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DARWIN, AND AFTER DARWIN
II

POST-DARWINIAN QUESTIONS
HEREDITY AND UTILITY

BY THE SAME AUTHOR.

DARWIN, AND AFTER DARWIN. An Exposition of the
Darwinian Theory and a Discussion of Post-Darwinian
Questions.

1. The Darwinian Theory. With Portrait of Darwin.
460 pages. 125 illustrations. Cloth, fa. 00.

2. Post-Darwinian Questions. Edited by Prof. C.
Lloyd Morgan. With Portrait of G. J. Romanes.
338 pages. Cloth, $1.50.

3. Post-Darwinian Questions. Isolation and Phy-
siological Selection. Edited by Prof. C. Lloyd
Morgan. With Portrait of Mr. J. T. Gulick. 181
pages. Cloth, $1.00.

All three volumes together, $4.00 net.
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of Weismann. 236 pages. Cloth, $1.00.
THOUGHTS ON RELIGION. Edited by Charles Gore, M.A.,

Canon of Westminster. Third Edition. 184 pages. Cloth,

gilt top, $1.25.

THE OPEN COURT PUBLISHING COMPANY,

324 Dearborn Street, Chicago.

DARWIN, AND AFTER DARWIN

AN EXPOSITION OF THE DARWINIAN THEORY

AND A DISCUSSION OF

POST-DARWINIAN QUESTIONS

BY THE LATE

GEORGE JOHN^OMANES, M.A., LL.D., F.R.S.

Honorary Fellow of Gonville and Caius College, Cambridge

II

POST-DARWINIAN QUESITONS
HEREDITY AND UTILITY

THIRD EDITION.

THE OPEN COURT PUBLISHING COMPANY
1 906

CHAPTER I. CCFYRIGHTED BY

The Open pouRx Publishing Co.
CHICAGO, ILL., 1895.

Srf)e fLaftrsHit )9rr00

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PREFACE

As Its sub-title announces, the present volume is
mainly devoted to a consideration of those Post-
Darwinian Theories which involve fundamental
questions of Heredity and Utility.

As regards Heredity, I have restricted the discussion
almost exclusively to Professor Weismann's views,
partly because he is at present by far the most im-
portant writer upon this subject, and partly because
his views with regard to it raise with most distinctness
the issue which lies at the base of all Post-Darwinian
speculation touching this subject -the issue as to the
inheritance or non-inheritance of acquired characters.

My examination of the Utility question may well
seem to the general reader needlessly elaborate ; for
to such a reader it can scarcely fail to appear that
the doctrine which I am assailing has been broken
to fragments long before the criticism has drawn to
a close. But from my previous experience of the
hardness with which this fallacious doctrine dies,
I do not deem it safe to allow even one fragment of
it to remain, lest, hydra-like, it should re-develop into

a 3

vi Preface.

its formed proportions. And I can scarcely think
that naturalists who know the growing prevalence
of the doctrine, and who may have followed the issues
of previous discussions with regard to it, will accuse
me of being more over-zealous in my attempt to make
a full end thereof.

One more remark. It is a misfortune attending
the aim and scope of Part II that they bring me
into frequent discord with one or other of the most
eminent of Post- Darwinian writers— especially with
Mr. Wallace. But such is the case only because
the subject-matter of this volume is avowedly re-
stricted to debateable topics, and because I choose
those naturalists who are deservedly held in most
esteem to act spokesmen on behalf of such Post-
Darwinian views as appear to me doubtful or erro-
neous. Obviously, however, differences of opinion
on particular points ought not to be taken as imply-
ing any failure on my part to recognize the general
scientific authority of these men, or any inability
to appreciate their labours in the varied fields of
Biology.

G. J. R.

Christ Church, Oxford.

NOTE

Some time before his death Mr. Romanes decided
to publish those sections of his work which deal with
Heredity and Utility, as a separate volume, leaving
Isolation and Physiological Selection for the third and
concluding part of Darwitiy and after Darwin*

Most of the matter contained in this part was
already in type, but was not finally corrected for the
press. The alterations made therein are for the most
part verbal.

Chapter IV was type-written ; in it, too, no altera-
tions of any moment have been made.

For Chapters V and VI there were notes and iso-
lated paragraphs not yet arranged. I had promised
during his life to ^yrite for Mr. Romanes Chapter V
on the basis of these notes, extending it in such ways
as seemed to be desirable. In that case it would
have been revised and amended by the author and
received his final sanction. Death annulled this
friendly compact ; and since, had I written the
chapter myself, it could not receive that imprimatur
which would have given its chief value, I have decided

VIU

Note.

to arrange the material that passed into my hands
without adding anything of importance thereto. The
substance of Chapters V and VI is therefore entirely
the author's : even the phraseology is his ; the arrange-
ment only is by another hand.

Such parts of the Preface as more particularly
refer to Isolation and Physiological Selection are
reserved for publication in Part III. A year or more
must elapse before that part will be ready for
publication.

Mr. F. Howard Collins has, as a kindly tribute to
the memory of the author, read through the proofs.
Messrs. F. Darwin, F. Gal ton, H. Seebohm, and others,
have rendered incidental assistance. After much
search I am unable to give the references to one or
two passages.

I have allowed a too flattering reference to myself
to stand, in accordance with a particular injunction of
Mr. Romanes given shortly before that sad day on
which he died, leaving many to mourn the loss of
a personal friend most bright, lovable, and generous-
hearted, and thousands to regret that the hand which
had written so much for them would write for them
no more.

C. Ll. m.

University College, Bristol,
Aprils 1894.

CONTENTS

CHAPTER I.

PAGB

Introductory: The Darwinism of Darwin and of the

Post-Darwinian Schools i

CHAPTER II.
Characters as Hereditary and Acquired {Preliminary) 39

CHAPTER III.

Characters as Hereditary a^id Acquired {Continued).
A. Indirect evidence in favour of the Inheritance of Ac-
quired Characters 60

"&, Inherited effects of Use and of Disuse , • • • 95

CHAPTER IV.

Characters as Hereditary and Acquired {Continued).
C. Experimental evidence in favour of the Inheritance of

Acquired Char outers . . • • • .103

CHAPTER V.

Characters as Hereditary and Acquired {Continued).
A. and B. Direct and Indirect Evidence in favour of the

Non-inheritance of Acquired Characters . . -133
C. Experimental Evidence as to the Noninhetitanu 0f

Acquired Characters 143

X Contents.

CHAPTER VI.

VAGB

Characters as Hereditary and Acquired {Conclusion) 150

CHAPTER VII.
Characters as Adaptive and Specific . • • .159

CHAPTER VIII.

Characters as Adaptive and Specific (^Continued),

1. Climate aoo

II. Food 317

III. Sexual Selection 219

IV. Isolation 223

V. Laws of Growth • 226

CHAPTER IX.
Characters as Adaptive and Specific {Continued) . .328

CHAPTER X.

Characters as Adaptive and Specific {Concluded) , . 251

Summary 274

Appendix I. On Panmixia 291

Appendix II. On Characters as Adaptive and Specific . 307

Note A to Page 57 333

Note B to Page 89 337

LIST OF ILLUSTRATIONS

Portrait of George John Romanes .... Froniispieu

Diagram of Prof. Weismann's Theories 43

Fig. I. Guinea pigs, showing gangrene of ears due to injury of

restiform bodies Il8

Fig. 2. Old Irish Pig (after Richardson) . . • • . l88

Fig. 3. Skulls of Niata Ox and of Wild White Ox . . • 193

Fig. 4. Lower teeth of Orang (after Tomes) .... 267

DARWIN, AND AFTER DARWIN.

CHAPTER I.
Introductory : The Darwinism of Darwin,

AND OF THE POST-DARWINIAN SCHOOLS.

It is desirable to open this volume of the treatise
on Darwin and after Darwin by taking a brief
survey of the general theory of descent, first, as this
was held by Darwin himself, and next, as it is now
held by the several divergent schools of thought which
have arisen since Darwin's death.

The most important of the questions in debate is
one which I have already had occasion to mention,
while dealing, in historical order, with the objections
that were brought against the theory of natural
selection during the life-time of Darwin ^. Here, how-
ever, we must consider it somewhat more in detail,
and justify by quotation what was previously said
regarding the very definite nature of his utterances
upon the matter. This question is whether natural
selection has been the sole, or but the main, cause
of organic evolution.

* Part I, pp. 253-256.
II. I!

2 DarwiUy and after Darwin,

Must we regard survival of the fittest as the one
and only principle which has been concerned in the
progressive modification of living forms, or are we to
suppose that this great and leading principle has been
assisted by other and subordinate principles, without
the co-operation of which the results, as presented in
the animal and vegetable kingdoms, could not have
been effected ? Now Darwin's answer to this question
was distinct and unequivocal. He stoutly resisted
the doctrine that natural selection was to be regarded
as the only cause of organic evolution. On the other
hand, this opinion was — and still continues to be —
persistently maintained by Mr. Wallace; and it con-
stitutes the source of all the differences between his
views and those of Darwin. Moreover, up to the time
of Darwin's death, Mr. Wallace was absolutely alone
in maintaining this opinion : the whole body of
scientific thought throughout the world being against
him ; for it was deemed improbable that, in the
enormously complex and endlessly varied processes
of organic evolution, only a single principle should be
everywhere and exclusively concerned ^ But since
Darwin's death there has been a great revolution of
biological thought in favour of Mr. Wallace's opinion.
And the reason for this revolution has been, that
his doctrine of natural selection as the sole cause
of organic evolution has received the corroborative
support of Professor Weismann's theory of heredity —
which has been more or less cordially embraced by
a certain section of evolutionists, and which appears to
carry the doctrine in question as a logical corollary, so
far, at all events, as adaptive structures are concerned.

' Contributions to the Theory of Natural Selection, p. 47.

Introduction. 3

Now in this opening chapter we shall have to do
merely with a setting forth of Darwin's opinion :
we are not considering how far that opinion ought
to be regarded as having been in any measure dis-
placed by the results of more recent progress. Such,
then, being the only matter which here concerns us,
I will supply a few brief quotations, to show how
unequivocally Darwin has stated his views. First,
we may take what he says upon the " Lamarckian
factors ^ ; " and next we may consider what he says
with regard to other factors, or, in general, upon
natural selection not being the sole cause of organic
evolution.

'* Changed habits produce an inherited effect, as in the period
of the flowering of plants when transported from one climate to
another. With animals the increased use or disuse of parts has
had a more marked influence ^"

" There can be no doubt, from the facts given in this chapter,
that extremely slight changes in the conditions of life sometimes,
probably often, act in a definite manner on our domesticated
productions ; and, as the action of changed conditions in
causing indefinite variability is accumulative, so it may be with
their definite action. Hence considerable and definite modifi-
cations of structure probably follow from altered conditions
acting during long series of generations V

" How, again, can we explain the inherited effects of the use
and disuse of particular organs ? The domesticated duck flies

' So far as we shall be concerned with them throughout this trea-
tise, the "Lamarckian factors" consist in the supposed transmission
of acquired characters, whether the latter be due to the diiect influence
of external conditions of life on the one hand, or to the inherited effects of
use and disuse on the other. For the phrase " inherited effects of use and
disuse," I shall frequently employ the term "use-inheritance," which has
been coined by Mr. Piatt Ball as a more convenient expression.

^ Origin of Species, 6th ed. p. 8.

* Variation &c. 2nd ed. ii. p. 280.

B 2

4 Darwin, and after Darwin,

less and walks more than the wild duck, and its limb bones
have become diminished and increased in a corresponding
manner in comparison with those of the wild duck. A horse is
trained to certain paces, and the colt inherits similar consensual
movements. The domesticated rabbit becomes tame from
dose confinement; the dog, intelligent from associating with
man; the retriever is taught to fetch and carry; and these
mental endowments and bodily powers are all inherited
Nothing in the whole circuit of physiology is more wonderfu..
How can the use or disuse of a particular limb or of the bram
affect a small aggregate of reproductive cells, seated in a distant
part of the body, in such a manner that the being developed
from these cells inherits the characters of either one or both
parents ? ... In the chapters devoted to inheritance, it was
shown that a multitude of newly acquired characters, whether
injurious or beneficial, whether of the lowest or highest vital
importance, are often faithfully transmitted '.''

"When discussing special cases, Mr. Mivart passes over the
effects of the increased use and disuse of parts, which I have
always maintained to be highly important, and have treated in
my * Variation under Domestication' at greater length than,
as I believe, any other writer . '

So much for the matured opinion of Darwin touching
the validity of the theory of use-inheritance. Turning
now to his opinion on the question whether or not
there are yet any further factors concerned in the
process of organic evolution, I think it will be sufficient
to quote a single passage from the Origin of Species.
The first paragraph of the " Conclusion " is devoted
to a rhumi of his views upon this matter, and con-
sists of the following most emphatic words.

" I have now recapitulated the facts and considerations which
have thoroughly convinced me that species have been modified,
during a long course of descent. This has been effected chiefly
through the natural seleclion of numerous successive, slight,

* Variation &c. ii. p. 367. " Origin of Specits, p. 176.

Introduction. 5

fevourable variations; aided in an important manner by the
inherited effects of the use and disuse of parts ; and in an un-
important manner, that is in relation to adaptive structures,
whether past or present, by the direct action of external con-
ditions, and by variations which seem to us in our ignorance to
arise spontaneously. It appears that I formerly underrated the
frequency and value of these latter forms of variation, as leading
to permanent modifications of structure independently of natural
selection. But as my conclusions have lately been much mis-
represented, and it has been stated that I attribute the modifica-
tion of species exclusively to natural selection, I may be permitted
to remark that in the first edition of this work, and subsequently,
I placed in a most conspicuous position — namely, at the close
of the Introduction -the following words : * 1 am convinced that
natural selection has been the main, but not the exclusive means
of modification.' This has been of no avail. Great is the
power of steady misrepresentation ; but the history of science
shows that fortunately this power does not long endure."

In the whole range of Darwin's writings there
cannot be found a passage so strongly worded as
this : it presents the only note of bitterness in all
the thousands of pages which he has published.
Therefore I do not think it is necessary to supply
any further quotations for the purpose of proving
the state of his opinion upon the point in question.
But, be it carefully noted, from this great or radical
difference of opinion between the joint originators of
the theory of natural selection, all their other differ-
ences of opinion arise ; and seeing that since the
death of Darwin a large number of naturalists have
gone over to the side of Wallace, it seems desirable
here to state categorically what these other or sequent
points of difference are. Without at present discuss-
ing them, therefore. I will merely set them out in a
tabular form, in order that a clear perception may be

Darwiny and after Darwin,

gained of their logical connexion with this primary
point of difference.

Thetheory of Natural Selection
according to Darwin.

Natural Selection has been
the main means of modifica-
tion, not excepting the case of
Man.

{a) Therefore it is a question
of evidence whether the La-
marckian factors have co-
operated.

{b) Neither all species, nor,
a fortiori^ all specific char-
acters, have been due to
natural selection.

(c) Thus the principle of
Utility is not of universal ap-
plication, even where species
are concerned.

{d) Thus, also, the sugges-
tion as to Sexual Selection, or
any other supplementary cause
of modification, may be enter-
tained ; and, as in the case of
the Lamarckian factors, it is a
question of evidence whether,
or how far, they have co-
operated.

{e) No detriment arises to
the theory of natural selection
as a theory of the origin of
species by entertaining the
possibility, or the probability,
of supplementary factors.

(/) Cross-sterility in species
cannot possibly be due to
natural selection.

Thetheory of Natural Selection
according to Wallace.

Natural Selection has been
the sole means of modification,
excepting in the case of Man.

(at) Therefore it is ante-
cedently impossible that the
Lamarckian factors can have
co-operated.

[b) Not only all species, but
all specific characters, must
necessarily have been due to
natural selection.

{c) Thus the principle of
Utility must necessarily be of
universal application, where
species are concerned.

{d) Thus, also, the sugges-
tion as to Sexual Selection, or
of any other supplementary
cause of modification, must be
ruled out ; and, as in the case
of the Lamarckian factors,
their co-operation deemed im-
possible.

{e) The possibility — and, a
fort tori \.h.t probability — of any
supplementary factors cannot
be entertained without serious
detriment to the theory of
natural selection, as a theory
of the origin of species.

(/) Cross-sterility in species
is probably due to natural
selection ^

' This, to the best of my judgement, is the fairest extract that I can
give of Mr. Wallace's most recently published opinions on the points in

Introduction. 7

As it will be my endeavour in the ensuing chapters
to consider the rights and the wrongs of these anti-
thetical propositions, I may reserve further quotations
from Darwin's works, which will show that the above
is a correct epitome of his views as contrasted with
those of Wallace and the Neo-Darwinian school of
Weismann. But here, where the object is merely
a statement of Darwin's theory touching the points
in which it differs from those of Wallace and Weis-
mann, it will be sufficient to set forth these points of
difference in another and somewhat fuller form. So
far then as we are at present concerned, the fol-
lowing are the matters of doctrine which have been
clearly, emphatically, repeatedly, and uniformly ex-
pressed throughout the whole range of Darwin's
writings.

1. That natural selection has been the main means
of modification.

2. That, nevertheless, it has not been the only
means ; but has been supplemented or assisted by the
co-operation of other causes.

3. That the most " important '* of these other causes
has been the inheritance of functionally-produced
modifications (use-inheritance); but this only because
the transmission of such modifications to progeny must
always have had immediate reference to adaptive
ends, as distinguished from merely useless change.

4. That there are sundry other causes which lead

question. [In particular as regards (a) see Darwinism pp. 435-6.] But
with regard to some of them, his expression of opinion is not always
consistent, as we shall find in detail later on. Besides, I am here taking
Mr. Wallace as representative of the Neo- Darwinian school, one or other
prominent member of which has given emphatic expression to each of the
above propositions.

8 Darwifiy and after Darwin.

to merely useless change — in particular, "the direct
action of external conditions and variations which
seem to us in our ignorance to arise spontaneously."

5. Hence, that the " principle of utility," far from
being of universal occurrence in the sphere of animate
nature, is only of what may be termed highly general
occurrence ; and, therefore, that certain other advocates
of the theory of natural selection were mistaken in
representing the universality of this principle as
following by way of necessary consequence from that
theory.

6. Cross-sterility in species cannot possibly be due
to natural selection ; but everywhere arises as a result
of some physiological change having exclusive refer-
ence to the sexual system — a change which is
probably everywhere due to the same cause, although
what this cause could be Darwin was confessedly
unable to suggest

Such, then, was the theory of evolution as held by
Darwin, so far as the points at present before us are
concerned. And, it may now be added, that the
longer he lived, and the more he pondered these
points, the less exclusive was the role which he as-
signed to natural selection, and the more importance
did he attribute to the supplementary factors above
named. This admits of being easily demonstrated
by comparing successive editions of his works ; a
method adopted by Mr. Herbert Spencer in his
essay on the Factors of Organic Evolution.

My object in thus clearly defining Darwin's attitude
regarding these sundry points is twofold.

In the first place, with regard to merely historical
accuracy, it appears to me undesirable that naturalists

Introduction. 9

should endeavour to hide certain parts of Darwin's
teaching, and give undue prominence to others. In
the second place, it appears to me still more un-
desirable that this should be done — as it usually is
done — for the purpose of making it appear that
Darwin's teaching did not really differ very much
from that of Wallace and Weismann on the important
points in question. I myself believe that Darwin's
judgement with regard to all these points will
eventually prove more sound and accurate than
that of any of the recent would-be improvers upon
his system ; but even apart from this opinion
of my own it is undesirable that Darwin's views
should be misrepresented, whether the misrepre-
sentation be due to any unfavourable bias against one
side of his teaching, or to sheer carelessness in the
reading of his books. Yet the new school of evo-
lutionists, to which allusion has now so frequently been
made, speak of their own modifications of Darwin's
teaching as "pure Darwinism," in contradistinction
to what they call " Lamarckism." In other words,
they represent the principles of '• Darwinism " as
standing in some kind of opposition to those of
'• Lamarckism " : the Darwinian principle of natural
selection, they think, is in itself enough to account for
all the facts of adaptation in organic nature. There-
fore they are eager to dispense with the Lamarckian
principle of the inherited effects of use and disuse,
together with the direct influence of external conditions
of life, and all or any other causes of modification which
either have been, or in the future may possibly be,
suggested. Now, of course, there is no reason why
any one should not hold these or any other opinions

lo Darwin f and after Darwin,

to which his own independent study of natural science
may lead him ; but it appears to me that there is
the very strongest reason why any one who deviates
from the carefully formed opinions of such a man
as Darwin, should above all things be careful to
be absolutely fair in his representations of them;
he should be scrupulously jealous, so to speak, of
not letting it appear that he is unjustifiably throwing
over his own opinions the authority of Darwin's
name.

But in the present case, as we have seen, not only
do the Neo-Darwinians strain the teachings of Dar-
win ; they positively reverse those teachings — repre-
senting as anti-Darwinian the whole of one side of
Darwin's system, and calling those who continue to
accept that system in its entirety by the name
" Lamarckians " I know it is sometimes said by
members of this school, that in his utilization of
Lamarckian principles as accessory to his own,
Darwin was actuated by motives of "generosity." But
a more preposterous suggestion could not well be
made. We may fearlessly challenge any one who
speaks or writes in such a way, to show any other
instance where Darwin's great generosity of dis-
position had the effect of influencing by one hair's
breadth his still greater loyalty to truth. Moreover,
and with special regard to this particular case, I
would point out that in no one of his many allu-
sions to, and often lengthy dicussions of, these so-
called Lamarckian principles, does he ever once
introduce the name of Lamarck; while, on the other
hand, in the only places where he does so— whether
in his books or in his now published letters— he

Introduction. ii

does so in order to express an almost contemptuous
dissatisfaction, and a total absence of obligation.
Hence, having regard to the "generosity" with
which he always acknowledged obligations, there
can be no reasonable doubt that Darwin was not in
the smallest degree influenced by the speculative
writings of Lamarck ; or that, even if Lamarck had
never lived, the Origin of Species would have differed
in any single particular from the form in which it
now stands. Finally, it must not be forgotten that
Darwin's acceptance of the theory of use- inherit-
ance was vitally essential to his theory of Pangenesis
— that 'beloved child" over which he had *' thought
so much as to have lost all power of judging it^."

What has just been said touching the relations
between Darwin's theory and that of Lamarck,
applies with equal force to the relations between
Darwin's theory and any other theory appertain-
ing to evolution which has already been, or may
hereafter be, propounded. Yet so greatly have
some of the Neo-Darwinians misunderstood the teach-
ings of Darwin, that they represent as "Darwinian
heresy" any suggestions in the way of factors "supple-
mentary to," or '^co-operative with" natural selection.
Of course, if these naturalists were to avow themselves
followers of Wallace, instead of followers of Darwin,
they would be perfectly justified in repudiating any
such suggestions as, ipso facto heretical. But, as we
have now seen, through all his life Darwin differed
from Wallace with regard to this very point ; and
therefore, unlike Wallace, he was always ready to en-
tertain " additional suggestions " regarding the causes

' Life and Letters y vol. iii. pp. 72 and 75.

la DarwiUy and after Darwin.

of organic evolution — several of which, indeed, he
himself supplied. Hence we arrive at this curious
state of matters. Those biologists who of late years
have been led by Weismann to adopt the opinions of
Wallace, represent as anti-Darwinian the opinions of
other biologists who still adhere to the unadulterated
doctrines of Darwin. Weismann's Essays on Heredity
(which argue that natural selection is the only pos-
sible cause of adaptive modification) and Wallace's
work on Darwmism (which in all the respects
where any charge of " heresy " is concerned directly
contradicts the doctrine of Darwin) — these are the
writings which are now habitually represented by the
Neo-Darwinians as setting forth the views of
Darwin in their 'pure" form. The result is that,
both in conversation and in the press, we habitually
meet with complete inversions of the truth, which
show the state of confusion into which a very simple
matter has been wrought by the eagerness of certain
naturalists to identify the views of Darwin with those
of Wallace and Weismann. But we may easily
escape this confusion, if we remember that wherever
in the writings of these naturalists there occur such
phrases as "pure Darwinism" we are to understand
pure Wallaceism, or the pure theory of natural
selection to the exclusion of any supplementary
theory. Therefore it is that for the sake of clearness
I coined, several years ago, the terms " Neo- Darwin-
ian " and " Ultra- Darwinian " whereby to designate
the school in question.

