himself freedom of thought, and to this
freedom he remained true to the end of his life, uninfluenced by the
customs and opinions of the world around him.
Darwin was thus inwardly fortified and armed against the host of
calumnies, accusations, and attacks called forth by the publication of
the _Origin of Species_, and to an even greater extent by the
appearance of the _Descent of Man_. But in his defence he could rely
on the aid of a band of distinguished auxiliaries of the rarest
ability. His faithful confederate, Huxley, was joined by the botanist
Hooker, and, after longer resistance, by the famous geologist Lyell,
whose "conversion" afforded Darwin peculiar satisfaction. All three
took the field with enthusiasm in defence of the natural descent of
man. From Wallace, on the other hand, though he shared with him the
idea of natural selection, Darwin got no support in this matter.
Wallace expressed himself in a strange manner. He admitted everything
in regard to the morphological descent of man, but maintained, in a
mystic way, that something else, something of a spiritual nature must
have been added to what man inherited from his animal ancestors.
Darwin, whose esteem for Wallace was extraordinarily high, could not
understand how he could give utterance to such a mystical view in
regard to man; the idea seemed to him so "incredibly strange" that he
thought some one else must have added these sentences to Wallace's
paper.
Even now there are thinkers who, like Wallace, shrink from applying to
man the ultimate consequences of the theory of descent. The idea that
man is derived from ape-like forms is to them unpleasant and
humiliating.
So far I have been depicting the development of Darwin's work on the
descent of man. In what follows I shall endeavour to give a condensed
survey of the contents of the book.
It must at once be said that the contents of Darwin's work fall into
two parts, dealing with entirely different subjects. _The Descent of
Man_ includes a very detailed investigation in regard to secondary
sexual characters in the animal series, and on this investigation
Darwin founded a new theory, that of sexual selection. With
astonishing patience he gathered together an immense mass of material,
and showed, in regard to Arthropods and Vertebrates, the wide
distribution of secondary characters, which develop almost exclusively
in the male, and which enable him, on the one hand, to get the better
of his rivals in the struggle for the female by the greater perfection
of his weapons, and, on the other hand, to offer greater allurements
to the female through the higher development of decorative characters,
of song, or of scent-producing glands. The best equipped males will
thus crowd out the less well-equipped in the matter of reproduction,
and thus the relevant characters will be increased and perfected
through sexual selection. It is, of course, a necessary assumption
that these secondary sexual characters may be transmitted to the
female, although perhaps in rudimentary form.
As we have said, this story of sexual selection takes up a great deal
of space in Darwin's book, and it need only be considered here in so
far as Darwin applied it to the descent of man. To this latter problem
the whole of Part I is devoted, while Part III contains a discussion
of sexual selection in relation to man, and a general summary. Part
II treats of sexual selection in general, and may be disregarded in
our present study. Moreover, many interesting details must necessarily
be passed over in what follows, for want of space.
The first part of the _Descent of Man_ begins with an enumeration of
the proofs of the animal descent of man taken from the structure of
the human body. Darwin chiefly emphasises the fact that the human body
consists of the same organs and of the same tissues as those of the
other mammals; he shows also that man is subject to the same diseases
and tormented by the same parasites as the apes. He further dwells on
the general agreement exhibited by young embryonic forms, and he
illustrates this by two figures placed one above the other, one
representing a human embryo, after Ecker, the other a dog embryo,
after Bischoff.[89]