So much, then, for the Darwinism of Darwin, as
contrasted with the Darwinism of Wallace, or, what

Introduction, 13

is the same thing, of the Neo-Darwinian school of
Weismann. Next we may turn, by way of antithesis,
to the so-called '* Neo-Lamarckian '* school of the
United States. For, by a curious irony of fate, while
the Neo-Darwinian school is in Europe seeking to
out-Darwin Darwin by assigning an exclusive pre-
rogative to natural selection in both kingdoms of
animate nature, the Neo-Lamarckian school is in
America endeavouring to reform Darwinism in
precisely the opposite direction — viz. by transferring
the sovereignty from natural selection to the
principles of Lamarck. Without denying to natural
selection a more or less important part in the process
of organic evolution, members of this school believe
that much greater importance ought to be assigned
to the inherited effects of use and disuse than was
assigned to these agencies by Darwin. Perhaps
this noteworthy state of affairs, within a decade of
Darwin's death, may lead us to anticipate that his
judgement — standing, as it does, between these two
extremes — will eventually provie the most accurate
of all, with respect to the relative importance of
these factors of evolution. But, be this as it may,
I must now offer a few remarks upon the present
position of the matter.

In the first place, to any one who (with Darwin and
against Weismann) admits not only the abstract pos-
sibility, but an actual working, of the Lamarckian
factors, it becomes difficult to determine, even
approximately, the degrees of value which ought to
be ascribed to them and to natural selection respec-
tively. For, since the results are in both cases identical
in kind (as. adaptive changes of organic types), where

14 Darwin^ and after Darwin,

both sets of causes are supposed to be in operation
together, we have no means of estimating the relative
shares which they have had in bringing about these
results. Of course there are large numbers of cases
where it cannot possibly be supposed that the
Lamarckian factors have taken any part at all in pro-
ducing the observed effects ; and therefore in such cases
there is almost full agreement among evolutionists in
theoretically ascribing such effects to the exclusive
agency of natural selection. Of such, for instance, are
the facts of protective colouring, of mimicry, of the
growth of parts which, although useful, are never
active (e.g. shells of mollusks. hard coverings of seeds),
and so on. But in the majority of cases where
adaptive structures are concerned, there is no means
of discriminating between the influences of the
Lamarckian and the Darwinian factors. Conse-
quently, if by the Neo-Lamarckian school we under-
stand all those naturalists who assign any higher
importance to the Lamarckian factors than was
assigned to them by Darwin, we may observe that
members of this school differ very greatly among
themselves as to the degree of importance that ought
to be assigned. On the one hand we have, in Europe,
Giard, Perrier, and Eimer, who stand nearer to Dar-
win than do a number of the American representatives
— of whom the most prominent are Cope, Osborn,
Packard, Hyatt, Brooks, Ryder, and Dall. The most
extreme of these is Professor Cope, whose collection
of essays entitled The Origin of the Fittest, as well as
his more recent and elaborate monograph on The
Development of the Hard Parts of the Mammalia,
represent what appears even to some other members

Introduction, 15

of his school an extravagant estimate of the impor-
tance of Lamarckian principles.

But the most novel, and in many respects the
most remarkable school of what may be termed
Anti-selectionists is one which is now (1894) rapidly
increasing both in numbers and in weight, not only
in the New World, but also in Germany, and to a
lesser extent, in Great Britain.

This school, without being either Lamarckian or
Darwinian (for its individual members differ widely
from one another in these respects) maintains a
principle which it deems of more importance than
either use-inheritance or natural selection. This prin-
ciple it calls Self-adaptation. It is chiefly botanists
who constitute this school, and its principal representa-
tives, in regard to authority, are Sachs, Pfeffer and
Henslow.

Apart from topics which are to be dealt with in
subsequent chapters, the only matters of much impor-
tance which have been raised in the Post-Darwinian
period are those presented by the theories of Geddes,
Cope. Hyatt, and others, and certain more or less
novel ideas set forth in Wallace's Darwinism.

Mr. Geddes has propounded a new theory of the
origin of species, which in his judgement supersedes to
a large extent the theory of natural selection. He has
also, in conjunction with Mr. Thomson, propounded
a theory of the origin of sex. For my own part, I
cannot see that these views embody any principles
or suggestions of a sufficiently definite kind to
constitute them theories at all. In this respect the
views of Mr. Geddes resemble those of Professors
Cope, Hyatt, and others, on what they term *the

i6 Darwin, and after Darwin,

law of acceleration and retardation." In all these
cases, so far as I can see, the so-called explanations
are not in fact any explanations ; but either a mere
re-statement of the facts, or else an enunciation of
more or less meaningless propositions. Thus, when
it is said that the evolution of any given type has
been due to the " acceleration of growth-force " with
respect to some structures, and the "retardation of
growth - force " with respect to others, it appears
evident that we have not any real explanation in terms
of causality; we have only the form of an explanation
in the terms of a proposition. All that has been done
is to express the fact of evolution in somewhat obscure
phraseology, since the very thing we want to know
about this fact is — What are the causes of it as a fact.
or the reasons which have led to the increase of some
of the parts of any given type, and the concomitant
decrease of others ? It is merely the facts themselves
that are again presented by saying that the develop-
ment has been in the one case accelerated, while in
the other it has been retarded ^.

So much for what may be termed this New
World theory of the origin of species: it is a mere
re-statement of the facts. Mr. Geddes' theory, on the

^ Take, for example, the following, which is a fair epitome of the
whole : — ** I believe that this is the simplest mode of stating and
explaining the law of variation ; that some forms acquire something
which their parents did not possess; and that those which acquire
something additional have to pass through more numerous stai,'es than
their ancestors; and those which lose something pass through fewer
stages than their ancestors ; and these processes are expressed by the
terms "acceleration " and "retardation " {Origin of the Fittest, pp 125,
226, and 297). Even if this be "the simplest mode of stating the law
of variation," it obviously does nothing in the way of explaining the
law.

Introduction. 17

other hand, although more than a mere re-statement
of the facts, appears to me too vague to be of any-
explanatory service. His view is that organic evolu-
tion has everywhere depended upon an antagonism,
within the limits of the same organism, between the
processes of nutrition and those of reproduction. But
although he is thus able hypothetically to explain
certain facts — such as the shortening of a flower-spike
into a composite flower — the suggestion is obviously
inadequate to meet, even hypothetically, most of the
facts of organic evolution, and especially the develop-
ment of adaptive structures. Therefore, it seems to me,
we may dismiss it even as regards the comparatively
few facts which it might conceivably explain— seeing
that these same facts may be equally well explained
by the causes which are already known to operate
in other cases. For it is the business of natural
selection to ensure that there shall nowhere be any
needless expenditure of vital energy, and, conse-
quently, that everywhere the balance between nutrition
and reproduction shall be most profitably adjusted.

Similarly with respect to the theory of the Origin
of Sex, I am unable to perceive even this much of
scientific relevancy. As stated by its authors the
theory is that the female is everywhere *' anabolic,"
as compared with the male, which is " katabolic." By
anabolic is meant comparative inactivity of proto-
plasmic change due to a nutritive winding up of
molecular constitution, while by katabolic is meant
the opposite condition of comparative activity due to
a dynamic running down of molecular constitution.
How, then, can the origin of sex be explained, or the
causes which led to the difl'erentiation of the sexes be

II. c

i8 Darwin^ and after Darwin,

shown, by saying that the one sex is anabolic and the
other katabolic ? In so far as these verbal statements
serve to express what is said to be a general fact —
namely, that the female sexual elements are less
mobile than the male — they merely serve to re-state
this general fact in terminology which, as the authors
themselves observe, is "unquestionably ugly." But
in so far as any question of origin or causality is con-
cerned, it appears to me that there is absolutely no
meaning in such statements. They belong to the
order of merely formal explanations, as when it is said
that the toxic qualities of morphia are due to this
drug possessing a soporific character.

Much the same, in my opinion, has to be said of
the Rev. G. Henslow's theory of the origin of species
by what he terms "self-adaptation." Stated briefly
his view is that there is no sufficient evidence of
natural selection as a vera causa, while there is very
abundant evidence of adjustments occurring without
it, first in individual organisms, and next, by inherit-
ance of acquired characters, in species. Now, much
that he says in criticism of the selection theory is of
considerable interest as such ; but when we pass
from the critical to the constructive portions of his
books and papers, we again meet with the want of
clearness in thought between a statement of facts
in terms of a proposition, and an explanation of
them in those of causality. Indeed, I understand
from private correspondence, that Mr. Henslow him-
self admits the validity of this criticism ; for in
answer to my questions, — '* How does Self-adapta-
tion work in each case, and why should protoplasm
be able to adapt itself into the millions of diverse

Introduction, 19

mechanisms in nature ? '* — he writes, " Self-adaptation
does not profess to be a vera causa at all ; for the
true causes of variation can only be found in the
answer to your [above] questions, and I must say
at once, these questions cannot be answered'^ That
is, they cannot be answered on the hypothesis of
self-adaptation, which is therefore a statement of
the facts of adaptation as distinguished from an
explanation of them. Nevertheless, two things have
here to be noted. In the first place, the statement
of facts which Mr. Henslow has collected is of con-
siderable theoretical importance as tending to show
that there are probably causes of an internal kind
(i.e. other than natural selection) which have been
largely concerned in the adaptive modification of
plants. And, in the second place, it is not quite true
that the theory of self-adaptation is, as its author
says in the sentences above quoted, a mere statement
of the facts of adaptation, without any attempt at
explaining their causes. For in his published words
he does attempt to do so^ And, although I think
his attempt is a conspicuous failure, I ought in fair-
ness to give examples of it. His books are almost
exclusively concerned in an application of his theory
to the mechanisms of flowers for securing their own
fertilization. These mechanisms he ascribes, in the
case of entomophylous flowers, to the "thrusts,"
" strains," and other '* irritations " supplied to the
flowers by their insect visitors, and consequent "reac-
tions " of the vegetable " protoplasm." But no
attempt is made to show why these " reactions "

* Floral Structures (Internat. Sc. Ser. Ixiv. 1888): The Making of
Flowers (Romance of Science Ser. 189 1) ; and Linn. Soc. Papers 1893-4.

C 2

20 Darwin, and after Darwin.

should be of an adaptive kind, so as to build up
the millions of diverse and often elaborate mechanisms
in question — including not only forms and move-
ments, but also colours, odours, and secretions. For
my own part I confess that, even granting to an
ultra- Lamarcki an extent the inheritance of acquired
characters, I could conceive of "self-adaptation" alone
producing all such innumerable and diversified adjust-
ments only after seeing, with Cardinal Newman, an
angel in every flower. Yet Mr. Henslow somewhat
vehemently repudiates any association between his
theory and that of teleology.

On the whole, then, I regard all the works which
are here classed together (those by Cope, Geddes,
and Henslow), as resembling one another both in
their merits and defects. Their common merits lie
in their erudition and much of their criticism, while
their common defects consist on the one hand in not
sufficiently distinguishing between mere statements
and real explanations of facts, and, on the other, in
not perceiving that the theories severally suggested
as substitutes for that of natural selection, even if
they be granted true, could be accepted only as
co-operative factors, and by no stretch of logic as
substitutes.

Turning now to Mr. Wallace's work on Darwinism^
we have to notice, in the first place, that its doctrine
differs from " Darwinism " in regard to the important
dogma which it is the leading purpose of that work
to sustain — namely, that "the law of utility" is, to all
intents and purposes, universal, with the result that
natural selection is virtually the only cause of organic

Introduction, 2i

evolution. I say "to all intents and purposes," or
"virtually," because Mr. Wallace does not expressly
maintain the abstract impossibility of laws and
causes other than those of utility and natural selec-
tion ; indeed, at the end of his treatise, he quotes
with approval Darwin's judgement, that "natural
selection has been the most important, but not the
exclusive means of modification." Nevertheless, as he
nowhere recognizes any other law or cause of adaptive
evolution^, he practically concludes that, on induc-
tive or empirical grounds, there is no such other law
or cause to be entertained — until we come to the par-
ticular case of the human mind. But even in making
this one particular exception — or in representing that
some other law than that of utility, and some other
cause than that of natural selection, must have been
concerned in evolving the mind of man — he is not
approximating his system to that of Darwin. On the
contrary, he is but increasing the divergence, for, of
course, it was Darwin's view that no such exception
could be legitimately drawn with respect to this
particular instance. And if, as I understand must
be the case, his expressed agreement with Darwin
touching natural selection not being the only cause
of adaptive evolution has reference to this point, the
quotation is singularly inapt.

Looking, then, to these serious differences between
his own doctrine of evolution — both organic and
mental — and that of Darwin, I cannot think that

* "The law of correlation," and the "laws of growth," he does
recognize; and shows that they furnish an explanation of the origin
of many characters, which cannot be brought under " the law of
utility."

22 Darwin, and after Darwin,

Mr. Wallace has chosen a suitable title for his book ;
because, in view of the points just mentioned, it is
unquestionable that Darwinism differs more widely
from the Origin of Species than does the Origin of
Species from the writings of the Neo-Lamarckians.
But, passing over this merely nominal matter, a few
words ought to be added on the very material
question regarding the human mind. In subsequent
chapters the more general question, or that which
relates to the range of utility and natural selection
elsewhere, will be fully considered.
Mr. Wallace says, —

" The immense interest that attaches to the origin of the
human race, and the amount of misconception which prevails
regarding the essential teachings of Darwin's theory on the
question, as well as regarding my own special views upon it,
induce me to devote a final chapter to its discussion.'*

Now I am not aware that there is any miscon-
ception in any quarter as to the essential teach-
ings of Darwin's theory on this question. Surely
it is rather the case that there is a very general and
very complete understanding on this point, both by
the friends and the foes of Darwin's theory — so much
so, indeed, that it is about the only point of similar
import in all Darwin's writings of which this can
be said. Mr. Wallace's ** special views " on the
other hand are, briefly stated, that certain features,
both of the morphology and the psychology of man,
are inexplicable by natural selection — or indeed by
any other cause of the kind ordinarily understood
by the term natural : they can be explained only
by supposing * the intervention of some distinct
individual intelligence," which, however, need not

Introduction. 23

necessarily be " one Supreme Intelligence," but some
other order of Personality standing anywhere in
" an infinite chasm between man and the Great Mind
of the universe ^" Let us consider separately the
corporeal and the mental peculiarities which are given
as justifying this important conclusion.

The bodily peculiarities are the feet, the hands, the
brain, the voice, and the naked skin.

As regards the feet Mr. Wallace writes, " It is
difficult to see why the prehensile power [of the great
toe] should have been taken away," because, although
*' it may not be compatible with perfectly easy erect
locomotion," " how can we conceive that early man,
as an animal, gained anything by purely erect
locomotion ^ ? " But surely it is not difficult to con-
ceive this. In the proportion that our simian
progenitors ceased to be arboreal in their habits (and
there may well have been very good utilitarian reasons
for such a change of habitat, analogous to those
which are known to have occurred in the phylogenesis
of countless pther animals), it would clearly have been
of advantage to them that their already semi-erect
attitude should have been rendered more and more
erect. To name one among several probabilities, the
more erect the attitude, and the more habitually it was
assumed, the more would the hands have been
liberated for all the important purposes of mani-
pulation. The principle of the physiological division
of labour would thus have come more and more into
play : natural selection would therefore have rendered
the upper extremities more and more suited to the

^ Natural Selection and Tropical NcUuf% p. 205 ; 1 891.

' Ibid. pp. 197-8.

24 DarwiUy and after Darwin.

execution of these purposes, while at the same time
it would have more and more adapted the lower ones
to discharging the sole function of locomotion. For
my own part, I cannot perceive any difficulty about
this : in fact, there is an admirable repetition of the
process in the ontogeny of our own children ^.

Next, with regard to the hand, Mr. Wallace says,
that it " contains latent capacities which are unused
by savages, and must have been even less used by
palaeolithic man and his still ruder predecessors."
Thus, " it has all the appearance of an organ prepared
for the use of civilized man 2." Even if this be true,
however, it would surely be a dangerous argument
to rely upon, seeing that we cannot say of how much
importance it may have been for early man — or even
apes — to have had their power of manipulation pro-
gressively improved. But is the statement true ? It
appears to me that if Mr. Wallace had endeavoured
to imitate the manufactures that were practised by
" palaeolithic man," he would have found the very
best of reasons for cancelling his statement. For it
is an extremely difficult thing to chip a flint into the
form of an arrow-head : when made, the suitable
attachment of it to a previously prepared arrow is no
easy matter : neither a bow nor a bow-string could
have been constructed by hands of much less per-
fection than our own i and the slaying of game with
the whole apparatus, when it has been constructed,
requires a manual dexterity which we may be per-

* For an excellent discussion on the ontogeny of the child in this
connexion, see Some Laws of Heredity, by Mr. S. S. Buckman, pp. 390,
et seq. (Proc. Coiteswold Nat. Field Club, vol. x. p. 3, 1892).

' loc. cit, p. 198.

Introduction. 25

fectly certain that Mr. Wallace — unless he has
practised the art from boyhood— does not possess.

So it is with his similar argument that the human
voice is more "powerful,*' more "flexible/' and pre-
sents a greater '' range " and " sweetness " than the
needs of savage life can be held to require. The futility
of this argument is self-evident as regards " power."
And although its weakness is not so obvious with
respect to the other three qualities which are named,
need we go further than the closely analogous case of
certain birds to show the precariousness of arguing
from such facts of organic nature to the special
operation of " a superior intelligence " ? I can hardly
suppose that Mr. Wallace will invoke any such
agency for the purpose of explaining the " latent
capacities " of the voice of a parrot. Yet, in many re-
spects, these are even more wonderful than those
of the human voice, albeit in a wild state they are
" never required or used V

Once more, with regard to the naked skin, it seems
sufficient to quote the following passage from the first
edition of the Descent of Man.

"The Rev. T. R. Stebbing, in commenting on this view,
remarks, that had Mr. Wallace ' employed his usual ingenuity
on the question of man's hairless skin, he might have seen
the possibility of its selection through its superior beauty,
or the health attaching to superior cleanliness. At any rate
it is surprising that he should picture to himself a superior

* For a discussion of this remarkable case, see Mental Evolution in
Animals, pp. 222-3. It appears to me that if Mr. Wallace's argument
from the "latent capacities of the voice of Man" is good for anything,
a fortiori it must be taken to prove that, in the case of the Parrot, " the
organ has been prepared in anticipation " of the amusement which the
cultivation of its latent capacities arous«» in " civilized man."

26 Darwin^ and after Darwin,

intelligence plucking the hair from the .backs of savage men
(to whom, according to his own account, it would have been use-
ful and beneficial), in order that the descendants of the poor
shorn wretches might, after many deaths irom cold and damp
in the course of many generations,' have been forced to raise
themselves in the scale of civilization through the practice of
various arts, in the manner indicated by Mr. \\ allace '."

To this it may be added that the Chimpanzee
"Sally" was largely denuded of hair, especially on
the back, or the part of " man's organization " on
which Mr. Wallace lays special stress, as being in this
respect out of analogy with other mammalia ^.

Lastly, touching his statement that the brain of
savage man is both quantitatively and qualitatively
in advance of his requirements, it is here also sufficient
to refer to Darwin's answer, as given in the Descent of
Man, Mr. Wallace, indeed, ignores this answer in his
recent re-publication of the argument ; but it is im-
possible to understand why he should have done so.
To me, at all events, it seems that one out of several
considerations which Darwin advances is alone
sufficient to show the futility of this argument.
I allude to the consideration that the power of
forming abstract ideas with the complex machinery
of language as the vehicle of their expression, is
probably of itself enough to account for both the
mass and the structure of a savage's brain. But this
leads us to the second division of Mr. Wallace's argu-

* Descent of Matty ist Ed. ch. xx. (Trans. Dev. Assoc, for Science, 1 890).

* The late Prof. Moseley informed me that, during his voyage on the
Challenger, he had seen many men whose backs were well covered with
hair. — For an excellent discussion of the whole question, chiefly in the
light of embryology, see the paper by Buckman already alluded to,
pp. 380-289. Also, for an account of an extraordinary hairy race of men,
see Alone with the Hairy Ainu, by A. H. Savage Landor, 1893.

Introduction. 2rj

ment, or that derived from the mental endowments
of mankind.

Here the peculiarities called into evidence are, " the
Mathematical Faculty," " the Artistic Faculties/' and
"the Moral Sense." With regard to the latter, he
avows himself a member of the intuitional school of
ethics ; but does not prove a very powerful advocate
as against the utilitarian \

It comes, then, to this. According to Mr. Wallace's

* E. g. " The special faculties we have been discussing clearly point to
the existence in man of something which he has not derived from
his animal progenitors — something which we may best refer to as
being of a spiritual essence or nature, capable of progressive de-
velopment under favourable conditions. On the hypothesis of this
spiritual nature, superadded to the animal nature of man, we are able
to understand much that is otherwise mysterious or unintelligible in
regard tb him, especially the enormous influence of ideas, principles,
and beliefs over his whole life and action. Thus alone can we understand
the constancy of the martyr, the unselfishness of the philanthropist,
the devotion of the patriot, the enthusiasm of the artist, and the resolute
and persevering search of the scientific worker after nature's secrets.
Thus we may perceive that the love of truth, the delight in beauty,
the passion for justice, and the thrill of exultation with which we
hear of any act of courageous self-sacrifice, are the workings within
us of a higher nature which has not been developed by means of the
struggle for material existence." {Darwinism^ p. 474.) I have quoted
this whole paragraph, because it is so inconsistent with the rest of
Mr, W allace's system that a mere epitome of it might well have been
suspected of error. Given an intellectual being, howsoever produced,
and what is there " mysterious or unintelligible " in ** the enormous
influence of ideas, principles, and beliefs over his whole life and
action"? Or again, if he be also a social being, what is the relevancy
of adducing " the constancy of the martyr," " the unselfishness of the
philanthropist," "the devotion of the patriot," "the love of truth,"
"the passion for justice,' "the thrill of exultation when we hear of any
act of courageous self-sacrifice," in evidence against the law of utility,
or in order to prove that a " nature " thus endowed has " not been
developed by means of the struggle for existence," when once this
struggle has been transferred from individuals to communities ? The
whole passage reads like an ironical satire in favour of " Darwinism,"
rather than a serious argument against it.

28 Darwin^ and after Darwin.

eventual conclusion, man is to be separated from the
rest of organic nature, and the steady progress of
evolution by natural causes is to be regarded as
stopped at its final stage, because the human mind
presents the faculties of mathematical calculation and
aesthetic perception. Surely, on antecedent grounds
alone, it must be apparent that there is here no kind
of proportion between the conclusion and the data from
which it is drawn. That we are not confined to
any such grounds, I will now try to show.

Let it be remembered, however, that in the following
brief criticism I am not concerned with the issue as
to whether, or how far, the " faculties" in question
have owed their origin or their development to
natural selectio7t. I am concerned only with the
doctrine that in order to account for such and such
particular " faculty " of the human mind, some order
of causation must be supposed other than what we
call natural. I am not a Neo-Darwinist, and so
have no desire to make " natural selection " synonym-
ous with '* natural causation" throughout the whole
domain of life and of mind. And I quite agree
with Mr. Wallace that, at any rate, the '• aesthetic
faculty " cannot conceivably have been produced by
natural selection — seeing that it is of no conceivable
life-serving value in any of the stages of its growth.
Moreover, it appears to me that the same thing has to
be said of the play instincts, sense of the ludicrous, and
sundry other " faculties " of mind among the lower
animals. It being thus understood that I am not
differing from Mr. Wallace where he imposes " hmits "
on the powers of natural .selection, but only where he
seems to take for granted that this is the same thing

Introduction, 2.^

as imposing limits on the powers of natural causation,
my criticism is as follows.

In the first place, it is a psychological fallacy to
regard the so-called " faculties " of mind as analogous
to " organs " of the body. To classify the latter with
reference to the functions which they severally perform
is to follow a natural method of classification. But
it is an artificial method which seeks to partition
mental faculty into this, that, and the other mental
faculties. Like all other purely artificial classifications,
this one has its practical uses ; but, also like
them, it is destitute of philosophical meaning. This
statement is so well recognized by psychologists, that
there is no occasion to justify it. But I must remark
that any cogency which Mr. Wallace's argument may
appear to present, arises from his not having recognized
the fact which the statement conveys. For, had he
considered the mind as a whole, instead of having
contemplated it under the artificial categories of
constituent " faculties," he would probably not have
laid any such special stress upon some of the latter.
In other words, he would have seen that the general
development of the human mind as a whole has
presumably involved the growth of those conven-
tionally abstracted parts, which he regards as really
separate endowments. Or, if he should find it easier
to retain the terms of his metaphor, we may answer
him by saying that the " faculties " of mind are
" correlated," like " organs " of the body ; and, there-
fore, that any general development of the various
other "faculties" have presumably entailed a collateral
development of the two in question.

Again, in the second place, it would seem that

30 Darwin^ and after Darwin,

Mr. Wallace has not sufficiently considered the co-
operation of other well-known natural causes, which
must have materially assisted the survival of the
fittest where these two " faculties " are concerned.
For, even if we disregard the inherited effects of
use — which, however, if entertained as possible in any
degree at all, must have here constituted an important
factor, — there remain on the one hand, the un-
questionable influences of individual education and,
on the other hand, of the selection principle operating
in the mind itself.

Taking these two points separately, it is surely
sufficiently well known that individual education —
or special training, whether of mind or body — usually
raises congenital powers of any kind to a more
or less considerable level above those of the normal
type. In other words, whatever doubt there may be
touching the inherited effects of use, there can be no
question touching the immense developmental effects
thereof in the individual life-time. Now, the conditions
of savage life are not such as lead to any deliberate
cultivation of the "faculties" either of the mathematical
or aesthetic order. Consequently, as might be ex-
pected, we find both of them in what Mr. Wallace
regards as but a " latent " stage of development. But
in just the same way do we find that the marvellous
powers of an acrobat when specially trained from child-
hood— say to curve his spine backwards until his teeth
can bite his heels — are " latent *' in all men. Or, more
correctly, they are potential in every child. So it is
with the prodigious muscular development of a trained
athlete, and with any number of other cases where
either the body or the mind is concerned. Why then

Introduction. 31

should Mr. Wallace select the particular instances of
the mathematical and aesthetic powers in savages as in
any special sense "prophetic" of future development
in trained members of civilized races ? Although it
is true that these "latent capacities and powers are
unused by savages," is it not equally true that savages
fail to use their latent capacities and powers as
tumblers and athletes? Moreover, is it not likewise
true that as used by savages, or as occurring normally
in man, such capacities and powers are no less poorly
developed than are those of the " faculties " on which
Mr. Wallace lays so much stress? In other words,
are not "latent capacities and powers" of all kinds
more or less equally in excess of anything that is ever
required of them by man in a state of nature ? There-
fore, if we say that where mathematics and the fine
arts are concerned the potential capacities of savage
man are in some mystical sense " prophetic " of
a Newton or a Beethoven, so in consistency ought we
to say that in these same capacities we discern a
similar prophecy of those other uses of civilized life
which we have in a rope-dancer or a clown.

Again, and in addition to this, it should be remem-
bered that, even if we do suppose any prophecy of
this kind where the particular capacities in question
are concerned, we must clearly extend the reference to
the lower animals. Not a few birds display aesthetic
feelings in a measure fairly comparable with those of
savages; while we know that some animals present
the germs of a " faculty " of computation ^ But. it is

^ See Proc. Zool. Soc, June 4, 1 889, for an account of the performances
in this respect of the Chimpanzee "Sally." Also, for some remarks on
the psychology of the subject, in Mental Evolution in Man, p. 315.
I should like to take this opportunity of stating that, after the two

32 Darwin^ and after Darwin,

needless to add, this fact is fatal to Mr. Wallace's
argument as I understand it — viz. that the " faculties "
in question have been in some special manner com-
municated by some superior intelligence to man.

Once more, it is obviously unfair to select such men as
a ** Newton, a La Place, a Gauss, or a Cayley *' for the
purpose of estimating the difference between savages
and civilized man in regard to the latter "faculty."
These men are the picked mathematicians of centuries.
Therefore they are men who not only enjoyed all
the highest possible benefits of individual culture, but
likewise those who have been most endowed with
mathematical power congenitally. So to speak, they
are the best variations in this particular direction
which our race is known to have produced. But
had such variations arisen among savages it is
sufficiently obvious that they could have come to
nothing. Therefore, it is the normal average of
" mathematical faculty " in civilized man that should
be contrasted with that of savage man ; and, when
due regard is paid to the all-important consideration
which immediately follows, I cannot feel that the
contrast presents any difficulty to the theory of human
evolution by natural causation.

Lastly, the consideration just alluded to is, that
civilized man enjoys an advantage over savage man
far in advance even of those which arise from a set-
tled state of society, incentives to intellectual training.
and so on. This inestimable advantage consists in
the art of writing, and the consequent transmission

publications above referred to, this animal's instruction was continued,
and that, before her death, her "counting" extended as far as ten.
That is to say, any number of straws asked for from one to ten would
always be correctly given.

Introduction. 33

of the effects of ailture from generation to generation*
Quite apart from any question as to the hereditary
transmission of acquired characters, we have in this
intellectual transmission of acquired experience a
means of accumulative cultivation quite beyond our
powers to estimate. For, unlike all other cases where
we recognize the great influence of individual use or
practice in augmenting congenital "faculties** (such
as in the athlete, pianist, &c.), in this case the effects of
special cultivation do not end with the individual life,
but are carried on and on through successive genera-
tions ad infinitum. Hence, a civilized man inherits
mentally, if not physically, the effects of culture for
ages past, and this in whatever direction he may choose
to profit therefrom. Moreover — and I deem this
an immensely important addition — in this unique
department of purely intellectual transmission, a
kind of non-physical natural selection is perpetually
engaged in producing the best results. For here
a struggle for existence is constantly taking place
among '■ ideas," " methods," and so forth, in what
may be termed a psychological environment. The
less fit are superseded by the more fit, and this not
only in th^ mind of the individual, but, through lan-
guage and literature, still more in the mind of the race.
"A Newton, a La Place, a Gauss, or a Cayley,"
would all alike have been impossible, but for a pre-
viously prolonged course of mental evolution due to the
selection principle operating in the region of mathe-
matics, by means of continuous survivals of the best
products in successive generations. And, of course,
the same remark applies to art in all its branches ^

* In Prof. Lloyd Morgan's Animal Life and Intelligence there is an
II. D

34 Darwifiy and after Darwin.

Quitting then the last, and in my opinion the
weakest chapter of Darwinism, the most important
points presented by other portions of this work are —
to quote its author's own enumeration of them — an
attempted *' proof that all specific characters are (or
once have been) either useful in themselves or corre-
lated with useful characters": an attempted "proof
that natural selection can, in certain cases, increase
the sterility of crosses": an attempted "proof that
the effects of use and disuse, even if inherited, must be
overpowered by natural selection " : an attempted
proof that the facts of variation in nature are in them-
selves sufficient to meet the difficulty which arises
against the theory of natural selection, as held by him,
from the swamping effects of free inter-crossing : and,
lastly, " a fuller discussion on the colour relations of
animals, with additional facts and arguments on the
origin of sexual differences of colour." As I intend to
deal with all these points hereafter, excepting the last,
it will be sufficient in this opening chapter to remark,
that in as far as I disagree with Mr. Wallace (and
agree with Darwin), on the subject of "sexual
differences of colour," my reasons for doing so have
been already sufficiently stated in Part I. But there
is much else in his treatment of this subject which
appears to me highly valuable, and therefore present-
ing an admirable contribution to the literature of
Darwinism. In particular, it appears to me that the
most important of his views in this connexion

admirable discussion on this subject, which has been published since the
above was written. The same has to be said of Weismann's Essay on
Music, where much that 1 have here said is anticipated. With the views
and arguments which Mr. Mivart has forcibly set forth I have already
dealt to the best of my ability in a work on Mental Evolution in Man.

Introduction. 35

probably represents the truth — namely, that, among
the higher animals, more or less conspicuous pecu-
liarities of colour have often been acquired for the
purpose of enabling members of the same species
quickly and certainly to recognize one another.
This theory was first published by Mr. J. E. Todd,
in 1888, and therefore but a short time before its
re-publication by Mr. Wallace. As his part in the
matter has not been sufficiently recognized, I should
like to conclude this introductory chapter by drawing
prominent attention to the merits of Mr. Todd's
paper. For not only has it the merit of priority, but
it deals with the whole subject of "recognition
colours" — or, as he calls them, "directive colours" —
in a more comprehensive manner than has been done
by any of his successors. In particular, he shows
that the principle of recognition-marking is not re-
stricted to facilitating sexual intercourse, but extends
also to several other matters of importance in the
economy of animal life^.

Having thus briefly sketched the doctrines of the
sundry Post-Darwinian Schools from a general point
of view, I shall endeavour throughout the rest of this
treatise to discuss in appropriate detail the questions
which have more specially come to the front in the
post-Darwinian period. It can scarcely be said that
any one of these questions has arisen altogether de
novo during this period ; for glimmerings, more or
less conspicuous, of all are to be met with in the
writings of Darwin himself. Nevertheless it is no
less true that only after his death have they been

' American Naturalist^ xxii. pp. 201-207.

D 2

36 Darwin^ and after Darwin.

lighted up to the full blaze of active discussion *. By
far the most important of them are those to which
the rest of this treatise will be confined. They are
four in number, and it is noteworthy that they are all
intimately connected with the great question which
Darwin spent the best years of his life in contem-
plating, and which has therefore, in one form or
another, occupied the whole of the present chapter—
the question as to whether natural selection has been
the sole cause, or but the chief cause of modification.

The four questions above alluded to appertain
respectively to Heredity, Utility, Isolation, and Physio-
logical Selection. Of these the first two will form
the subject-matter of the present volume, while the
last two will be dealt with in the final instalment of
Darwin, and after Darwin

* It is almost needless to say that besides the works mentioned in this
chapter, many others have been added to the literature of Darwinism
since Darwin's death. But as none of these profess to contain much
that is original, I have not thought it necessary to consider any of them
in this merely general review of the period in question. In subsequent
chapters, however, allusions will be made to those among them which
I deem of most importance.

[Since this note wns written and printed the following works have
been published to which it does not apply : Animal Life and Intelli-
gence, by Professor Lloyd Morgan ; The Colours of Animals, by
Professor Poulton ; and Materials for the Study of Variation, by
Mr. Bateson. All these works are of high value and importance.
Special reference should also be made to Professor Weismann's Essays.]

SECTION I

HEREDITY

CHAPTER 11.

Characters as Hereditary and Acquired
(Preliminary).

We will proceed to consider, throughout Section 1
of the present work, the most important among those
sundry questions which have come to the front
since the death of Darwin. For it was in the year
after this event that Weismann published the first
of his numerous essays on the subject of Heredity,
and, unquestionably, it has been these essays which
have given such prominence to this subject during
the last decade.

At the outset it is desirable to be clear upon
certain points touching the history of the subject;
the limits within which our discussion is to be con-
fined ; the relation in which the present essay stands
to the one that I published last year under the
title An Examination of Weismannism ; and several
other matters of a preliminary kind.

The problems presented by the phenomena of
heredity are manifold ; but chief among them is
the hitherto unanswered question as to the trans-
mission or non-transmission of acquired characters.
This is the question to which the present Section
will be confined.

Although it is usually supposed that this question

40 Darwin^ and after Darwin,

was first raised by Weismann, such was not the case.
Any attentive reader of the successive editions of
Darwin's works may perceive that at least from the
year 1859 he had the question clearly before his
mind ; and that during the rest of his life his
opinion with regard to it underwent considerable
modifications — becoming more and more Lamarckian
the longer that he pondered it. But it was not till
1875 that the question was clearly presented to
the general public by the independent thought of
Mr. Galton, who was led to challenge the Lamarckian
factors in toto by way of deduction from his
theory of Stirp — the close resemblance of which to
Professor Weismann's theory of Germ-plasm has
been shown in my Examination of Weismannism,
Lastly, I was myself led to doubt the Lamarck-
ian factors still further back in the seventies,
by having found a reason for questioning the main
evidence which Mr. Darwin had adduced in their
favour. This doubt was greatly strengthened on
reading, in the following year, Mr. Galton's Theory
of Heredity just alluded to ; and thereupon I com-
menced a prolonged course of experiments upon the
subject, the general nature of which will be stated
in future chapters. Presumably many other persons
must have entertained similar misgivings touching the
inheritance of acquired characters long before the
publication of Weismann's first essay upon the subject
in 1883. The question as to the inheritance of
acquired characters was therefore certainly not first
raised by Weismann— although, of course, there is
no doubt that it was conceived by him independently,
and that he had the great merit of calling general

Characters, Hereditary and Acquired, 41

attention to its existence and importance. On the
other hand, it cannot be said that he has succeeded in
doing very much towards its solution. It is for these
reasons that any attempt at dealing with Welsmann's
fundamental postulate — i.e. that of the non-inherit-
ance of acquired charactcrs^-was excluded from my
Examination of VVeismaniiism. As there stated he is
justified in assuming, for the purposes of his discussion,
a negative answer to the question of such inheritance ;
but evidently the question itself ought not to be in-
cluded within what we may properly understand by
" Weismannism." Weismannism, properly so called,
is an elaborate system of theories based on the funda-
mental postulate just mentioned — theories having
reference to the mechanism of heredity on the one hand,
and to the course of organic evolution on the other.
Now it was the object of the foregoing Examination to
deal with this system of theories per se ; and therefore
we have here to take a new point of departure and
to consider separately the question of fact as to the
inheritance or non-inheritance of acquired characters.
At first sight, no doubt, it will appear that in adopting
this method I am putting the cart before the horse.
For it may well appear that I ought first to have
dealt with the validity of Weismann's postulate, and
not till then to have considered the system of theories
which he has raised upon it. But this criticism is
not likely to be urged by any one who is well ac-
quainted with the questions at issue. For, in the first
place, it is notorious that the question of fact is
still open to question ; and therefore it ought to be
considered separately, or apart from any theories
which may have been formed with regard to it. In

42 Darwin, and after Darwin.

the second place, our judgement upon this question
of fact must be largely influenced by the validity of
general reasonings, such as those put forward in the
interests of rival theories of heredity ; and, as the
theory of germ-plasm has been so thoughtfully
elaborated by Professor Weismann, I have sought to
give it the attention which it deserves as preliminary
to our discussion of the question of fact which now lies
before us. Thirdly and lastly, even if this question
could be definitely answered by proving either that
acquired characters are inherited or that they are not,,
it would by no means follow that Weismann's theory
of heredity would be proved wholly false in the one
case, or wholly true in the other. That it need not
be wholly true, even were its fundamental postulate to
be proved so, is evident, because, although the fact
might be taken to prove the theory of Continuity, the
theory of Germ-plasm is, as above stated, very much
more than this. That the theory of Germ-plasm
need not be wholly false, even if acquired characters
should ever be proved heritable, a little thought may
easily show, because, in this event, the further question
would immediately arise as to the degrees and the
comparative frequency of such inheritance. For my
own part, as stated in the Examination, I have always
been disposed to accept Mr. Galton's theory of Stirp
in preference to that of Germ-plasm on this very
ground — i. e. that it does not dogmatically exclude the
possibility of an occasional inheritance of acquired
characters in faint though cumulative degrees. And
whatever our individual opinions may be touching the
admissibility of such a via media between the theories
of Pangenesis and Germ-plasm, at least we may all

Characters^ Hereditary and Acquired, 43

agree on the desirability of fully considering the
matter as a preliminary to the discussion of the
question of fact

As it is not to be expected that even those who
may have read my previous essay can now carry all
these points in their memories, I will here re-state
them in a somewhat fuller form.

The following diagram will serve to give a clearer
view of the sundry parts of Professor Weismann's
system of theories, as well as of their relations to one
another.

\

/y

*/-■»"

\\%

f7/

V

1

1

1

6

s

•s

8

>,

§

1

'€

.9

1

§

Postulate as to the absolute non-inheritance of acquired characters.

Now, as just explained, the parts of this system
which may be properly and distinctively called
'• Weismannism " are those which go to form the
Y-like structure of deductions from the fundamental
postulate. Therefore, it was the Y-like system of

44 Darwin, and after Darwin,

deductions which were dealt with in the Exammation
of Weis7nannisrn^ while it is only his basal postulate
which has to be dealt with in the following chapters.

So much, then, for the relations of Weismann's
system of theories to one another. It is, however, of
even more importance that we should gain a clear
view of the relations between his theory of heredity
to those of Darwin and of Galton, as preliminary to
considering the fundamental question of fact.

As we have already seen, the theory of germ-plasm
is not only a theory of heredity : it is also, and more
distinctively, a theory of evolution, &c. As a theory
of heredity it is grounded on its author's fundamental
postulate — the continuity of germ -plasm. But as a
theory of evolution, it requires for its support this
additional postulate, that the continuity of germ-
plasm has been absolute "since the first origin of
life." It is clear that this additional postulate is not
needed for his theory of heredity, but only for his
additional theory of evolution, &c. There have been
one or two other theories of heredity, prior to this one,
which, like it, have been founded on the postulate of
Continuity of the substance of heredity ; but it has
not been needful for any of these theories to postulate
further that this substance has been always thus
isolated, or even that it is now invariably so. For
even though the isolation be frequently invaded by
influences of body-changes on the congenital characters
of this substance, it does not follow that this principle
of Continuity may not still be true in the main, even
although it is supplemented in some degree by that
of use-inheritance. Indeed, so far as the pheno
mena of heredity are concerned, it is conceivable that

Characters^ Hereditary and Acquired, 45

all congenital characters were originally acquired,
and afterwards became congenital on account of their
long inheritance. I do not myself advocate this view
as biologically probable, but merely state it as logically
possible, and in order to show that, so far as the
phenomena of heredity are concerned, there appears
to be no reason for Weismann's deduction that the
principle of Continuity, if true at all, must be absolute.
And it would further appear, the only reason why he
makes this deduction (stem of the Y) is in order to
provide a foundation for his further theories of evolu-
tion, &c. (arms of the Y). It is indeed necessary for
these further theories that body-changes should
never exercise any hereditary influence on the heredi-
tary endowments of germ-plasm, and therefore it is
that he posits the substance of heredity as, not only
continuous, but uninterruptably so "since the first
origin of life."

Now, this may be made more clear by briefly com-
paring Weismann's theory with those of Darwin and
of Galton. Weismann's theory of heredity, then,
agrees with its predecessors which we are considering
in all the following respects. The substance of heredity
is particulate ; is mainly lodged in highly specialized
cells ; is nevertheless also distributed thoughout the
general cellular tissues, where it is concerned in all
processes of regeneration, repair, and a-sexual repro-
duction ; presents an enormously complex structure,
in that every constituent part of a potentially future
organism is represented in a fertilized ovum by cor-
responding particles; is everywhere capable of virtually
unlimited multiplication, without ever losing its here-
ditary endowments ; is often capable of carrying

46 Darwin^ and after Darwin,

these endowments in a dormant state through a long
series of generations until at last they re-appear
in what we recognize as recursions. Thus far all
three theories are in agreement. In fact, the only
matter of any great importance wherein they disagree
has reference to the doctrine of Continuity ^ For
while Darwin's theory supposes the substance of
heredity to be mainly formed anew in each ontogeny,
and therefore that the continuity of this substance is
for the most part interrupted in every generation ^,
Weismann's theory supposes this substance to be
formed only during the phylogeny of each species,
and therefore to have been absolutely uninterrupted
since the first origin of life.

But now, Galton's theory of heredity stands much
nearer to Weismann's in this matter of Continuity ;
for it is, as he says, a theory of " modified pangenesis,"
and the modification consists in allowing very much
more for the principle of Continuity than is allowed
by Darwin's theory ; in fact he expresses himself as
quite willing to adopt (on adequate grounds being
shown) the doctrine of Continuity as absolute, and
therefore propounded, as logically possible, the iden-
tical theory which was afterwards and independently
announced by Weismann. Or, to quote his own
words —

" We might almost reserve our belief that the structural [i. e.
somatic] cells can react on the sexual elements at all, and we

* Originally, Weismann's further assumption as to the perpetual
stability of germ-plasm, " since the first origin of sexual reproduction,"
was another very important point of difference, but this has now been
withdrawn.

* 1 say '' mainly formed anew," and "for the most part interrupted,"
because even Darwin's theory does not, as is generally supposed, exclude
the doctrine of Continuity in toto.

Characters^ Hereditary and Acquired. 47

may be confident that at most they do so in a very faint degree;
in other words, that acquired modifications are barely, if at all,
inherited^ in the correct sense of that word *."

So far Mr. Galton ; but for Weismann's further
theory of evolution, &c., it is necessary to postulate
the additional doctrine in question ; and it makes
a literally immeasurable difference to any theory of
evolution whether or not we entertain this additional
postulate. For no matter how faintly or how fitfully
the substance of heredity may be modified by somatic
tissues, the Lamarckian principles are hypothetically
allowed some degree of play. And although this is
a lower degree than Darwin supposed, their influence
in determining the course of organic evolution may
still have been enormous : seeing that their action in
any degree must always have been directive of varia-
tion on the one hand, and cumulative on the other.

Thus, by merely laying this theory side by side
with Weismann's we can perceive at a glance how
a pure theory of heredity admits of being based
on the postulate of Continuity alone, without cum-
bering itself by any further postulate as to this
Continuity being absolute. And this, in my opinion
is the truly scientific attitude of mind for us to adopt
as preliminary to the following investigation. For
the whole investigation will be concerned —and con-
cerned only — with this question of Continuity as ab-
solute, or as admitting of degrees. There is, without
any question, abundant evidence to prove that the
substance of heredity is at least partly continuous
(Gemmules). It may be that there is also abundant
evidence to prove this substance much more largely

* Theory of Heredity (Joum. Anthrop. Inst. 1875, p. 346).

48 Darwin^ and after Darwin,

continuous than Darwin supposed (Stirp) ; but be this
as it may, it is certain that any such question as to
the degree of continuity differs, toto caelo, from that as
to whether there can ever be any continuity at all.

How, then, we may well ask, is it that so able
a naturalist and so clear a thinker as Weismann
can have so far departed from the inductive methods
as to have not merely propounded the question
touching Continuity and its degrees, or even of Con-
tinuity as absolute ; but to have straightway assumed
the latter possibility as a basis on which to run
a system of branching and ever-changing speculations
concerning evolution, variation, the ultimate struc-
ture of living material, the intimate mechanism of
heredity, or, in short, such a system of deductive
conjectures as has never been approached in the
history of science? The answer to this question is
surely not far to seek. Must it not be the answer
already given? Must it not have been for the sake
of rearing this enormous structure of speculation
that Weismann has adopted the assumption of
Continuity as absolute? As we have just seen,
Galton had well shown how a theory of heredity
could be founded on the general doctrine of Con-
tinuity, without anywhere departing from the in-
ductive methods — even while fully recognizing the
possibility of such continuity as absolute. But
Galton's theory was a " Theory of Heredityl^ and
nothing more. Therefore, while clearly perceiving
that the Continuity in question may be absolute,
he saw no reason, either in fact or in theory, for
concluding that it must be. On the contrary, he
saw that this question is, for the present, necessaril)'

Characters^ Hereditary and Acquired. 49

unripe for profitable discussion — and, a fortioriy for
the shedding of clouds of seed in all the directions
of ** Weismannism."

Hence, what I desire to be borne in mind through-
out the following discussion is, that it will have
exclusive reference to the question of fact already-
stated, without regard to any superjacent theories ;
and, still more, that there is a vast distinction
between any question touching the degrees in which
acquired characters are transmitted to progeny, and
the question as to whether they are ever trans-
mitted in any degree at all. Now, the latter question,
being of much greater importance than the former,
is the one which will mainly occupy our attention
throughout the rest of this Section.

We have already seen that before the subject was
taken up by Weismann the difference between acquired
and congenital characters in respect to transmissibility
was generally taken to be one of degree ; not one of
kind. It was usually supposed that acquired char-
acters, although not so fully and not so certainly
inherited as congenital characters, nevertheless were
inherited in some lesser degree ; so that if the same
acquired character continued to be successively ac-
quired in a number of sequent generations, what was
at first only a slight tendency to be inherited would
become by summation a more and more pronounced
tendency, till eventually the acquired character might
become as strongly inherited as a congenital one.
Or, more precisely, it was supposed that an acquired
character, in virtue of such a summation of hereditary
influence, would in time become congenital. Now,
if this supposition be true, it is evident that more or

II. E

50 Darwin, and after Darwin,

less assistance must be lent to natural selection in
its work of evolving adaptive modifications ^ And
inasmuch as we know to what a wonderful extent
adaptive modifications are secured during individual
life-times — by the direct action of the environment on
the one hand, and by increased or diminished use of
special organs and mental faculties on the other — it
becomes obvious of what importance even a small
measure of transmissibility on their part would be
in furnishing to natural selection ready-made varia-
tions in required directions, as distinguished from
promiscuous variations in all directions. Contrari-
wise, if functionally-produced adaptations and adapta-
tions produced by the direct action of the environ-
ment are never transmitted in any degree, not only

* Mr. Piatt Ball has, indeed, argued that " use- inheritance would often
be an evil," since, for example, "the condyle of the human jaw would
become larger than the body of the jaw, because as the fulcrum of the
lever it receives more pressure"; and similarly as reg;^rds many other
hypothetical cases which he mentions. ( The Effects of Use and Disuse,
pp. 1 28-9 et seq.) But it is evident that this argument proves too much.
For if the effects of use and disuse as transmitted to progeny would be
an evil, it could only be because these effects as they occur in the parents
are an evil— and this they most certainly are not, being, on the contrary
and as a general rule, of a high order of adaptive value. Moreover, in the
race, there is a superadded agency always at work, which must effect-
ually prevent any undue accumulation of these effects — namely, natural
selection, which every Darwinist accepts as a controlling principle of all
or any other principles of change. Therefore, if, as first produced in
the life-time of individuals, the effects of use and disuse are not injurious,
much less can they become so if transmitted through the life-time of
species. Again, Mr. Wallace argues that, even supposing use-inheritance
to occur, its adapting work in the individual can never extend to the
race, seeing that the natural selection of fortuitous variations in the
directions required must always produce the adaptations more quickly
than would be possible by use-inheritance. This argument, being one
of more weight, will be dealt with in a future chapter.

Characters, Hereditary and Acquired, 51

would there be an incalculable waste, so to speak, of
adaptive modifications— these being all laboriously
and often most delicately built up during life-times of
individuals only to be thrown down again as regards
the interest of species — but so large an additional
burden would be thrown upon the shoulders of natural
selection that it becomes difificult to conceive how
even this gigantic principle could sustain it, as I shall
endeavour to show more fully in future chapters. On
the other hand, however, Weismann and his followers
not only feel no difficulty in throwing overboard all
this ready-made machinery for turning out adaptive
modifications when and as required ; but they even
represent that by so doing they are following the
logical maxim, Entia non sunt multiplicanda praeter
necessitatem — which means, in its relation to causality,
that we must not needlessly multiply hypothetical
principles to explain given results. But when appeal
is here made to this logical principle — the so-called
Law of Parsimony — two things are forgotten.

In the first place, it is forgotten that the very
question in debate is whether causes of the Lamarck-
ian order are unnecessary to explain all the phe-
nomena of organic nature. Of course if it could be
proved that the theory of natural selection alone
is competent to explain all these phenomena, appeal
to the logical principle in question would be justi-
fiable. But this is precisely the point which the
followers of Darwin refuse to accept ; and so long as
it remains the very point at issue, it is a mere begging
the question to represent that a class of causes which
have hitherto been regarded as necessary are, in
fact, unnecessary. Or, in other words, when Darwin

E 2

52 Darwin, and after Darwin.

himself so decidedly held that these causes are neces-
sary as supplements to natural selection, the burden
of proof is quite as much on the side of Weismann
and his followers to show that Darwin's opinion
was wrong, as it is on the side of Darwin's followers
to show that it was right. Yet, notwithstanding the
elaborate structure of theory which Weismann has
raised, there is nowhere one single fact or one single
consideration of much importance to the question
in debate which was not perfectly well known to
Darwin. Therefore I say that all this challenging
of Darwinists to justify their " Lamarckian assump-
tions" really amounts to nothing more than a pitting
of opinion against opinion, where there is at least as
much call for justification on the one side as on the
other.

Again, when these challenges are thrown down by
Weismann and his followers, it appears to be forgotten
that the conditions of their own theory are such as
to render acceptance of the gauge a matter of great
difficulty. The case is very much like that of a
doughty knight pitching his glove into the sea, and
then defying any antagonist to take it up. That this
is the case a very little explanation will suffice to
show.

The question to be settled is whether acquired
characters are ever transmitted by heredity. Now
suppose, for the sake of argument, that acquired
characters are transmitted by heredity — though not so
fully and not so certainly as congenital characters —
how is this fact to be proved to the satisfaction of
Weismann and his followers? First of all they
answer, — Assuredly by adducing experimental proof

Characters, Hereditary and Acquired, 53

of the inheritance of injuries, or mutilations. But
in making this answer they appear to forget that
Darwin has already shown its inefficiency. That the
self-styled Neo-Lamarckians have been much more
unguarded in this respect. I fully admit ; but it is
obviously unfair to identify Darwin's views with those
of a small section of evolutionists, who are really as
much opposed to Darwin's teaching on one side as is
the school of Weismann on the other. Yet, on read-
ing the essays of Weismann himself — and still more
those of his followers— one would almost be led to
gather that it is claimed by him to have enunciated
the distinction between congenital and acquired char-
acters in respect of transmissibility ; and therefore
also to have first raised the objection which lies
against the theory of Pangenesis in respect of the
non-transmissibility of mutilations. In point of fact,
however, Darwin is as clear and decided on these
points as Weismann. And his answer to the obvious
difficulty touching the non-transmissibility of mutila-
tions is, to quote his own words, '* the long-confinued
inheritance of a part which has been removed during
many generations is no real anomaly, for gem mules
formerly derived from the part are multiplied and
transmitted from generation to generation ^" There-
fore, so far as Darwin's theory is concerned, the
challenge to produce evidence of the transmission of
injuries is irrelevant : it is no more a part of Darwin's
theory than it is of Weismann's to maintain that
injuries are transmitted.

There is, however, one point in this connexion to
which allusion must here be made. Although Darwin

' Variation under Domestication, ii. 392.

54 Darwifiy and after Darwin.

did not believe in the transmissibility of mutilations
when these consist merely in the amputation of parts
of an organism, he did believe in a probable tendency
to transmission when removal of the part is followed
by gangrene. For, as he says, in that case all the
gemmules of the mutilated or amputated part, as they
are gradually attracted to that part (in accordance
with the law of affinity which the theory assumes),
will be successively destroyed by the morbid process.
Now it is of importance to note that Darwin made
this exception to the general rule of the non-trans-
missibility of mutilations, not because his theory of
pangenesis required it, but because there appeared to
be certain very definite observations and experiments
— which will be mentioned later on — proving that
when mutilations are followed by gangrene they are
apt to be inherited : his object, therefore, was to
reconcile these alleged facts with his theory, quite as
much as to sustain his theory by such facts.

So much, then, for the challenge to produce
direA evidence of the transmissibility of acquired
characters, so far as mutilations are concerned :
believers in Darwin's theory, as distinguished from
Weismann's, are under no obligation to take up such
a challenge. But the challenge does not end here.
Show us, say the school of Weismann, a single in-
stance where an acquired character of any kind (be it
a mutilation or otherwise) has been inherited : this is
all that we require : this is all that we wait for : and
surely, unless it be acknowledged that the Lamarckian
doctrine reposes on mere assumption, at least one
such case ought to be forthcoming. Well, nothing
can sound more reasonable than this in the first in-

Characters, Hereditary and Acquired. 55

stance ; but as soon as we begin to cast about for
cases which will satisfy the Neo-Darwinians, we find
that the structure of their theory is such as to pre-
clude, in almost every conceivable instance, the possi-
bility of meeting their demand. For their theory begins
by assuming that natural selection is the one and only
cause of organic evolution. Consequently, what their
demand amounts to is throwing upon the other side
the burden of disproving this assumption — or, in other
words, of proving the negative that in any given case of
transmitted adaptation natural selection has not been
the sole agent at work. Now, it must obviously be
in almost all cases impossible to prove this negative
among species in a state of nature. For, even sup-
posing that among such species Lamarckian prin-
ciples have had a large share in the formation of
hereditary and adaptive characters, how would Weis-
mann himself propose that we should set about the
proof of such a fact, where the proof demanded by his
assumption is, that the abstract possibility of natural
selection having had anything to do with the matter
must be excluded.? Obviously this is impossible in
the case of inherited characters which are also
adaptive characters. How then does it fare with the
case of inherited characters which are not also
adaptive ? Merely that this case is met by another
and sequent assumption, which constitutes an integral
part of the Neo-Darwinian creed — namely, that in
nature there can be no such characters. Seeing that
natural selection is taken to be the only possible
cause of change in species, it follows that all changes
occurring in species must necessarily be adaptive,
whether or not we are able to perceive the adaptations.

56 Darwin, and after Darwin.

In this way apparently useless characters, as well as
obviously useful ones, are ruled out of the question :
that is to say, all hereditary characters of species in
a state of nature are assumed to be due to natural
selection, and then it is demanded that the validity of
this assumption should be disproved by anybody who
doubts it. Yet Weismann himself would be unable
to suggest any conceivable method by which it can
be disproved among species in a state of nature — and
this even supposing that the assumption is entirely
false \

Consequently, the only way in which these
speciously-sounding challenges can be adequately met
is by removing some individuals of a species from
a state of nature, and so from all known influences
of natural selection ; then, while carefully avoiding
artificial selection, causing these individuals and their
progeny through many generations unduly to exer-
cise some parts of their bodies, or unduly to fail in
the exercise of others. But, clearly, such an experi-
ment is one that must take years to perform, and
therefore it is now too early in the day to reproach
the followers of Darwin with not having met the
challenges which are thrown down by the followers
of Weismann ^,

^ In subsequent chapters, especially devoted to the question (i.e.
Section II), the validity of this assumption will be considered on
its own merits.

* I say '* the followers of Weismann," because Weismann himself, with
his clear perception of the requirementsof experimental research, expressly
states the above considerations, with the conclusions to which they
lead. Nevertheless, he is not consistent in his utterances upon this
matter; for he frequently expresses himself to the effect, " that the onus
probandi rests with my opponents, and therefore they ought to bring
forward actual proofs " {Essays, i. p. 390). But, as above shown, the

Characters^ Hereditary and Acquired. 57

Probably enough has now been said to show that
the Neo- Darwinian assumption precludes the possi-
bility of its own disproof from any of the facts of
nature (as distinguished from domestication)— and
this even supposing that the assumption be false. On
the other hand, of course, it equally precludes the
possibility of its own proof; and therefore it is as
idle in Darwinists to challenge Weismann for proof of
his negative (i.e. that acquired characters are not trans-
mitted), as it is in Weismann to challenge Darwinists
for proof of the opposite negative (i. e. that all
seeming cases of such transmission are not due to
natural selection). This dead-lock arises from the
fadt that in nature it is beyond the power of the
followers of Darwin to exclude the abstract possi-
bility of natural selection in any given case, while it is
equally beyond the power of the followers of Weismann
to exclude the abstract possibility of Lamarckian
principles. Therefore at present the question must
remain for the most part a matter of opinion, based
upon general reasoning as distinguished from special
facts or crucial experiments. The evidence available
on either side is presumptive, not demonstrative^.
But it is to be hoped that in the future, when time
shall have been allowed for the performance of definite
experiments on a number of generations of domesti-
cated plants or animals, intentionally shielded from
the influences of natural selection while exposed to
those of the Lamarckian principles, results will be

onus rests as much with him as with his opponents ; while, even if
his opponents are light, he elsewhere recognizes that they can bring
"actual proofs" of the fact only as a result of experiments which
must take many years to perform.
1 Note A.

58 DarwiUy and after Darwin.

gained which will finally settle the question one
way or the other.

Meanwhile, however, we must be content with the
evidence as it stands ; and this will lead us to the
second division of our subject. That is to say, having
now dealt with the antecedent, or merely logical,
state of the question, we have next to consider what
actual, or biological, evidence there is at present
available on either side of it. Thus far, neither side
in the debate has any advantage over the other. On
grounds of general reasoning alone they both have
to rely on more or less dogmatic assumptions. For
it is equally an unreasoned statement of opinion
whether we allege that all the phenomena of organic
evolution can be, or can not be, explained by the
theory of natural selection alone. We are at present
much too ignorant touching the causes of organic
evolution to indulge in dogmatism of this kind ;
and if the question is to be referred for its answer
to authority, it would appear that, both in respect
of number and weight, opinions on the side of having
provisionally to retain the Lamarckian factors are
more authoritative than those per contra ^.

Turning then to the question of fact, with which
the following chapters are concerned, I will conclude
this preliminary one with a few words on the method
of discussion to be adopted.

First I will give the evidence in favour of Lamarck-
ianism ; this will occupy the next two chapters.

* For a fair and careful statement of the present balance of authoritative
opinion upon the question, see H. F. Osborn, Anurican NatureUist^
189a, pp. 537-^7.

Characters f Hereditary and Acquired. 59

Then, in Chapter V, I will similarly give the evidence
per contra, or in favour of Continuity as absolute.
Lastly, I will sum up the evidence on both sides,
and give my own judgement on the whole case. But
on whichever side I am thus acting as special pleader
for the time being, I will adduce only such arguments
as seem to me valid — excluding alike from both the
many irrelevant or otherwise invalid reasonings which
have been but too abundantly published. Moreover,
I think it will be convenient to consider all that has
been said — or may be said — in the way of criticism
to each argument by the opposite side while such
argument is under discussion — i. e. not to wait till
all the special pleading on one side shall have been
exhausted before considering the exceptions which
have been (or admit of being) taken to the arguments
adduced, but to deal with such exceptions at the time
when each of these arguments shall have been severally
stated. Again, and lastly, I will arrange the evidence
in each case — i.e. on both sides — under three
headings, viz. (A) Indirect, (B) Direct, and (C) Ex-
perimental \

* [The above paragraph is allowed to remain exactly as Mr. Romanes
left it. Chapters V and VI were however not completed. See note
appended to Preface. C. LI. M.]

CHAPTER III.

Characters as Hereditary and Acquired
(cotttmued).

(A.)

Indirect Evidence in favour of the Inheritance
of Acquired Characters.

Starting with the evidence in favour of the so-
called Lamarckian factors, we have to begin with the
Indirect — and this without any special reference to
the theories, either of Weismann or of others.

It has already been shown, while setting forth in
the preceding chapter the antecedent standing of the
issue, that in this respect the prima facie presump-
tion is wholly on the side of the transmission, in
greater degree or less, of acquired characters. Even
Weismann allows that all " appearances " point in
this direction, while there is no inductive evidence
of the action of natural selection in any one case,
either as regards germs or somas, and therefore,
a fortiori, of the "all-sufficiency" of this caused It
is true that in some of his earlier essays he has
argued that there is no small weight of prima facie
evidence in favour of his own views as to the non-

^ See, especially, his excellent remarks on this point, Contemp. Rev
Sept. 1893.

Characters y Hereditary and Acquired, 6i

inheritance of acquired characters. This, however,
will have to be considered in its proper place further
on. Meanwhile I shall say merely in general terms
that it arises almost entirely from a confusion of
the doctrine of Continuity as absolute with that of
Continuity as partial, and therefore as admitting of
degrees in different cases — which, as already ex-
plained, are doctrines wide as the poles asunder.
But, leaving aside for the present such prima facie
evidence as Weismann has adduced on his side
of the issue, I may quote him as a hostile witness
to the weight of this kind of evidence per contra^
in so far as it has already been presented in the
foregoing chapter. Indeed, Weismann is much too
logical a thinker not to perceive the cogency of
the '^ appearances " which lie against his view of
Continuity as absolute — although he has not been
sufficiently careful in distinguishing between such
Continuity and that which admits of degrees.

We may take it, then, as agreed on all hands that
whatever weight merely prima facie evidence may in
this matter be entitled to, is on the side of what
I have termed moderated Lamarckianism : first sight
" appearances '' are against the Neo-Darwinian doc-
trine of the absolute non- inheritance of acquired
characters.

Let us now turn to another and much more
important line of mdirect evidence in favour of
moderated Lamarckianism.

The difficulty of excluding the possibility of na-
tural selection having been at work in the case of
wild plants and animals has already been noticed.

62 Darwin^ and after Darwin.

Therefore we may now appreciate the importance
of all facts or arguments which attenuate the prob-
ability of natural selection having been at work.
This may be done by searching for cases in nature
where a congenital structure, although unquestionably
adaptive, nevertheless presents so small an amoum
of adaptation, that we can scarcely suppose it to
have been arrived at by natural selection in the
struggle for existence, as distinguished from the
inheritance of functionally-produced modifications.
For if functionally-produced modifications are ever
transmitted at all, there is no limit to the minute-
ness of adaptive values which may thus become
congenital ; whereas, in order that any adaptive
structure or instinct should be seized upon and ac-
cumulated by natural selection, it must from the
very first have had an adaptive value suflficiently
great to have constituted its presence a matter of
life and death in the struggle for existence. Such
structures or instincts must not only have always
presented some measure of adaptive value, but
this must always have 'been sufficiently great to
reach what I have elsewhere called a selection-
value. Hence, if we meet with cases in nature where
adaptive structures or instincts present so low a
degree of adaptive value that it is difficult to con-
ceive how they could ever have exercised any
appreciable influence in the battle for life, such cases
may fairly be adduced in favour of the Lamarckian
theory. For example, the Neo- Lamarckian school of
the United States is chiefly composed of palaeon-
tologists ; and the reason of this seems to be that
the study of fossil forms — or of species in process of

Characters^ Hereditary and Acquired. 63

r „....,„

^H which in their nascent condition present such ex-
ceedingly minute degrees of adaptive value, that it
seems unreasonable to attribute their development to
a survival of the fittest in the complex struggle for
existence. But as this argument is in my opinion
of greatest force when it is applied to certain facts
of physiology with which I am about to deal, I will
not occupy space by considering any of the number-
less cases to which the Neo-Lamarckians apply it
within the region of palaeontology ^

Turning then to inherited actions, it is here that
we might antecedently expect to find our best evi-
dence of the Lamarckian principles, if these principles
have really had any share in the process of adaptive
evolution. For we know that in the life-time of
individuals it is action, and the cessation of action,
which produce nearly all the phenomena of acquired
adaptation —use and disuse in animals being merely
other names for action and the cessation of action.
Again, we know that it is where neuro- muscular
machinery is concerned that we meet with the most
conclusive evidence of the remarkable extent to
which action is capable of co-ordinating structures
for the ready performance of particular functions ;
so that even during the years of childhood *• practice
makes perfect " to the extent of organizing neuro-
muscular adjustments, so elaborate and complete as
to be indistinguishable from those which in natural

* There is now an extensive literature within this region. Theprincipal
writers are Cope, Scott and Osborn. Unfortunately, however, the
facts adduced are not crucial as test-cases between the rival theories —
nearly all of them, in fact, being equally susceptible of explanation by
either.

64 Darwin y and after Darwin,

species we recognized as reflex actions on the one
hand, and instinctive actions on the other. Hence,
if there be any such thing as " use-inheritance ' at
all, it is in the domain of reflex actions and instinc-
tive actions that we may expect to find our best
evidence of the fact. Therefore I will restrict the
present line of evidence — (A) — to these two classes
of phenomena, as together yielding the best evidence
obtainable within this line of argument.

The evidence in favour of the Lamarckian factors
which may be derived from the phenomena of reflex
action has never, I believe, been pointed out before ;
but it appears to me of a more cogent nature than
perhaps any other. In order to do it justice, I will
begin by re-stating an argument in favour of these
factors which has already been adduced by previous
writers, and discussed by myself in published corre-
spondence with several leaders of the ultra- Darwinian
school.

Long ago Professor Broca and Mr. Herbert Spencer
pointed to the facts of co-adaptation, or co-ordination
within the limits of the same organism, as presenting
good evidence of Lamarckian principles, working in
association with natural selection. Thus, taking one
of Lamarck's own illustrations, Mr. Spencer argued
that there must be numberless changes — extending to
all the organs, and even to all the tissues, of the
animal — which in the course of many generations
have conspired to convert an antelope into a giraffe.
Now the point is, that throughout the entire history
of these changes their utility must always have been
dependent on their association. It would be useless

Character Sy Hereditary and Acquired, 65

that an incipient giraffe should present the peculiar
form of the hind-quarters which we now perceive,
unless at the same time it presented the correspond-
ingly peculiar form of the fore-quarters ; and as each
of these great modifications entails innumerable sub-
ordinate modifications throughout both halves of the
creature concerned, the chances must have been in-
finitely great against the required association of so man)
changes happening to have arisen congenitally in the
same individuals by way of merely fortuitous variation.
Yet, if we exclude the Lamarckian interpretation,
which gives an intelligible cause of co-ordination
we are required to suppose that such a happy con-
currence of innumerable independent variations must
have occurred by mere accident — and this on innu-
merable different occasions in the bodies of as many
successive ancestors of the existing species. For at
each successive stage of the improvement natural
selection (if working alone) must have needed all, or
at any rale most, of the co-ordinated parts to occur in
the same individual organisms ^

In alluding to what I have already published upon
the difficulty which thus appears to be presented to
his theory, Weismann says, "At no distant time I hope
to be able to consider this objection, and to show that
the apparent support given to the old idea [i. e. of the
transmission of functionally-produced modifications]
is really insecure, and breaks down as soon as it is
critically examined ^.*'

* For another and better illustration more recently published by
Mr. Spencer, see The Inadequacy of Natural Selection, p. 32.

* Essays on Heredity, vol. i, p. 389.

[For further treatment of the subject under discussion see Weismann,
The All-sufficiency of Natural Selection (Contemp. Rev. Sept. and

II. F

66 Darwin^ and after Darwin.

So much for what Weismann has said touching this
matter. But the matter has also been dealt with both
by Darwin and by Wallace. Darwin very properly
distinguishes between the fallacy that '* with animals
such as the girafi'e, of which the whole structure is
admirably co-ordinated for certain purposes, it has
been supposed that all the parts must have been
simultaneously modified^," and the sound argument
that the co-ordination itself cannot have been due to
natural selection alone. This important distinction
may be rendered more clear as follows.

The facts of artificial selection prove that immense
modifications of structure may be caused by a cumu-
lative blending in the same individuals of characters
which were originally distributed among different
individuals. Now, in the parallel case of natural
selection the characters thus blended will usually —
if not invariably — be of an adaptive kind ; and their
eventual blending together in the same individuals
will be due to free intercrossing of the most fit.
But this blending of adaptations is quite a different
matter from the occurrence of co-ordination. For
it belongs to the essence of co-ordination that each
of the co-ordinated parts should be destitute of adap-
tive value per se : the adaptation only begins to arise
if all the parts in question occur associated together in
the same individuals from the very first. In this
case it is obvious that the analogy of artificial selec-
tion can be of no avail in explaining the facts,
since the difficulty presented has nothing to do with

Oct. 1893), and The Effect of External Influences upon Development.
•* Romanes Lecture " 1894, and Spencer, Weismannism once more i^Cont.
Rev. Oct. 1894). C. LI. M.]
^ Variation^ &c., vol. ii. p. 206.

Characters^ Hereditary and Acquired. 67

the blending in single individuals of adaptations
previously distributed among different individuals .
it has to do with the simultaneous appearance in
single individuals of a co-adaptation of parts, none
of which could ever have been of any adaptive
value had it been previously distributed among
different individuals. Consequently, where Darwin
comes to consider this particular case (or the case
of co-adaptation as distinguished from the blending
of adaptations), he freely invokes the aid of the
Lamarckian principles \

Wallace, on the other hand, refuses to do this, and
says that " the best answer to the difficulty" of sup-
posing natural selection to have been the only cause
of co-adaptation may be "found in the fact that
the very thing said to be impossible by variation
and natural selection, has been again and again
affected by variation and artificial selection V* This
analogy (which Darwin had already and very properly
adduced with regard to the blending of adaptations)
he enforces by special illustrations ; but he does not
appear to perceive that it misses the whole and
only point of the "difficulty" against which it is
brought. For the case which his analogy sustains
is not that which Darwin, Spencer, Broca and others,
mean by co-adaptation-, it is the case of a blending
of adaptations. It is not the case where adaptation
\s first initiated in spite of intercrossing, by a fortuitous
concurrence of variations each in itself being with-
out adaptive value : it is the case where adaptation
is afterwards increased by means of intercrossing ^

* E. g. Origin of Species, p. 178.
■ Darwinism, p. 418.

F 2

68 Darwin^ and after Danmn.

through the blending of variations each of which
has always been in itself of adaptive value.

From this I hope it will be apparent that the only-
way in which the " difficulty " from co-adaptation can
be logically met by the ultra-Darwinian school, is by
denying that the phenomenon of co-adaptation (as
distinguished from the blending of adaptations) is ever
to be really met with in organic nature. It may be
argued that in all cases where co-adaptation appears
to occur, closer examination will show that the facts
are really due to a blending of adaptations. The
characters A -I- B -f- C -f- D, which are now found united
in the same organism, and. as thus united, all conspiring
to a common end. may originally have been distri-
buted among different organisms, where they severally
subserved some other ends — or possibly the same
end, though in a less efficient manner. Obviously,
however, in this case their subsequent combination
in the same organism would not be an instance of
co-adaptation, but merely of an advantageous blend-
ing together of already existing adaptations. This
argument, or rejoinder, has in point of fact been
adopted by Professor Meldola, he believes that all
cases of seeming co-adaptation are thus due to a
mere blending of adaptations ^ Of course, if this
position can be maintained, the whole difficulty

' Nature, vol. xliii. pp. 410, 557 ; vol. xliv. pp. 7, 29. I say
"adopted," because I had objected to his quoting the analogy of artificial
selection, and stated, as above, that the only way to meet Mr. Spencer s
"difficulty" was to deny the fact of co-adaptation as. ever occurring in
any case. It then appeared that Professor Meldola agreed with me as to
this. But I do not yet understand why, if such were his view, he began
by endorsing Mr. Wallace's analogy from artificial selection — i. e.
confusing the case of co-adaptation with that of the blending of adapta-
tions. If any one denies the fact of co-adaptation, he cannot assist his

Characters, Hereditary and Acquired. 69

from co-adaptation would lapse. But even then it
would lapse on the ground of fact. It would not
have been overturned, or in any way affected, by
Wallace's argument from artificial selection. For, in
that event, no such argument would be required, and,
if adduced, would be irrelevant, since no one has
ever alleged that there is any difficulty in under-
standing the mere confluence of adaptations by free-
intercrossing of the best adapted.

Now, if we are agreed that the only question in debate
is the question of fact whether or not co-adaptation
ever occurs in nature, it appears to me that the best
field for debating the question is furnished by the
phenomena of reflex action. I can well perceive that
the instances adduced by Broca and Spencer in support
of their common argument — such as the giraffe, the
elk, &c. — are equivocal. But I think that many
instances which may be adduced of reflex action are
much more to the point. For it belongs to the very
nature of reflex action that it cannot work unless
all parts of the machinery concerned are already pre-
sent, and already co-ordinated in the same organism.
It would be useless, in so far as such action is con-
cerned if the afferent and efferent nerves, the nerve-
centre, and the muscles organically grouped together,
were not all present from the very first in the same
individuals, and from the very first were not co-
ordinated as a definite piece of organic machinery. ,

With respect to reflex actions, therefore, it is
desirable to begin by pointing out how widely the

denial by arguing the totally different fact that adaptations may be
blended by free intercrossing ; for this latter fact has never been ques-
tioned, and has nothing to do with the one which he engaged in
disputing.

TO Darwin^ and after Darwin,

adaptations which they involve differ from those where
no manufacture, so to speak, of special machinery is
required. Thus, it is easy to understand how natural
selection alone is capable of gradually accumulating
congenital variations in the direction of protective
colouring ; of mimicry ; of general size, form, mutual
correlation of parts as connected with superior strength,
fleetness, agility, &c. ; of greater or less development
of particular parts, such as legs, wings, tails, &c. For
in all such cases the adaptation which is in process of
accumulation is, from its very commencement and
throughout each of its subsequent stages, of use in
the struggle for existence. And inasmuch as all the
individuals of each successive generation vary round
the specific mean which characterized the preceding
generation, there will always be a sufficient number of
individuals which present congenital variations of the
kind required for natural selection to seize upon,
without danger of their being swamped by free in-
tercrossing— as Mr. Wallace has very ably shown in
his Darwinism. But this law of averages can apply
only to cases where single structures— or a single
group of correlated structures — are already present,
and already varying round a specific mean. The case
is quite different where a co-ordination of structures is
required for the performance oidi previously non-existejit
reflex action. For some, at least, of these structures
must be new, as must also be the function which all of
them first conspire to perform. Therefore, neither the
new elements of structure, nor the new combination of
structures, can have been previously given as varying
round a specific mean. On the contrary, a very
definite piece of machinery, consisting of many co-

Characters, Hereditary and Acquired. 71

ordinated parts, must somehow or other be or'ginated
in a high degree of working efficiency, before it can
be capable of answering its purpose in the prompt
performance of a particular action under particular
circumstances of stimulation. Lastly, such pieces of
machinery are always of a highly delicate character,
and usually involve so immensely complex a co-
ordination of mutually dependent parts, that it is only
a physiologist who can fully appreciate the magnitude
of the distinction between " adaptations " of this kind,
and " adaptations " of the kind which arise through
natural selection seizing upon congenital variations as
these oscillate round a specific mean.

Or the whole argument may be presented in another
form, under three different headings, thus : —

In the first place, it will be evident from what has
just been said, that such a piece of machinery as is con-
cerned in even the simplest reflex action cannot have
occurred in any considerable number of individuals
of a species, when it first begati to be constructed.
On the contrary, if its origin were dependent on con-
genital variations alone, the needful co-adaptation of
parts which it requires can scarcely have happened to
occur in more than a very small percentage of cases —
even if it be held conceivable that by such means
alone it should ever have occurred at all. Hence,
instead of preservation and subsequent improvement
having taken place in consequence of free intercrossing
among all individuals of the species (as in the cases
of protective colouring, &c., where adaptation has no
reference to any mechanical co-adaptation of parts),
they must have taken place in spite of such inter-
crossing.

72 Darwin, and after Darwin,

In the second place, adaptations due to organic
machineries of this kind differ in another all-important
respect from those due to a summation of adaptive
characters which are already present and already-
varying round a specific mean. The latter depend for
their summation upon the fact — not merely, as just
stated, that they are already present, already varying
round a specific mean, and therefore owe their pro-
gressive evolution to free intercrossing, but also — that
they admit of very different degrees of adaptation. It
is only because the degree of adaptation in generation
B is superior to that in generation A that gradual
improvement in respect of adaptation is here possible.
In the case of protective resemblance, for example,
a very imperfect and merely accidental resemblance
to a leaf, to another insect, &c., may at the first start
have conferred a sufficient degree of adaptive imitation
to count for something in the struggle for life ; and, if
so, the basis would be given for a progressive building
up by natural selection of structures and colours
in ever-advancing degrees of adaptive resemblance.
There is here no necessity to suppose — nor in point
of feet is it ever supposed, since the supposition
would involve nothing short of a miracle — that such
extreme perfection in this respect as we now so fre-
quently admire has originated suddenly in a single
generation, as a collective variation of a congenital
kind affecting simultaneously a large proportional
number of individuals. But in the case of a reflex
mechanism — which may involve even greater marvels
of adaptive adjustment, and all the parts of which
must occur in the same individuals to be of any
use — it is necessary to suppose some such sudden

Characters^ Hereditary and Acquired. 73

and collective origin in some very high degree of
efficiency, if natural selection has been the only
principle concerned in afterwards perfecting the
mechanism. For it is self-evident that a reflex action,
from its very nature, cannot admit of any great
differences in its degrees of adaptation : if it is to
work at all, so as to count for anything in the struggle
for life, it must already be given in a state of working
efficiency. So that, unless we invoke either the
doctrine of " prophetic types " or the theory of sudden
creations, I confess I do not see how we are to explain
either the origin, or the development, of a reflex
mechanism by means of natural selection alone.

Lastly, in the third place, even when reflex
mechanisms have been fully formed^ it is often beyond
the power of sober credence to believe that they now
are, or ever can have been, of selective value in the
struggle for existence, as I will show further on. And
such cases go to fortify the preceding argument. For
if not conceivably of selective value even when com-
pletely evolved, much less can they conceivably have
been so through all the stages of their complex
evolution back to their very origin. Therefore, sup-
posing for the present that there are such cases of
reflex action in nature, neither their origin nor their
development can conceivably have been due to
natural selection alone. The Lamarckian factors,
however, have no reference to degrees of adaptation,
any more than they have to degrees of complexity.
No question of value, as selective or otherwise, can
obtain in their case : neither in their case does any
difficulty obtain as regards the co- adaptation of
severally useless parts.

74 Darwin, and after Darwin,

Now, if all these distinctions between the Dar-
winian and Lamarckian principles are valid — and
I cannot see any possibility of doubt upon this point
— strong evidence in favour of the latter would be
furnished by cases (if any occur) where structures,
actions, instincts, &c., although of some adaptive
value, are nevertheless plainly not of selective value.
According to the ultra-Darwinian theory, no such
cases ought ever to occur : according to the theory
of Darwin himself, they ought frequently to occur.
Therefore a good test, or criterion, as between these
different theories of organic evolution is furnished by
putting the simple question of fact — Can we, or can
we not, show that there are cases of adaptation where
the degree of adaptation is so small as to be incom-
patible with the supposition of its presenting a selective
value? And if we put the wider question — Are there
any cases where the co-adaptation of severally useless
parts has been brought about, when even the re-
sulting whole does not present a selective value? —
then, of course, we impose a still more rigid test.

Well, notwithstanding the difficulty of proving such
a negative as the absence of natural selection where
adaptive development is concerned, I believe that there
are cases which conform to both these tests simul-
taneously ; and, moreover, that they are to be found in
most abundance where the theory of use-inheritance
would most expect them to occur — namely, in the
province of reflex action. For the very essence of
this theory is the doctrine, that constantly associated
use of the same parts for the performance of the same
action will progressively organize those parts into
a reflex mechanism — no matter how high a degree of

Character Sy Hereditary and Acquired, 75

co-adaptation may thus be reached on the one hand,
or how low a degree of utilitarian value on the other.

Having now stated the general or abstract prin-
ciples which I regard as constituting a defence of
the Lamarckian factors, so far as this admits of
being raised on grounds of physiology, we will now
consider a few concrete cases by way of illustra-
tion. It is needless to multiply such cases for the
mere purpose of illustration. For, on reading those
here given, every physiologist will at once perceive
that they might be added to indefinitely. The
point to observe is, the relation in which these
samples of reflex action stand to the general
principles in question ; for there is nothing unusual
in the samples themselves. On the contrary, they
are chosen because they are fairly typical of the
phenomena of reflex action in general.

In our own organization there is a reflex mechanism
which ensures the prompt withdrawal of the legs
from any source of irritation supplied to the feet.
For instance, even after a man has broken his spine
in such a manner as totally to interrupt the func-
tional continuity of his spinal cord and brain,
the reflex mechanism in question will continue to
retract his legs when his feet are stimulated by
a touch, a burn, &c. This responsive action is
clearly an adaptive action, and, as the man neither
feels the stimulation nor the resulting movement,
it is as clearly a reflex action. The question now is
as to the mode of its origin and development.

I will not here dwell upon the argument from
co-adaptation, because this may be done more
efTectually in the case of more complicated reflex

76 Darwin^ and after Darwin.

actions, but will ask whether we can reasonably
hold that this particular reflex action — comparatively
simple though it is — has ever been of selective
value to the human species, or to the ancestors
thereof? Even in its present fully-formed con-
dition it IS fairly questionable whether it is of any
adaptive value at all. The movement performed is
no doubt an adaptive movement ; but is there any
occasion upon which the reflex mechanism con-
cerned therein can ever have been of adaptive use}
Until a man's legs have been paralyzed as to
their voluntary motion, he will always promptly
withdraw his feet from any injurious source of
irritation by means of his conscious intelligence.
True, the reflex mechanism secures an almost in-
appreciable saving in the time of response to a
stimulus, as compared with the time required for
response by an act of will ; but the difference is
so exceedingly small, that we can hardly suppose
the saving of it in this particular case to be
a matter of any adaptive — much less selective
— importance. Nor is it more easy to suppose
that the reflex mechanism has been developed by
natural selection for the purpose of replacing volun-
tary action when the latter has been destroyed or
suspended by grave spinal injury, paralysis, coma,
or even ordinary sleep. In short, even if for the
sake of argument we allow it to be conceivable that
any single human being, ape, or still more distant
ancestor, has ever owed its life to the possession of
this mechanism, we may still be certain that not one
in a million can have done so. And, if this is the
case with regard to the mechanism as now fully

Characters y Hereditary and Acquired. 77

constructed, still more must it have been the case
with regard to all the previous stages of construction.
For here, without elaborating the point, it would
appear that a process of construction by survival of
the fittest alone is incomprehensible.

On the other hand, of course, the theory of use-
inheritance furnishes a fully intelligible — whether or not
a true — explanation. For those nerve-centres in the
spinal cord which co-ordinate the muscles required for
retracting the feet are the centres used by the will
for this purpose. And, by hypothesis, the frequent
use of them for this purpose under circumstances
of stimulation which render the muscular response
appropriate, will eventually establish an organic
connexion between such response and the kind of
stimulation to which it is appropriate — even though
there be no utilitarian reason for its establish-
ment ^ To invert a phrase of Aristotle, we do not
frequently use this mechanism because we have it
(seeing that in our normal condition there is no
necessity for such use) ; but, by hypothesis, we have
it because we have frequently used its several elements
in appropriate combination.

I will adduce but one further example in illustra-
tion of these general principles — passing at once
from the foregoing case of comparative simplicity
to one of extreme complexity.

There is a well-known experirhent on a brainless
frog, which reveals a beautiful reflex mechanism in

* It may be said, with regard to this particular reflex, that it may
perhaps be, so to speak, a mechanical accident, arising from the
contiguity of the sensory and motor roots in the cord. But as this
suggestion cannot apply to other reflexes presently to be adduced, it need
not be considered.

78 Darwin, and after Darwin,

the animal, whereby the whole body is enabled con-
tinually to readjust its balance on a book (or any
other plane surface), as this is slowly rotated on
a horizontal axis. So long as the book is lying flat,
the frog remains motionless ; but as soon as the book
is tilted a little, so that the frog is in danger of
slipping off, all the four feet begin to crawl up the
hill ; and the steeper the hill becomes, the faster
they crawl. When the book is vertical, the frog
has reached the now horizontal back, and so on.
Such being the facts, the question is — How can the
complicated piece of machinery thus implied have
been developed by natural selection? Obviously it
cannot have been so by any of the parts concerned
having been originally distributed among different
individuals, and afterwards united in single individuals
by survival (i.e. free intercrossing) of the fittest.
In other words, the case is obviously one of co-adap-
tation, and not one of the blending of adaptations.
Again, and no less obviously, it is impossible that
the co-adaptation can have been gradually developed
by natural selection, because, in order to have been
so, it must by hypothesis have been of some degree
of use in every one of its stages ; yet it plainly
cannot have been until it had been fully perfected
in all its astonishing complexity*.

* Of course it will be observed that the question is not with regard
to the development of all the nerves and muscles concerned in this
particular process. It is as to the development of the co-ordinating
centres, which thus so delicately respond to the special stimuli furnished
by variations of angle to the horizon. And it is as inconceivable in this
case of reflex action, as it is in almost every other case of reflex action,
that the highly specialized machinery required for performing the adaptive
function can ever have had its origin in the performance of any other

I

Characters, Hereditary and Acquired, 79

Lastly, not only does it thus appear impossible
that during all stages of its development — or while
as yet incapable of performing its intricate function —
this nascent mechanism can have had any adaptive
value ; but even as now fully developed, who will
venture to maintain that it presents any selective
value? As long as the animal preserves its brain,
it will likewise preserve its balance, by the exercise
of its intelligent volition. And, if the brain were
in some way destroyed, the animal would be
unable to breed, or even to feed ; so that natural
selection can never have had any opportunity, so
to speak, of developing this reflex mechanism in
brainless frogs. On the other hand, as we have just
seen, we cannot perceive how there can ever have
been any raison d'etre for its development in normal
frogs — even if its development were conceivably
possible by means of this agency. But if practice
makes perfect in the race, as it does in the individual,
we can immediately perceive that the constant habit
of correctly adjusting its balance may have gradually
developed, in the batrachian organization, this non-
necessary reflex ^.

function. Indeed, a noticeable peculiarity of reflex mechanisms as a class
is the highly specialized character of the functions which their highly
organized structures subserve.

' We meet with a closely analogous refltx mechanism in brainless
vertebrata of other kinds ; but these do not furnish such good test cases,
because the possibility of natural selection cannot be so efficiently
attenuated. The perching of brainless birds, for instance, at once refers
us to the roosting of sleeping birds, where the reflex mechanism
concerned is clearly of high adaptive value. Therefore such a case is
not available as a test, although the probability is that birds have
inherited their balancing mechanisms from their sauropsidian ancestors,
where it would have been of no such adaptive importance.

8o Darwin, and after Darwin,

And, of course, this example — like that of with-
arawing the feet from a source of stimulation, which
a frog will do as well as a man — does not stand alone.
Without going further a-field than this same animal,
any one who reads, from our present point of view,
Goltz s work on the reflex actions of the frog, will
find that the great majority of them — complex and
refined though most of them are — cannot conceivably
have ever been of any use to any frog that was in
undisturbed possession of its brain.

Hence, not to occupy space with a reiteration of
facts all more or less of the same general kind,
and therefore all presenting identical difficulties to
ultra-Darwinian theory, I shall proceed to give two
others which appear to me of particular interest in
the present connexion, because they furnish illus-
trations of reflex actions in a state of only partial
development, and are therefore at the present moment
demonstrably useless to the animal which displays
them.

Many of our domesticated dogs, when we gently
scratch their sides and certain other parts of the body,
will themselves perform scratching movements with
the hind leg of the same side as that upon which tht
irritation is being supplied. According to Goltz \
this action is a true reflex ; for he found that it is
performed equally well in a dog which has been
deprived of its cerebral hemispheres, and therefore
of its normal volition. Again, according to Haycraft^,

* Pfliigers Archiv, Bd. xx. s. 23 (1879).

" Brain, part xlviii, pp. 516-19 (1889). — There is still better proof
of this in the case of certain rodents. For instance, observing that rats
and mice are under the necessity of very frequently scratching themselves
with their hind-feet, I tried the experiment of removing the latter from

Characters, Hereditary and Acquired. 81

this reflex is congenital, or not acquired during the
life-time of each individual dog. Now, although the
action of scratching is doubtless adaptive, it appears
to me incredible that it could ever have become
organized into a congenital reflex by natural selec-
tion. For, in order that it should, the scratching
away fleas would require to have been a function of
selective value. Yet, even if the irritation caused by
fleas were supposed to be so far fatal in the struggle
for existence, it is certain that they would always be
scratched away by the conscious intelligence of each
individual dog ; and, therefore, that no advantage
could be gained by organizing the action into a
reflex. On the other hand, if acquired characters
are ever in any degree transmitted, it is easy to
understand how so frequently repeated an action
should have become, in numberless generations of
dogs, congenitally automatic.

So much for the general principle of selective
value as applied to this particular case. And simi-
larly, of course, we might here repeat the application

newly-born individuals — i.e. before the animals were able to co-ordinate
their movements, and therefore before they had ever even attempted to
scratch themselves. Notwithstanding that they were thus destitute of
individual experience with regard to the benefit of scratching, they began
their scratching movements with their stumps as soon as they were
capable of executing co-ordinated movements, and afterwards continued
to do so till the end of their lives with as much vigour and frequency as
nnmutilated animals. Although the stumps could not reach the scats
of irritation which were bent towards them, they used to move rapidly
in the air for a lime sufficient to have given the itching part a good
scratch, had the feet been present — after which the animals would resume
their sundry other avocations with apparent satisfaction. These facts
showed the hereditary response to irritation by parasites to be so strong,
that even a whole life-time's experience of its futility made no difference
in the frequency or the vigour thereof.
II. G

82 Darwin, and after Darwin,

of all the other general principles, which have just
been applied in the two preceding cases. But it is
only one of these other general principles which
I desire in the present case specially to consider,
for the purpose of considering more closely than
hitherto the difficulty which this principle presents
to ultra-Darwinian theory.

The difficulty to which I allude is that of under-
standing how all the stages in the development of
a reflex action can have been due to natural selection,
seeing that, before the reflex mechanism has been
sufficiently elaborated to perform its function, it can-
not have presented any degree of utility. Now the
particular force of the present example, the action
of scratching — as also of the one to follow — consists
in the fact that it is a case where a reflex action is
not yet completely organized. It appears to be only
in course of construction, so that it is neither in-
variably present, nor, when it is present, is it ever
fully adapted to the performance of its function.

That it is not invariably present (when the brain
is so) may be proved by trying the simple experi-
ment on a number of puppies — and also of full-
grown dogs. Again, that even when it is present
it is far from being fully adapted to the perform-
ance of its function, may be proved by observing
that only in rare instances does the scratching
leg succeed in scratching the place which is being
irritated. The movements are made more or less at
random, and as often as not the foot fails to touch
the body at any place at all. Hence, althoui;h we
have a "prophecy" of a reflex action well designed
for the discharge of a particular function, at present

Characters y Hereditary and Acquired. 83

the machinery is not sufficiently perfected for the
adequate discharge of that function. In this impor-
tant respect it differs from the otherwise closely
analogous reflex action of the frog, whereby the
foot of the hind leg is enabled to localize with
precision a seat of irritation on the side of the
body. But this beautiful mechanism in the frog can-
not have sprung into existence ready formed at any
historical moment in the past history of the phyla.
It must have been the subject of a more or less
prolonged evolution, in some stage of which it must
presumably have resembled the now nascent scratch-
ing reflex of the dog, in making merely abortive
attempts at localizing the seat of irritation — supposing,
of course, that some physiologist had been there to
try the experiment by first removing the brain.
Now, even if one could imagine it to be, either in the
frog or in the dog, a matter of selective importance that
so exceedingly refined a mechanism should have been
developed for the sole purpose of inhibiting the bites
of parasites — which in every normal animal would
certainly be discharged by an intentional performance
of the movements in question,— even if, in order to
save an hypothesis at all costs, we make so violent
a supposition as this, still we should do so in vain.
For it would still remain undeniably certain that
the reflex mechanism is not of any selective value.
Even now the mechanism in the dog is not sufficiently
precise to subserve the only function which occasionally
and abortively it attempts to perform. Thus it has
all the appearance of being but an imitating shadow
of certain neuro-muscular adjustments, which have
been habitually performed in the canine phyla by a

G 2

84 Darwin^ and after Darwin.

volitional response to cutaneous irritation. Were
it necessary, this argument might be strengthened
by observing that the reflex action is positively
improved by removal of the brain.

The second example of a nascent reflex in dogs
which I have to mention is as follows.

Goltz found that his brainless dogs, when wetted
with water, would shake themselves as dry as possible,
in just the same way as normal dogs will do under
similar circumstances. This, of course, proves that
the shaking movements may be performed by a
reflex mechanism, which can have no other function
to perform in the organization of a dog, and which,
besides being of a highly elaborate character, will
respond only to a very special kind of stimulation.
Now, here also I find that the mechanism is con-
genital, or not acquired by individual experience.
For the puppies on which I experimented were kept
indoors from the time of their birth — so as never
to have had any experience of being wetted by rain,
&c. — till they were old enough to run about with
a full power of co-ordinating their general movements.
If these young animals were suddenly plunged into
water, the shock proved too great : they would
merely lie and shiver. But if their feet alone were
wetted, by being dipped in a basin of water, the
puppies would soon afterwards shake their heads in
the peculiar manner which is required for shaking
water off the ears, and which in adult dogs consti-
tutes the first phase of a general shaking of the
whole body.

Here, then, we seem to have good evidence of all
the same facts which were presented in the case of the

Characters^ Hereditary and Acquired, 85

scratching reflex. In the first place, co-adaptation
is present in a very high degree, because this shaking
reflex in the dog, unlike the skin-twitching reflex
in the horse, does not involve only a single muscle,
or even a single group of muscles : it involves more
or less the co-ordinated activity of many voluntary
muscles all over the body. Such, at any rate, is
the case when the action is performed by the in-
telligent volition of an adult dog ; and if a brainless
dog, or a young puppy, does not perform it so
extensively or so vigorously, this only goes to prove
that the reflex has not yet been sufficiently developed
to serve as a substitute for intelligent volition — i.e.
that it is useless, or a mere organic shadow of the
really adaptive substance. Again, even if this nascent
reflex had been so far developed as to have been
capable of superseding voluntary action, still we may
fairly doubt whether it could have proved of selective
value. For it is questionable whether the imme-
diate riddance of water after a wetting is a matter
of life and death to dogs in a state of nature.
Moreover, even if it were, every individual dog would
always have got rid of the irritation, and so of
the dan^^er, by means of a voluntary shake — with
the double result that natural selection has never
had any opportunity of gradually building up
a special reflex mechanism for the purpose of
securing a shake, and that the canine race have
not had to wait for any such unnecessary process.
Lastly, such a process, besides being unnecessary,
must surely have been, under any circumstances,
impossible. For even if we ^yere to suppose — again
for the sake of saving an hypothesis at any

86 DarwiUy and after Darwin.

cost — that the presence of a fully-formed shaking
reflex is of selective value in the struggle for exist-
ence, it is perfectly certain that all the stages
through which the construction of so elaborate a
mechanism must have passed could not have been,
under any circumstances, of any such value.

But, it is needless to repeat, according to the
hypothesis of use-inheritance, there is no necessity
to suppose that these incipient reflex mechanisms
are of any value. If function produces structure in
the race as it does in the individual, the voluntary
and frequently repeated actions of scratching and
shaking may very well have led to an organic
integration of the neuro-muscular mechanisms con-
cerned. Their various parts having been always
co-ordinated for the performance of these actions by
the intelligence of innumerable dogs in the past,
their co-adapted activity in their now automatic
responses to appropriate stimuli presents no diflficulty.
And the consideration that neither in their prospec-
tively more fully developed condition, nor, a fortiori,
in their present and all previous stages of evolution,
can these reflex mechanisms be regarded as present-
ing any selective — or even so much as any adaptive
— value, is neither more nor less than the theory of
use-inheritance would expect.

Thus, with regard to the phenomena of reflex action
in general, all the facts are such as this theory requires,
while many of the facts are such as the theory of
natural selection alone cannot conceivably explain.
Indeed, it is scarcely too much to say, that most
of the facts are such as directly contradict the latter
theory in its application to them. But, be this

Characters^ Hereditary and Acquired. 87

as it may, at present there are only two hypo-
theses in the field whereby to account for the facts
of adaptive evolution. One of these hypotheses
is universally accepted, and the only question is
whether we are to regard it as alone sufficient to ex-
plain all the facts. The other hypothesis having been
questioned, we can test its validity only by finding
cases which it is fully capable of explaining, and
which do not admit of being explained by its com-
panion hypothesis. I have endeavoured to show
that we have a large class of such cases in the
domain of reflex action, and shall next endeavour to
show that there is another large class in the domain
of instinct.

If instinct be, as Professor Hering, Mr. Samuel
Butler, and others have argued, "hereditary habit*'—
i. e. if it comprises an element of transmitted ex*
perience — we at once find a complete explanation of
many cases of the display of instinct which otherwise
remain inexplicable. For although a large number —
or even, as I believe, a large majority — of instincts
are explicable by the theory of natural selection alone,
or by supposing that they were gradually developed
by the survival of fortuitous variations in the way of
advantageous psychological peculiarities, this only
apphes to comparatively simple instincts, such as that
of a protectively coloured animal exhibiting a prefer-
ence for the surroundings which it resembles, or even
adopting attitudes in imitation of objects which occur
in such surroundings. But in all cases where instincts
become complex and refined, we seem almost com-
pelled to accept Darwin's view that their origin is to

88 Darwin^ and after Darwin.

be sought in consciously intelligent adjustments on
the part of ancestors.

Thus, to give only one example, a species of
Sphex preys upon caterpillars, which it stings in
their nerve-centres for the purpose of para' y zing,
without killing them. The victims, when thus ren-
dered motionless, are then buried with the eggs of
the Sphex, in order to serve as food for her larvae
which subsequently develop from these eggs. Now,
in order thus to paralyze a caterpillar, the Sphex has
to sting it successively in nine minute and particular
points along the ventral surface of the animal — and
this the Sphex unerringly does, to the exclusion
of all other points of the caterpillar's anatomy. Well,
such being the facts — according to M. Fabre, who
appears to have observed them carefully — it is con-
ceivable enough as Darwin supposed \ that the
ancestors of the Sphex, being like many other hymen-
opterous insects highly intelligent, should have
observed that on stinging caterpillars in these particular
spots a greater amount of effect was produced than
could be produced by stinging them anywhere else ;
and, therefore, that they habitually stung the cater-
pillars in these places only, till, in course of time, this
originally intelligent habit became by heredity instinc-
tive. But now, on the other hand, if we exclude the
possibility of this explanation, it appears to me in-
credible that such an instinct should ever have been
evolved at all ; for it appears to me incredible that
natural selection, unaided by originally intelligent
action, could ever have developed such an instinct

* For details of his explanation of this particular case, for which
1 particularly inquired, see Mental Evolution in Animals^ pp. 301-2.

Characters, Hereditary and Acquired, 89

out of merely fortuitous variations — there being, by
hypothesis, nothing to determine variations of an
insect's mind in the direction of stinging caterpillars
only in these nine intensely localized spots ^.

Again, there are not a few instincts which appear
to be wholl\' useless to their possessors, and others
again which appear to be even deleterious. The
dusting over of their excrement by certain freely-
roaming carnivora ; the choice by certain herbivora
of particular places on which to void their urine, or
in which to die ; the howling of wolves at the moon ;
purring of cats, &c., under pleasurable emotion ; and
sundry other hereditary actions of the same appar-
ently unmeaning kind, all admit of being readily
accounted for as useless habits originally acquired
in various ways, and afterwards perpetuated by
heredity, because not sufficiently deleterious to have
been stamped out by natural selection -. But it does
not seem possible to explain them by survival of the
fittest in the struggle for existence.

Finally, in the case of our own species, it is self-
evident that the aesthetic, moral, and religious instincts
admit of a natural and easy explanation on the
hypothesis of use-inheritance, while such is by no
means the case if that hypothesis is rejected. Our
emotions of the ludicrous, of the beautiful, and of the
sublime, appear to be of the nature of hereditary
instincts ; and be this as it may, it would further
appear that, whatever else they may be, they are
certainly not 01 a life-preserving character. And

» Note B.

' For fuller treatment see Mental Evolution in Animals^ pp. 274-385,
378-379» 381-383.

90 Darwifiy and after Darwin.

although this cannot be said of the moral sense when
the theory of natural selection is extended from the
individual to the tribe, still, when we remember the
extraordinary complexity and refinement to which
they have attained in civilized man, we may well
doubt whether they can have been due to natural
selection alone. But space forbids discussion of this
large and important question on the present occasion.
Suffice it therefore to say, that I doubt not Weismann
himself would be the first to allow that his theory of
heredity encounters greater difficulties in the domain
of ethics than in any other — unless, indeed, it be that
of religion ^.

I have now given a brief sketch of the indirect
evidence in favour of the so-called Lamarckian factors,
in so far as this appears fairly deducible from the
facts of reflex action and of instinct. It will now be
my endeavour to present as briefly what has to be said
against this evidence.

As previously observed, the facts of reflex action
have not been hitherto adduced in the present con-
nexion. This has led me to occupy considerably
more space in the treatment of them than those of
instinct. On this account, also, there is here nothing
to quote, or to consider, per contra. On the other
hand, however, Weismann has himself dealt with the
phenomena of instinct in animals, though not, I think,
in man— if we except his brilliant essay on music.
Therefore let us now begin this division of our

* For an excellent essay on the deleterious character of early forms of
religion from a biological point of view, see the Hon. Lidy Welby, An
Apparent Paradox in Mentai Evolution {joynrn. AnXhxo^. Inst. May 1891).

Characters, Hereditary and Acquired. 91

subject by briefly stating, and considering, what he
has said upon the subject.

The answer of Weismann to difficulties which arise
against the ultra-Darwinian theory in the domain of
instinct, is as follows : —

" The necessity for extreme caution in appealing to the sup-
posed hereditary effects of use, is well shown in the case of those
numerous instincts which only come into play once in a life-time,
and which do not therefore admit of improvement by practice.
The queen-bee takes her nuptial flight only once, and yet how
many and complex are the instincts and the reflex mechanisms
which come into play on that occasion. Again, in many insects
the deposition of eggs occurs but once in a life-time, and yet
such insects always fulfil the necessary conditions with unfailing
accuracy '."

But in this rejoinder the possibility is forgotten,
that although such actions are ftow performed only
once in the individual life-time, originally — i. e. when
the instincts were being developed in a remote
ancestry — they may have been performed on many
frequent and successive occasions during the individual
life-time. In all the cases quoted by Weismann,
instincts of the kind in question bear independent
evidence of high antiquity, by occurring in whole
genera (or even families), by being associated with
peculiar and often highly evolved structures required
for their performance, and so on. Consequently, in
these cases ample time has been allowed for subse-
quent changes of habit, and of seasonal alterations
with respect to propagation — both these things being
of frequent and facile occurrence among animals of all
kinds, even within periods which fall under actual
' Essays, i. p. 93.

92 Darwin, and after Darwin.

observation. Nevertheless, I do not question that
there are instinctive activities v^^hich, as far as we are
able to see, can never have been performed more
than once in each individual life- time ^. The fact,
however, only goes to show what is fully admitted —
that some instincts (and even highly complex instincts)
have apparently been developed b\' natural selection
alone. Which, of course, is not equivalent to showing
that all instincts must have been developed by natural
selection alone. The issue is not to be debated on
general grounds like this, but on those of particular
cases. Even if it were satislactorily proved that the
instincts of a queen-bee have been developed by
natural selection, it would not thereby be proved
that such has been the case with the instincts of
a Sphex wasp. One can very well understand how
the nuptial fliglit of the former, with all its associated
actions, may have been brought about by natural
selection alone ; but this does not help us to under-
stand how the peculiar instincts of the latter can have
been thus caused.

Strong evidence in favour of Weismann's views
does, however, at first sight seem to be furnished by
social hymenoptera in other respects. For not only
does the queen present highly specialized and alto-
gether remarkable instincts ; but the neuters present
totally different and even still more remarkable
instincts — which, moreover, are often divided into
two or more classes, corresponding with the different
'' castes.*' Yet the neuters, being barren females,
never have an opportunity of bequeathing their
instincts to progeny. Thus it appears necessary to

1 See Mental Evolution in Animals y pp. 377-8.

Characters, Hereditary and Acquired, 93

suppose that the instincts of all the different castes of
neuters are latent in the queen and drones, together
with the other instincts which are patent in both.
Lastly, it seems necessary to suppose that all thi<?
wonderful organization of complex and segregated
instincts must have been built up by natural selection
acting exclusively on the queens and drones — seeing
that these exercise their own instincts only once in
a life-time, while, as just observed, the neuters cannot
possibly bequeath their individual experience to
progeny. Obviously, however, natural selection must '
here be supposed to be operating at an immense
disadvantage ; for it must have built up the often
diverse and always complex instincts of neuters, not
directly, but indirectly through the queens and drones,
which never manifest any of these instincts themselves.
Now Darwin fully acknowledged the difficulty of
attributing these results to the unaided influence of
natural selection ; but the fact of neuter insects being
unable to propagate seemed to him to leave no
alternative. And so it seems to Weismann, who
accordingly quotes these instincts in support of his
views. And so it seemed to me, until my work
on Animal Intelligence was translated into French,
and an able Preface was supplied to that translation
by M. Perrier. In this Preface it is argued that we
are not necessarily obliged to exclude the possibility
of Lamarckian principles having operated in the
original formation of these instincts. On the contrary,
if such principles ever operate at all, Perrier shows
that here we have a case where it is virtually certain
that they must have operated. For although neuter
insects are now unable to propagate, their organiza-

94 Darwin^ and after Darwin.

tion indicates — if it does not actually prove — that
they are descended from working insects which were
able to propagate. Thus, in all probability, what we
now call a "hive" was originally a society of sexually
mature insects, all presenting the same instincts, both
as to propagation and to co-operation. When these
instincts, thus common to all individuals composing
the hive, had been highly perfected, it became of
advantage in the struggle for existence (between
different hives or communities) that the functions
of reproduction should devolve more upon some
individuals, while those of co-operation should devolve
more upon others. Consequently, this division of
labour began, and gradually became complete, as
we now find it in bees and ants. Perrier sustains
the hypothesis thus briefly sketched by pointing
to certain species of social hymenoptera where
we may actually observe different stages of the
process — from cases where all the females of the
hive are at the same time workers and breeders, up
to the cases where the severance between these func-
tions has become complete. Therefore, it seems to
me, it is no, longer necessary to suppose that in these
latter cases all the instincts of the (now) barren females
can only have been due to the unaided influence of
natural selection.

Nevertheless although I think that Perrier has
made good his position thus far, that his hypothesis
fails to account for some of the instincts which are
manifested by neuter insects, such as those which, so
far as I can see, must necessarily be supposed to
have originated after the breeding and working
functions had become separated — seeing that they

Characters^ Hereditary and Acquired. 95

appear to have exclusive reference to this peculiar
state of matters. Possibly, however, Perrier might
be able to meet each of these particular instincts,
by showing how they could have arisen out of
simpler beginnings, prior to the separation of the two
functions in question. There is no space to consider
such possibilities in detail ; but, until this shall
have been done, I do not think we are entitled to
conclude that the phenomena of instinct as presented
by neuter insects are demonstrably incompatible with
the doctrines of Lamarck — or, that these phenomena
are available as a logical proof of the unassisted
agency of natural selection in the case of instincts
in general ^

(B.)

Inherited Effects of Use and of Disuse,

There is no doubt that Darwin everywhere attaches
great weight to this line of evidence. Nevertheless,
in my opinion, there is equally little doubt that,
taken by itself, it is of immeasurably less weight than
Darwin supposed. Indeed, I quite agree with Weis-
mann that the whole of this line of evidence is
practically worthless ; and for the following reasons.

The evidence on which Darwin relied to prove

• \See H. Spencer, The Inadequacy of Natural Selection, A Rejoinder
to Professor Weismann^ Contemp. Rev. 1893 ; and Weismannism once
more ^hvdi.OcX. 1894 ; Weismann, The All- sufficiency of Natural Selection,
Ibid. 1893; and The Effect of Exteinal htfluences upon Development^
*' Romanes Lecture" 1S94: also Neuter Insects and Lamarckism,
W. Piatt Ball, Natural Science, Feb. 1894, and Neuter Insects and
Darwinism, J. T. Cunningham, Ibid. April 1894. C. LI. M.]

96 Darwin, and after Darwin,

the inherited effects of use and disuse was derived
from his careful measurements of the increase or
decrease which certain bones of our domesticated
animals have undergone, as compared with the cor-
responding bones of ancestral stocks in a state of
nature. He chose domesticated animals for these
investigations, because, while yielding unquestionable
cases of increased or diminished use of certain organs
over a large number of sequent generations, the results
were not complicated by the possible interference
of natural selection on the one hand, or by that
of the economy of nutrition on the other. For " with
highly-fed domesticated animals there seems to be
no economy of growth, or any tendency to the elimi-
nation of superfluous details^;'' seeing that, among
other considerations pointing in the same direction,
" structures which are rudimentary in the parent
species, sometimes become partially re-developed in
our domesticated productions^."

The method of Darwin's researches in this con-
nexion was as follows. Taking, for example, the case
of ducks, he carefully weighed and measured the
wing-bones and leg-bones of wild and tame ducks ;
and he found that the wing-bones were smaller,
while the leg-bones were larger, in the tame than in
the wild specimens. These facts he attributed to many
generations of tame ducks using their wings less, and
their legs more, than was the case with their wild
ancestry. Similarly he compared the leg-bones of
wild rabbits with those of tame ones, and so forth —
in all cases finding that where domestication had led
to increased use of a part, that part was larger than in

* Variation of Plants and Animals^ vol. ii. p. 289. • Ibid, p. 346.

Characters y Hereditary and Acquired, 97

the wild parent stock ; while the reverse was the case
with parts less used. Now, although at first sight
these facts certainly do seem to yield good evidence
of the inherited effects of use and disuse, they are
really open to the following very weighty objections.

First of all, there is no means of knowing how
far the observed effects may have been due to in-
creased or diminished use during only the individual
life-time of each domesticated animal. Again, and
this is a more important point, in all Darwin's
investigations the increase or decrease of a part
was estimated, not by directly comparing, say the
wing-bones of a domesticated duck with the wing-
bones of a wild duck, but by comparing the ratio
between the wing and leg bones of a tame duck
with the ratio between the wing and leg bones
of a wild duck. Consequently, if there be any reason
to doubt the supposition that a really inherited
decrease in the size of a part thus estimated is due
to the inherited effects of disuse, such a doubt will
also extend to the evidence of increased size being
due to the inherited effects of use. Now there is the
gravest possible doubt lying against the supposition
that any really inherited decrease in the size of a
part is due to the inherited effects of disuse. For
it may be — and, at any rate to some extent, must
be — due to another principle, which it .is strange that
Darwin should have overlooked. This is the prin-
ciple which Weismann has called Panniixia, and which
cannot be better expressed than in his own words : —

" A goose or a duck must possess strong powers of flight in the
natural state, but such powers are no longer necessary for
obtaining food when it is brought into the poultry-yard; so

II. II

98 Darwin^ and after Darwin.

that a rigid selection of individuals with well-developed wings
at once ceases among its descendants. Hence, in the course
of generations, a deterioration of the organs of flight must
necessarily ensue *.'*

Or, to state the case in another way: if any
structure which was originally built up by natural
selection on account of its use, ceases any longer
to be of so much use, in whatever degree it ceases
to be of use, in that degree will the premium before
set upon it by natural selection be withdrawn. And
the consequence of this withdrawal of selection as
regards that particular part will be to allow the
part to degenerate in successive generations. Such
is the principle which Weismann calls Panmixia,
because, by the withdrawal of selection from any
particular part, promiscuous breeding ensues with
regard to that part. And it is easy to see that
this principle must be one of very great importance
in nature ; because it must necessarily come into
operation in all cases where any structure or any
instinct has, through any change in the environment
or in the habits of a species, ceased to be useful.
It is likewise easy to see that its effect must be
the same as that which was attributed by Darwin
to the inherited effect of disuse ; and, therefore, that
the evidence on which he relied in proof of the
inherited effects both of use and of disuse is vitiated
by the fact that the idea of Panmixia did not occur to
him.

Here, however, it may be said that the idea first
occurred to me'^ just after the publication of the

* Essays, i. p. 90.

• Nature^ vol. ix. pp. 361-3, 440-1 ; and vol. x. p. 164.

Characters, Hereditary and Acquired. 99

last edition of the Origin of Species. I called the
principle the Cessation of Selection — which I still
think a better, because a more descriptive, term
than Panmixia ; and at that time it appeared to me,
as it now appears to Weismann, entirely to supersede
the necessity of supposing that the effect of disuse is
ever inherited in any degree at all. Thus it raised
the whole question as to the admissibility of La-
marckian principles in general ; or the question on
which we are now engaged touching the possible
inheritance of acquired, as distinguished from con-
genital, characters. But on discussing the matter
with Mr. Darwin, he satisfied me that the larger
question was not to be so easily closed. That is to
say, although he fully accepted the principle of the
Cessation of Selection, and as fully acknowledged
its obvious importance, he convinced me that there
was independent evidence for the transmission of
acquired characters, sufficient in amount to leave
the general structure of his previous theory unaffected
by what he nevertheless recognized as a factor which
must necessarily be added. All this I now mention
in order to show that the issue which Weismann
has raised since Darwin's death was expressly con-
templated during the later years of Darwin's life.
For if the idea of Panmixia— in the absence of which
Weismann's entire system would be impossible —
had never been present to Darwin's mind, we should
have been left in uncertainty how he would have
regarded this subsequent revolt against what are
generally called the Lamarckian principles ^.

Moreover, in this connexion we must take par-

* Appendix L

loo Darwifiy and after Darwin,

ticular notice that the year after I had published
these articles on the Cessation of Selection, and
discussed with Mr. Darwin the bearing of this prin-
ciple on the question of the transmission of acquired
characters, Mr. Galton followed with his highly
important essay on Heredity. For in this essay
Mr. Galton fully adopted the principle of the Cessa-
tion of Selection, and was in consequence the first
publicly to challenge the Lamarckian principles —
pointing out that, if it were thus possible to deny
the transmission of acquired characters in toto^ "we
should be relieved from all further trouble " ; but
that, if such characters are transmitted " in however
faint a degree, a complete theory of heredity must
account for them." Thus the question which, in its
revived condition, is now attracting so much attention,
was propounded in all its parts some fifteen or six-
teen years ago; and no additional facts or new
considerations of any great importance bearing upon
the subject have been adduced since that time. In
other words, about a year after my own conversations
with Mr. Darwin, the whole matter was still more
effectively brought before his notice by his own
cousin. And the result was that he still retained his
belief in the Lamarckian factors of organic evolution,
even niore strongly than it was retained either by
Mr. Galton or myself^.

We have now considered the line of evidence on
which Darwin chiefly relied in proof of the transmis-
sibility of acquired characters ; and it must be allowed
that this line of evidence is practically worthless.

* For a fuller statement of Mr. Galton*s theory of Heredity, and its
relation to Weismann's, see An Examination of Weismannism.

Characters^ Hereditary and Acquired. loi

What he regarded as the inherited effects of use and
of disuse may be entirely due to the cessation of
selection in the case of our domesticated animals,
combined with an active reversal of selection in the
case of natural species. And in accordance with
this view is the fact that the degeneration of disused
parts proceeds much further in the case of wild
species than it does in that of domesticated varieties.
For although it may be said that in the case of wild
species more time has been allowed for a greater
accumulation of the inherited effects of disuse than
can have been the case with domesticated varieties,
the alternative explanation is at least as probable —
that in the case of wild species the merely negative,
or passive, influence of the cessation of selection has
been continuously and powerfully assisted by the
positive, or active, influence of the reversal o{ selection,
through economy of growth and the general advantage
to be derived from the abolition of useless parts ^.

The absence of any good evidence of this direct
kind in favour of use-inheritance will be rendered
strikingly apparent to any one who reads a learned
and interesting work by Professor Semper ^ His
object was to show the large part which he believed
to have been played by external conditions of life in
directly modifying organic types — or, in other words,
of proving that side of Lamarckianism which refers
to the immediate action of the environment, whether
with or without the co-operation of use-inheritance
and natural selection. Although Semper gathered

* For a fuller explanation of the important difference between the
mere cessation and the actual reversal of selection, see Appendix L
' Animal Life, International Scientific Series, vol. xxxi.

I02 Darwin, and after Darwin,

together a great array of facts, the more carefully
one reads his book the more apparent does it become
that no single one of the facts is in itself conclusive
evidence of the transmission to progeny of char-
acters which are acquired through use-inheritance or
through direct action of the environment. Every one
of the facts is susceptible of explanation on the
hypothesis that the principle of natural selection
has been the only principle concerned. This, how-
ever, it must be observed, is by no means equivalent
to proving that characters thus acquired are not
transmitted. As already pointed out, it is imprac-
ticable with species in a state of nature to disso-
ciate the distinctively Darwinian from the possibly
Lamarckian factors ; so that even if the latter
are largely operative, we can only hope for direct
evidence of the fact from direct experiments on
varieties in a state of domestication. To this branch
of oiir subject, therefore, we will now proceed.

CHAPTER IV.

Characters as Hereditary and Acquired
{continued),

(C.)

Experimental Evidence in favour of the Inheritance
of Acquired Characters,

Notwithstanding the fact already noticed, that
no experiments have hitherto been published with
reference to the question of the transmission of
acquired characters \ there are several researches

* The experiments of Galton and Weismann upon this subject are
nugatory, as will be shown later on. But since the above was written
an important research has been published by Mr. Cunningham, of the
Marine Biological Association, For a full account I must refer the
reader to his forthcoming paper in the Philosophical Transactions. The
following is his own statement of the principal results : —

**A case which I have myself recently investigated experimentally
seems to me to support very strongly the theory of the inheritance of
acquired characters, I have shown that in normal flat-fishes, if the
lower side be artificially exposed to light for a long time, pigmen-
tation is developed on that side ; but when the exposure is commenced
while the specimens are still in process of metamorphosis, when'
pigment-cells are still present on the lower side, the action of light
does not prevent the disappearance of these pigment-cells. They
disappear as in individuals living under normal conditions, but after
prolonged exposure pigment-cells reappear. The first fact proves that
the disappearance of the pigment-cells from the lower side in the
metamorphosis is an hereditary character, and not a change produced in
each individual by the withdrawal of the lower side from the action
of light. On the other hand, the experiments show that the absence of

I04 Darwin, and after Darwin.

which, with other objects in view, have incidentally
yielded seemingly good evidence of such transmission.
The best-known of these researches — and therefore
the one with which I shall begin — is that of Brown-
Sequard touching the effects of certain injuries of the
nervous system in guinea-pigs.

During a period of thirty years Brown-Sdquard
bred many thousands of guinea-pigs as material for
his various researches; and in those whose parents
had not been operated upon in the ways to be
immediately mentioned, he never saw any of the
peculiarities which are about to be described. There-
fore the hypothesis of coincidence, at all events, must
be excluded. The following is his own summary
of the results with which we are concerned : —

1st. Appearance of epilepsy in animals born of parents which
had been rendered epileptic by an injury to the spinal cord.

2nd. Appearance of epilepsy also in animals born of parents
which had been rendered epileptic by section of the sciatic nerve.

3rd. A change in the shape of the ear in animals born of
parents in which such a change was the effect of a division
of the cervical sympathetic nerve.

4th. Partial closure of the eyelids in animals born of parents

pigment-cells from the lower side throughout life is due to the fact
that light does not act upon that side, for, when it is allowed to
act, pigment-cells appear. It seems to me the only reasonable con-
clusion from these facts is, that the disappearance of pigment-cells was
originally due to the absence of light, and that this change has now
become hereditary. The pigment-cells produced by the action of light
on the lower side are in all respects similar to those normally present
on the upper side of the fish. If the disappearance of the pigment-cells
were due entirely to a variation of the germ-plasm, no external influence
could cause them to reappear, and, on the other hand, if there were no
hereditary tendency, the colouration of the lower side of the flat-fish
when exposed would be rapid and complete." — Natural Science,
Oct. 1893.

I

Characters, Hereditary and Acquired. 105

in which that state of the eyelids had been caused either by
section of the cervical sympathetic nerve, or the removal of the
superior cervical ganglion.

5th. Exophthalmia in animals bom of parents in which an
injury to the restiform body had produced that protrusion of the
eyeball. This interesting fact I have witnessed a good many
times, and seen the transmission of the morbid state of the
eye continue through four generations. In these animals,
modified by heredity, the two eyes generally protruded, although
in the parents usually only one showed exophthalmia, the lesion
having been made in most cases only on one of the corpora
restiformia.

6th. Haematoma and dry gangrene of the ears in animals
born of parents in which these ear-alterations had been caused
by an injury to the restiform body near the nib of the calamus.

7th. Absence of two toes out of the three of the hind leg, and
sometimes of the three, in animals whose parents had eaten up
their hind-leg toes which had become anaesthetic from a section
of the sciatic nerve alone, or of that nerve and also of the crural.
Sometimes, instead of complete absence of the toes, only a part
of one or two or three was missing in the young, although in the
parent not only the toes but the whole foot were absent (partly
eaten off, partly destroyed by inflammation, ulceration, or
gangrene.)

8th. Appearance of various morbid states of the skin and
hair of the neck and face in animals bom of parents having had
similar alterations in the same parts, as effects of an injury to
the sciatic nerve.

These results ^ have been independently vouched
for by two of Brown-Sdquard's former assistants —
Dr. Dupuy, and the late Professor Westphal
Moreover, his results with regard to epilepsy have
been corroborated also by Obersteiner 2. I may

' For Professor Weismann's statement of and diacnssion of these
results see Essays, vol. i. p. 313.

^ Oesterreichische meJicinische Jahrbticher, i?75, 179^

io6 Darwin, and after Darwin,

observe, in passing, that this labour of testing Brown-
Sequard's statements is one which, in my opinion,
ought rather to have been undertaken, if not by
Weismann himself, at all events by some of his
followers. Both he and they are incessant in their
demand for evidence of the transmission of acquired
characters ; yet they have virtually ignored the fore-
going very remarkable statements However, be
this as it may, all that we have now to do is to
consider what the school of Weismann has had to say
with regard to these experiments on the grounds of
general reasoning which they have thus far been
satisfied to occupy.

In view of Obersteiner's corroboration of Brown-
Sequard s results touching the artificial production
and subsequent transmission of epilepsy, Weismann
accepts the facts, but, in order to save his theory
of heredity, he argues that the transmission may
be due to a traumatic introduction of " some unknown
microbe " wliich causes the epilepsy in the parent,
and, by invading the ova or spermatozoa as the
case may be. also produces epilepsy in the offspring.
Here, of course, there would be transmission of
epilepsy, but it would not be, technically speaking,
an hereditary transmission. The case would resemble
that of syphilis, where the sexual elements remain
unaffected as to their congenital endowments, although
they have been made the vehicles for conveying an
organic poison to the next generation.

Now it would seem that this suggestion is not,
on the face of it. a probable one. For '^some un-
known microbe" it indeed must be, which is always
on hand to enter a guinea-pig when certain operations

"N

f

CharacterSy Hereditary and Acquired. 107

are being performed on certain parts of the nervous
system, but yet will never enter when operations
of any kind are being effected elsewhere. Moreover,
Westphal has produced the epilepsy without any
incision^ by striking the heads of the animals with
a hammer ^ This latter fact, it appears to me,
entirely abolishes the intrinsically improbable sugges-
tion touching an unknown — and strangely eclectic —
microbe. However, it is but fair to state what
Weismann himself has made of this fact. The fol-
lowing is what he says : —

" It is obvious that the presence of microbes can have nothing
to do with such an attack, but the shock alone must have caused
morphological and functional changes in the centre of the pons
and medulla oblongata, identical with those produced by microbes
in the other cases. . . . Various stimuli might cause the nervous
centres concerned to deve'op the convulsive attack which,
together with its after- eflfects, we call epilepsy. In Westphal's
case, such a stimulus would be given by a powerful mechanical
shock (viz. blows on the head with a hammer) ; in Brown-
S^quard's experiments, by the penetration of microbes ^"

But from this passage it would seem that Weismann
has failed to notice that in *' Westphal's case," as
in " Brovvn-Sequard's experiments," the epilepsy was
transmitted to progeny. That epilepsy may be pro-
duced in guinea-pigs by a method which does not
involve any cutting (i.e. possibility of inoculation)
would no doubt tend to corroborate the suggestion
of microbes being concerned in its transmission when
it is produced by cutting, if in the former case there
were no such transmission. But as there is trans-
mission in both cases, the facts, so far as I can see,

' Loc. cit. * Essays, vol. i. p. 315.

io8 Darwin^ and after Darzmn,

entirely abolish the suggestion. For they prove that
even when epilepsy is produced in the parents under
circumstances which render "it obvious that the
presence of microbes can have nothing to do with
such an attack," the epileptiform condition is not-
withstanding transmitted to the progeny. What,
then, is gained by retaining the intrinsically im-
probable hypothesis of microbes to explain the fact
of transmission " in Brown-S^quard's experiments,"
when this very same fact is proved to occur without
the possibility of microbes " in WestphaPs case " ?

The only other objection with regard to the seeming
transmission of traumatic epilepsy which Weismann
has advanced is, that such epilepsy may be produced
by two or three very different operations — viz. division
of the sciatic nerves (one or both), an injury to the
spinal cord, and a stroke on the head. Does not
this show, it is asked, that the epileptic condition
of guinea-pigs is due to a generally unstable condition
of the whole nervous system and is not associated
with any particular part thereof? Well, supposing
that such is the case, what would it amount to?
I cannot see that it would in any way affect the
only question in debate — viz. What is the significance
of the fact that epilepsy is transmitted! Even if it
be but " a tendency," *' a disposition," or "a diathesis "
that is transmitted, it is none the less a case of
transmission, in fact quite as much so as if the patho-
logical state were dependent on the impaired condition
of any particular nerve-centre. For, it must be
observed, there can be no question that it is always
produced by an operation of some kind. If it were
ever to originate in guinea-pigs spontaneously, there

Characters J Hereditary and Acquired. 109

might be some room for supposing that its trans-
mission is due to a congenital tendency running
through the whole species — although even then it
would remain unaccountable, on the ultra-Darwinian
view, why this tendency should be congenitally
increased by means of an operation. But epilepsy
does not originate spontaneously in guinea-pigs ;
and therefore the criticism in question appears to me
irrelevant.

Again, it may be worth while to remark that
Brown-S^quard's experiments do not disprove the
possibility of its being some one nerve-centre which
IS concerned in all cases of traumatic epilepsy. And
this possibility becomes, I think, a probability in view
of Luciani's recent experiments on the dog. These
show that the epileptic condition can be produced
in this animal by injury to the cortical substance
of the hemispheres, and is then transmitted to pro-
geny^. These experiments, therefore, are of g^eat
interest — first, as showing that traumatic and trans-
missible epilepsy is not confined to guinea-pigs ;
and next, as indicating that the pathological state
in question is associated with the highest nerve-
centres, which may therefore well be affected by
injury to the lower centres, or even by section of a
large nerve trunk.

So much, then, with regard to the case of trans-
mitted epilepsy. But now it must be noted that,
even if Weismann's suggestion touching microbes
were fully adequate to meet this case, it would still
leave unaffected those of transmitted protrusion of
the eye, drooping of the eyelid, gangrene of the

' Les fonctions du Cerveau, p. loa.

no Darwin, and after Darwin,

ear, absence of toes, &c. In all these cases the facts,
as stated by Brown-S^quard, are plainly unamenable
to any explanation which would suppose them due
to microbes, or even to any general neurotic con-
dition induced by the operation. They are much too
definite, peculiar, and localized. Doubtless it is on
this account that the school of Weismann has not
seriously attempted to deal with them, but merely
recommends their repetition by other physiologists ^.
Certain criticisms, however, have been urged by
Weismann against the interpretation of Brown-
S^quard's facts as evidence in favour of the trans-
mission of acquired characters. It does not appear
to me that these criticisms present much weight ;
but it is only fair that we should here briefly consider
them ^.

First, with regard to Brown-S^quard's results other
than the production of transmitted epilepsy, Weismann
allows that the hypothesis of microbes can scarcely
apply. In order to meet these results, therefore, he
furnishes another suggestion— viz. that where the
nervous system has sustained " a great shock, " the
animals are very likely to bear " weak descendants,
and such as are readily affected by disease." Then, in
answer to the obvious consideration. " that this does
not explain why the offspring should suffer from the
same disease " as that which has been produced
in the parents, he adds — " But this does not appear
to have been by any means invariably the case.

* Essays^ vol. i. p. 82.

' As Weismann gives an excellent abstract of all the alleged facts up
to date {Essays, vol. i. pp. 319-324), it is needless for me to supply
another, further than that which I have already made from Brown-
Sequard.

I

Characters^ Hereditary and Acquired, iii

For ' Brown-S6quard himself says, the changes in
the eye of the offspring were of a very variable
nature, and were only occasionally exactly similar
to those observed in the parents.' "

Now, this does not appear to me a good com-
mentary. In the first place, it does not apply to
the other cases (such as the ears and the toes),
where the changes in the offspring, when they
occurred at all, were exactly similar to those observed
in the parents save that some of them occasionally
occurred on the opposite side, and frequently also on
both sides of the offspring. These subordinate facts,
however, will not be regarded by any physiologist
as making against the more ready interpretation of
the results as due to heredity. For a physiologist well
knows that homologous parts are apt to exhibit
conelated variability— and this especially where varia-
tions of a congenital kind are concerned, and also
where there is any reason to suppose that the nervous
system is involved. Moreover, even in the case of
the eye, it was always protrusion that was caused in
the parent and transmitted to the offspring as a result
of injuring the restiform bodies of the former ; while
it was always partial closure of the eyelids that was
caused and transmitted by section of the sympathetic
nerve, or removal of the cervical ganglia. Therefore, if
we call such effects '^ diseases," surely it was *' the same
disease " which in each case appeared in the parents
and reappeared in their offspring. Again, the " dis-
eases " were so peculiar, definite, and localized, that
I cannot see how they can be reasonably ascribed
to a general nervous ' shock." Why, for instance,
if this were the case, should a protruding eye never

112 Darzvin, mid after Darwin,

result from removal of the cervical ganglia, a droop-
ing eyelid from a puncture of the restiform body,
a toeless foot from either or both of these opera-
tions, and so on ? In view of such considerations I
cannot deem these suggestions touching " microbes "
and " diseases " as worthy of the distinguished
biologist from whom they emanate.

Secondly, Weismann asks — How can we suppose
these results to be instances of the transmission of
acquired characters, when from Brown-Sequard's own
statement of them it appears that the mutilation
itself was not inherited, but only its effects ? Neither
in the case of the sciatic nerve, the sympathetic nerve,
the cervical ganglion, nor the restiform bodies, was
there ever any trace of transmitted injury in the
corresponding parts of the offspring ; so that, if the
*■ diseases" from which they suffered be regarded as
hereditary, we have to suppose that a consequence
was in each case transmitted without the transmis-
sion of its cause, which is absurd. But I do not think
that this criticism can be deemed of much weight
by a physiologist as distinguished from a naturalist.
For nothing is more certain to a student of physiology,
in any of its branches, than that negative evidence, if
yielded by the microscope alone, is most- precarious.
Therefore it does not need a visible change in the
nervous system to be present, in order that the part
affected should be functionally weak or incapable :
pathology can show numberless cases of nerve-
disorder the " structural " causes of which neither
the scalpel nor the microscope can detect. So that,
if any peculiar form of nerve-disorder is transmitted
to progeny, and if it be certain that it has been

Characters y Hereditary and Acquired. 113

caused by injury to some particular part of the
nervous system, I cannot see that there is any
reason to doubt the transmission of a nervous lesion
merely on the ground that it is not visibly discernible.
Of course there may be other grounds for doubting
it ; but I am satisfied that this ground is untenable.
Besides, it must be remembered, as regards the
particular cases in question, that no one has thus far
investigated the histology of the matter by the greatly
improved methods which are now at our disposal.

I have now considered all the criticisms which
have been advanced against what may be called
the Lamarckian interpretation of Brown-Sequard's
results ; and I think it will be seen that they present
very little force — even if it can be seen that they
present any force at all. But it must be remembered
that this is a different thing from saying that the
Lamarckian interpretation is the true one. The
facts alleged are, without question, highly peculiar;
and, on this account alone, Brown-Sequard's inter-
pretation of them ought to be deemed provisional.
Hence, although as yet they have not encountered
any valid criticism from the side of ultra-Darwinian
theory, I do not agree with Darwin that, on the sup-
position of their truth as facts, they furnish positive
proof of the transmission of acquired characters.
Rather do I agree with Weismann that further in-
vestigation is needed in order to establish such an
important conclusion on the basis of so unusual a
class of facts. This further investigation, therefore,
I have undertaken, and will now state the results.

Although this work was begun over twenty years

II. I

114 Darwin^ and after Daj^wtn,

ago, and then yielded negative results, it was only
within the last decade that I resumed it more system-
atically, and under the tutelage of Brown-S^quard
himself. During the last two years, however, the
experiments have been so much interrupted by ill-
ness that even now the research is far from complete.
Therefore I will here confine myself to a tabular
statement of the results as far as they have hitherto
gone, on the understanding that, in so far as they
are negative or doubtful, I am not yet prepared to
announce them as final.

We may take Brown-S^quard's propositions in his
own order, as already given on page 104.

1st. Appearance of epilepsy in animals born of parents which
had been rendered epileptic by an injury to the spinal cord.

2nd. Appearance of epilepsy also in animals born of parents
which had been rendered epileptic by section of the sciatic nerve.

I did not repeat these experiments with a view
to producing epilepsy, because, as above stated, they
had been already and sufficiently corroborated in
this respect. But I repeated many times the experi-
ments of dividing the sciatic nerve for the purpose of
testing the statements made later on in paragraphs
7 and 8, and observed that it almost always had
the effect of producing epilepsy in the animal thus
operated upon — and this of a peculiar kind, the chief
characteristics of which may here be summarized.
The epileptiform habit does not supervene until
some considerable time after the operation ; it is
then transitory, lasting only for some weeks or
months. While the habit endures the fits never
occur spontaneously, but only as a result of irritating
a small area of skin behind the ear on the same side of

I

Character Sy Hereditary and Acquired, 115

the body as that on which the sciatic nerve had been
divided. Effectual irritation may be either mechan-
ical (such as g-entle pinching), electrical, or, though
less certainly, thermal. The area of skin in question,
soon after the epileptiform habit supervenes, and
during all the time that it lasts, swarms with lice
of the kind which infest guinea-pigs — i. e. the lice
congregate in this area, on account, I think, of the
animal being there insensitive, and therefore not
disturbing its parasites in that particular spot ; other-
wise it would presumably throw itself into fits
by scratching that spot. On removing the skin from
the area in question, no kind or degree of irritation
supplied to the subjacent tissue has any effect in pro-
ducing a fit. A fit never lasts for more than a very
few minutes, during which the animal is unconscious
and convulsed, though not with any great violence. The
epileptiform habit is but rarely transmitted to progeny.
Most of these observations are in accordance with
those previously made by Brown-Sequard, and also
by others who have repeated his experiments under
this heading. I can have no doubt that the injury
of the sciatic nerve or spinal cord produces a change
in some of the cerebral centres, and that it is
this change — whatever it is and in whatever part
of the brain it takes place — which causes the re-
markable phenomena in question.

3rd. A change in the shape of the ear in animals bom of
parents in which such a change was the effect of a division
of the cervical sympathetic nerve.

4th. Partial closure of the eyelids in animals born of parents
in which that state of the eyelids had been caused either by
section of the cervical sympathetic nerve, or the removal of the
superior cervical ganglion.

I 2

ii6 Darwin^ and after Darwin.

I have not succeeded in corroborating these results.
It must be added, however, that up to the time of
going to press my experiments on this, the easiest
branch of the research, have been too few fairly to
prove a negative.

5th. Exophthalmia in animals bom of parents in which an
injury to the restiform body had produced that protrusion of the
eyeball. ... In these animals, modified by heredity, the two
eyes generally protruded, although in the parents usually only
one showed exophthalmia, the lesion having been made in most
cases only on one of the corpora restiformia.

I have fully corroborated the statement that
injury to a particular spot of the restiform body is
quickly followed by a marked protrusion of the eye-
ball on the same side. I have also had many cases
in which some of the progeny of parents thus affected
have shown considerable protrusion of the eyeballs on
both sides, and this seemingly abnormal protrusion
has been occasionally transmitted to the next gener-
ation. Nevertheless, I am far from satisfied that
this latter fact is anything more than an accidental
coincidence. For I have never seen the so-called ex-
ophthalmia of progeny exhibited in so high a degree
as it occurs in the parents as an immediate result
of the operation, while, on examining any large
stock of normal guinea-pigs, there is found a con-
siderable amount of individual variation in regard
to prominence of eyeballs. Therefore, while not
denying that the obviously abnormal amount of
protrusion due to the operation may be inherited
in lesser degrees, and thus may be the cause of the
unusual degree of prominence which is sometimes
seen in the eyeballs of progeny born of exophthalmic

I

Characters, Hereditary and Acquired. 117

parents, I am unable to affirm so important a con-
clusion on the basis supplied by these experiments.

6th. Haematoma and dry gangrene of the ears in animals
bom of parents in which these ear-alterations had been caused
by an injury to the restiform body.

As regards the animals operated upon (i. e. the
parents), I find that the haematoma and dry gan-
grene may supervene either several weeks after the
operation, or at any subsequent time up to many
months. When it does supervene it usually affects
the upper parts of both ears, and may then eat its
way down until, in extreme cases, it has entirely
consumed two-thirds of the tissue of both ears.
As regards the progeny of animals thus affected,
in some cases, but by no means in all, a similarly
morbid state of the ears may arise apparently
at any time in the life-history of the individual.
But I have observed that in cases where two or
more individuals of the same litter develop this
diseased condition, they usually do so at about the
same time — even though this be many months after
birth, and therefore after the animals are fully grown.
But in progeny the morbid process never goes so
far as in the parents which have been operated
upon, and it almost always affects the middle thirds
of the ears. In order to illustrate these points, repro-
ductions of two of my photographs are appended.
They represent the consequences of the operation on
a male and a female guinea-pig. Among the progeny
of both these animals there were several in which
a portion of each ear was consumed by apparently the
same process, where, of course, there had been no
operation.

Fig. 1. — Reproduction of photographs from life of a male and female
guinea-pig, whose left restiform bodies had been injured by a scalpel
six months previously. The loss of tissue in both ears was due to
haematoma and dry gangrene, which, however, had ceased when the
photograph was taken.

Characters^ Hereditary and Acquired. 119

It should be observed that not only is a different part
of the ear affected in the progeny, but also a very
much less quaniity thereof. Naturally, therefore, the
hypothesis of heredity seems less probable than that
of mere coincidence on the one hand, or of transmitted
microbes on the other. But I hope to have fairly
excluded both these alternative explanations. For,
as regards merely accidental coincidence, I have
never seen this very peculiar morbid process in the ears,
or in any other parts, of guinea-pigs which have
neither themselves had their restiform bodies in-
jured, nor been born of parents thus mutilated. As
regards the hypothesis of microbes, I have tried to
inoculate the corresponding parts of the ears of
normal guinea-pigs, by first scarifying those parts
and then rubbing them with the diseased surfaces of
the ears of mutilated guinea-pigs ; but have not been
able in this way to communicate the disease.

It will be seen that the above results in large
measure corroborate the statements of Brown-
S^quard ; and it is only fair to add that he told me
they are the results which he had himself obtained
most frequently, but that he had al met with many
cases where the diseased condition of the ears in
parents affected the same parts in their progeny, and
also occurred in more equal degrees. Lastly, I should
like to remark, with regard to these experiments on
restiform bodies, and for the benefit of any one else who
may hereafter repeat them, that it will be necessary
for him to obtain precise information touching the
modus operandi. For it is only one very localized
spot in each restiform body which has to be injured in
order to produce any of the results in question.

120 Darwin^ and after Darwin

I myself lost two years of work on account of not
knowing this exact spot before going to Paris for the
purpose of seeing Brown-S^quard himself perform
the operation. I had in the preceding year seen one
of his assistants do so, but this gentleman had a much
more careless method, and one which in my hands
yielded uniformly negative results. The exact spot
in question in the restiform body is as far forwards as
it is possible to reach, and as far down in depth as is
compatible with not producing rotatory movements.

7th. Absence of two toes out of the three of the hind leg, and
sometimes of the three, in animals whose parents had eaten up
their hind-leg toes which had become anaesthetic from a section
of the sciatic nerve alone, or of that nerve and also of the crural.
Sometimes, instead of complete absence of the toes, only a part
of one or two or three was missing in the young, although in the
parent not only the toes but the whole foot were absent.

As I found that the results here described were
usually given by division of the sciatic nerve alone —
or, more correctly, by excision of a considerable por-
tion of the nerve, in order to prevent regeneration —
I did not also divide the crural. But, although I have
bred numerous litters from parents thus injured, there
has been no case of any inherited deficiency of toes.
My experiments in this connexion were carried on
through a series of six successive generations, so as to
produce, if possible, a cumulative effect. Nevertheless,
no effect of any kind was produced. On the other
hand, Brown-S6quard informed me that he had
observed this inherited absence of toes only in about
one or two per cent, of cases. Hence it is pos-
sible enough, that my experiments have not been
sufficiently numerous to furnish a case. It may be

Characters^ Hereditary and Acquired, 121

added that there is here no measurable possibility
of accidental coincidence (seeing that normal guinea-
pigs do not seem ever to produce young with any
deficiency of toes), while the only possibility of
mal-observation consists in some error with regard
to the isolation (or the tabulation) of parents and
progeny. Such an error, however, may easily arise.
For gangrene of the toes does not set in till some
considerable time after division of the sciatic nerve.
Hence, if the wound be healed before the gangrene
begins, and if any mistake has been made with re-
gard to the isolation (or tabulation) of the animal, it
becomes possible that the latter should be recorded
as an uninjured, instead of an injured, individual. On
this account one would like to be assured that
Brown-Sequard took the precaution of examining
the state of the sciatic nerve in those comparatively
few specimens which he alleges to have displayed
such exceedingly definite proof of the inheritance
of a mutilation. For it is needless to remark, after
what has been said in the preceding chapter on the
analogous case of epilepsy, that the proof would
not be regarded by any physiologist as displaced
by the fact that there is no observable deficiency
in the sciatic nerve of the toeless young.

8th. Appearance of various morbid states of the skin and
hair of the neck and face in animals bom of parents having had
similar alterations in the same parts, as effects of an injury to
the sciatic nerve.

I have not paid any attention to this paragraph,
because the facts which it alleges did not seem of
a sufficiently definite character to serve as a guide to
further experiment.

122 Darwifiy and after Darwin,

On the whole, then, as regards Brown-Sdquard's
experiments, it will be seen that I have not been
able to furnish any approach to a full corroboration.
But I must repeat that my own experiments have
not as yet been sufficiently numerous to justify
me in repudiating those of his statements which
I have not been able to verify.

The only other experimental results, where animals
are concerned, which seemed to tell on the side of
Lamarckianism. are those of Mr. Cunningham, already
alluded to. But, as the research is still in progress,
the school of Weismann may fairly say that it would
be premature to discuss its theoretical bearings.

Passing now from experiments on animals to
experiments on plants, I must again ask it to be
borne in mind, that here also no researches have
been published, which have had for their object the
testing of the question on which we are engaged.
As in the case of animals, therefore, so in that of
plants, we are dependent for any experimental results
bearing upon the subject to such as have been gained
incidentally during the course of investigations in
quite other directions.

Allusion has already been made, in my previous
essay, to De Vries' observations on the chromatophores
of algae passing from the ovum of the mother to
the daughter organism ; and we have seen that
even Weismann admits, " It appears possible that
a transmission of somatogenetic variation has here
occurred^." It will now be my object to show that
such variations appear to be sometimes transmitted

^ Examination of Weismannism, p. 83.

Characters, Hereditary and Acquired. 123

in the case of higher plants, and this under circum-
stances which carry much less equivocal evidence
of the inheritance of acquired characters, than can
be rendered by the much more simple organization
of an alga.

I have previously mentioned Hoffmann's experi-
ments on transplantation, the result of which was
to show that variations, directly induced by changed
conditions of life, were reproduced by seed ^. Weis-
mann, however, as we have seen, questions the
somatogenetic origin of these variations— attributing
the facts to a blastogenetic change produced in the
plants by a direct action of the changed conditions
upon the germ-plasm itself^. And he points out
that whether he is right or wrong in this inter-
pretation can only be settled by ascertaining whether
the observable somatic changes occur in the genera-
tion which is first exposed to the changed conditions
of life. If they do occur in the first generation, they
are somatogenetic changes, which afterwards re-act
on the substance of heredity, so as to transmit the
acquired peculiarities to progeny. But if they do
not occur till the second (or any later) generation,
they are presumably blastogenetic. Unfortunately
Hoffmann does not appear to have attended to
this point with sufficient care, but there are other
experiments of the same kind where the point has
been specially observed.

For instance, M. L. A. Carri^re * gathered seed from
the wild radish {Rapkanus Raphanistrum) in France,

* Examination of Weismannism, p. 93. ' Ibid. p. 153.

• Origine des Plantes Domestiques^ dinumtrie par la culture du Radis
Sauvage (Paris, 1869';.

124 Darwin J and after Darwin,

and sowed one lot in the light dry soil near the
Museum of Natural History in Paris, while another
lot was sown by him at the same time in heavy
soil elsewhere. His object was to ascertain whether
he could produce a good cultivated radish by
methodical selection ; and this he did. in a wonder-
fully rapid manner, during the course of a very few
generations. But the point for us is, that from the
first the plants grown in the light soil of Paris
presented sundry marked differences from those
grown in the heavy soil of the country ; and that
these points of difference had nothing to do with
the variations on which his artificial selection was
brought to bear. For while his artificial selection
was directed to increasing the size of the "root,"
the differences in question had reference to its form
and colour. In Paris an elongated form prevailed,
which presented either a white or a rose colour : in
the country the form was more rounded, and the
colour violet, dark brown, or " almost black." Now,
as these differences were strongly apparent in the
first generation, and were not afterwards made the
subject of selection, both in' origin and development
they must have been due to " climatic " influences
acting on the somatic tissues. And although the author
does not appear to have tested their hereditary char-
acters by afterwards sowing the seed from the Paris
variety in the country, or vice versa, we may
fairly conclude that these changes must have been
hereditary — ist, from the fact of their intensification
in the course of the five sequent generations over
which the experiment extended, and, 2nd, from the
very analogous results which were similarly obtained

Characters^ Hereditary and Acquired. 125

in the following case with another genus, where
both the somatogenetic and the hereditary characters
of the change were carefully and specially observed.
This case is as follows.

The late Professor James Buckman, F.R.S., saved
some seed from wild parsnips [P. sativa) in the
summer of 1847, and sowed under changed conditions
of life in the spring of 1848. The plants grown
from these wild seeds were for the most part like
wild plants ; but some of them had " already
(i. e. in the autumn of 1848) the light green and
smooth aspect devoid of hairs which is peculiar to
the cultivated plant ; and among the latter there
were a few with longer leaves and broader divisions
of leaf-lobes than the rest — the leaves, too, all grow-
ing systematically round one central bud. The roots
of the plant when taken up were observed to be
for the most part more fleshy than those of wild
examples ^."

Professor Buckman then proceeds to describe how
he selected the best samples for cultivation in
succeeding generations, till eventually the variety
which he called " The Student " was produced, and
which Messrs. Sutton still regard as the best variety
in their catalogue. That is to say, it has come
true to seed for the last forty years; and although
such great excellence and stability are doubtless in
chief part due to the subsequent process of selec-
tion by Professor Buckman in the years 1848-1850,
this does not affect the point with which we are
here concerned — namely, that the somatogenetic
changes of the plants in the first generation were

' Journl. Agric. Soc, 1848.

126 Darwin, and after Darwin.

transmitted by seed to the second generation,
and thus furnished Professor Buckman with the
material for his subsequent process of selection.
And the changes in question were not merely ot
a very definite character, but also of what may be
termed a very local character — affecting only par-
ticular tissues of the soma, and therefore expressive
of a high degree of representation on the part of the
subsequently developed seed, by which they were
faithfully reproduced in the next generation.

Here is another case. M. Lesage examined the
tissues of a large number of plants growing both
near to, and remote from, the sea. He suspected
that the characteristic fleshiness, &c. of seaside plants
was due to the influence of sea-salt ; and proved that
such was the case by causing the characters to
occur in inland plants as a result of watering them
with salt-water. Then he adds : —

**J'ai reussi surtout pour le Lepidium sativum cultiv^ en
1888 ; j'ai obtenu pour la meme plante des resultats plus nets
encore dans la culture de 1889, entreprise en semant les graines
r^coltees avec soin des pots de Tannic precedente et traitdes
exactement de la meme fa^on^ "

Here, it will be observed, there was no selec-
tion ; and therefore the increased hereditary effect
in the second generation must apparently be ascribed
to a continuance of influence exercised by somatic
tissues on germinal elements ; for at the time when
the changes were produced no seed had been formed.
In other words, the accumulated change, like the
initial change, would seem to have been exclusively
of somatogenetic origin ; and yet it so influenced the

' Rev. Gen. dt Bot. torn. ii. p. 64.

Characters J Hereditary and Acquired, 127

qualities of the seed (as this was afterwards formed),
that the augmented changes were transmitted to the
next generation, part for part, as the lesser changes had
occurred in the preceding generation. "This experi-
ment, therefore, like Professor Buckman's, shows that
the alteration of the tissues was carried on in the
second generation from the point gained in the first.
In both cases no germ-plasm (in the germ-cells)
existed at the time during which the alterations
arose, as they were confined to the vegetative system;
and in the case of the parsnips and carrots, being
biennials no germ-cells are produced till the second
year has arrived ^."

Once more, Professor Bailey remarks: —

"Squashes often show remarkable differences when grown
upon different soils ; and these differences can sometimes be per-
petuated for a time by seeds. The writer has produced, from
the same parent, squashes so dissimilar, through the simple
agency of a change of soil in one season, that they might readily
be taken for distinct varieties. Peas are known to vary in the
same manner. The seeds of a row of peas of the same kind,
last year gave the writer marked variations due to differences

of soil Pea-growers characterize soils as 'good' and

'viney.' Upon the latter sort the plants run to vine at the
expense of the fruit, and their offspring for two or three
generations have the same tendency *.'*

I think these several cases are enough to show
that, while the Weismannian assumption as to the
seeming transmission of somatogenetic characters
being restricted to the lowest kinds of plants is

* I am indebted to the Rev. G. Henslow for the references to
these cases. This and the passages which follow are quoted from his
letters to me.

* Gardener's Chronicle^ May 31, 1890, p. 677.

128 Darwin^ and after Darwin,

purely gratuitous, there is no small amount of
evidence to the contrary — or evidence which seems
to prove that a similar transmission occurs likewise
in the higher plants. And no doubt many additional
cases might be advanced by any one who is well
read in the literature of economic botany.

It appears to me that the only answer to such cases
would be furnished by supposing that the heredi-
tary changes are due to an alteration of the residual
" germ-plasm " in the wild seed, when this is first
exposed to the changed conditions of life, due to
its growth in a strange kind of soil— e. g. while ger-
minating in an unusual kind of earth for producing the
first generation. But this would be going a long
way to save an hypothesis. In case, however, it
should now be suggested, I may remark that it
would be negatived by the following facts ^

In the first place, an endless number of cases might
be quoted where somatogenetic changes thus pro-
duced by changed conditions of life are not hereditary.
Therefore, in all these cases it is certainly not the
" germ-plasm " that is affected. In other words, there
can be no question that somatogenetic changes of the
kinds above mentioned do very readily admit of being
produced in the first generation by changes of soil,
altitude, &c. And that somatogenetic changes thus
produced should not always — or even generally —
prove themselves to be hereditary from the first
moment of their occurrence^ is no more than any theory

' Since the above was written Professor Weismann has advanced, in
7X* Germ-plasm, a suggestion very similar to this. It is sufficient here
to remark, that nearly all the facts and considerations which ensue in
the present chapter are applicable to his suggestion, the essence of which
is anticipated in the above paragraph.

Characters, Hereditary and Acquired, 129

of heredity would expect. Indeed, looking to the
known potency of reversion, the wonder is that in any
case such changes should become hereditary in a single
generation. On the other hand, there is no reason to
imagine that the hypothetical germ-plasm— howsoever
unstable we may suppose it to be — can admit of being
directly affected by a change of soil in a single
generation. For, on this view, it must presumably be
chiefly affected during the short time that the seed is
germinating ; and during that time the changed con-
ditions can scarcely be conceived as having any points
of attack, so to speak, upon the residual germ-plasm.
There arc no roots on which the change of soil can
make itself perceptible, nor any stem and leaves on
which the change of atmosphere can operate. Yet the
changed conditions may produce hereditary modifica-
tions in any parts of the plant, which are not only
precisely analogous to non-hereditary changes similarly
produced in the somatic tissues of innumerable other
plants, but are always of precisely the same kind in
the same lot of plants that are affected. When all the
radishes grown from wild seed \\\ Paris, for instance,
varied in the direction of rotundity and dark colour,
while those grown in the country presented the opposite
characters, we can well understand the facts as due
to an entire season's action upon the whole of the
growing plant, with the result that all the changes
produced in each set of plants were similar — just as
in the cases where similarly •' climatic " modifications
are not hereditary, and therefore unquestionably due
to changed conditions acting on roots, stems, leaves,
or flowers, as the case may be. On the other hand,
it is not thus intelligible that during the short

II. K

130 Darwifiy and after Darwin,

time of germination the changed conditions should
effect a re-shuffling (or any other modification) of
the " germ-plasm " in the seeds — and this in such
a manner that the effect on the residual germ-plasm
reserved for future generations is precisely similar to
that produced on the somatic tissues of the developing
embryo.

In the second place, as we have seen, in some of
the foregoing cases the changes were produced
months — and even years — before the seeds of the first
germination were formed. Therefore the hereditary
effect, if subsequent to the period of embryonic ger-
mination, must have been produced on germ-plasm
as this occurs diffused through the somatic tissues.
But, if so, we shall have to suppose that such germ-
plasm is afterwards gathered in the seeds when these
are subsequently formed. This supposition, however,
would be radically opposed to Weismann's theory of
heredity : nor do I know of any other theory with
which it would be reconcilable, save such as entertain
the possibility of the Lamarckian factors.

Lastly, in the third place, I deem the following
considerations of the highest importance : —

"As other instances in which peculiar structures are now
hereditary may be mentioned aquatic plants and those producing
subterraneous stems. Whether they be dicotyledons or mono-
cotyledons, there is a fundamental agreement in the anatomy
of the roots and stem of aquatic plants, and, in many cases, of
the leaves as well. Such has hitherto been attributed to the
aquatic habit. The inference or deduction was, of course, based
upon innumerable coincidences ; the water being supposed to
be the direct cause of the degenerate structures, which are
hereditary and characteristic of such plants in the wild state.
M. Costantin has, however, verified this deduction, by making

Character Sy Hereditary and Acquired, 131

terrestrial and aerial stems to grow underground and in water :
the structures at once began to assume the subterranean or
aquatic type, as the case might be ; and, conversely, aquatic
plants made to grow upon land at once began to assume the
terrestrial type of structure, while analogous results followed
changes from a subterranean to an aerial position, and vice

This is also quoted from the Rev. Prof. Henslow's
letters to me, and the important point in it is, that
the great changes in question are proved to be of
a purely " somatogenetic " kind ; for they occurred " at
once '' in the ready-grown plants when the organs
concerned were exposed to the change from aquatic
to terrestrial life, or vice versa — and also from a sub-
terranean to an aerial position, or vice versa. Con-
sequently, even the abstract possibility of the changed
conditions of life having operated on the seed is here
excluded. Yet the changes are of precisely the same
kind as are now hereditary in the wild species. It
thus appears undeniable that all these remarkable and
uniform changes must originally have been somato-
genetic changes ; yet they have now become blasto-
genetic. This much, I say, seems Undeniable ; and
therefore it goes a long way to prove that the non-
blastogenetic character of the changes has been due
to their originally somatogenetic character. For, if
not, how did natural selection ever get an opportunity
of making any of them blastogenetic, when every
individual plant has always presented them as already
given somatogenetically? This last consideration
appears in no small measure to justify the opinion of
Mr. Henslow, who concludes — "These experiments
prove, not only that the influence of the environment

K 1

132 Darwin^ and after Darwin,

is at once felt by the organ ; but that it is indubitably
the cause of the now specific and hereditary traits
peculiar to normally aquatic, subterranean, and
aerial stems, or roots ^."

He continues to furnish other instances in the same
line of proof — such as the distinctive * habits" of
insectivorous, parasitic, and climbing plants ; the
difference in structure between the upper and under
sides of horizontal leaves, &c " For here, as in all
organs, we discover by experiment how easily the
anatomy of plants can be affected by their environ-
ment ; and that, as long as the latter is constant, so are
the characters of the plants constant and hereditary."

* It also serves to show that Weismann's newer doctrine of similar
" detenninants " occurring both in the germ and in the somatic tissues
is a doctrine which cannot be applied to rebut this evidence of the
transmission of acquired characters in plants. Therefore even its
hypothetical validity as applied by him to explain the seasonal variation
of butterflies is rendered in a high degree dubious.

[The following letter, contributed by Dr. Hill to Nature, vol. 1. p. 617,
may here be quoted. C. LI. M.

** It may be of interest to your readers to know that two guinea-pigs
were bom at Oxford a day or two before the death Dr. Romanes, both
of which exhibited a well-marked droop of the left upper eye-lid. These
guinea-pigs were the offspring of a male and a female guinea-pig in both
of which I had produced for Dr. Romanes, some months earlier, a droop
of the left upper eyelid by division of the left cervical sympathetic nerve.
This result is a corroboration of the series of Brown-Sequard's experi-
ments on the inheritance of acquired characteristics. A very large series
of such experiments are of course needed to eliminate all sources of error,
but this I unfortunately cannot carry out at present, owing to the need of
a special farm in the country, for the proper care and breeding of the
animals. — Leonard Hill.

"Physiological Laboratory, Univ. Coll. London, Oct. 18, 1894."]

CHAPTER V.

Characters as Hereditary and Acquired
(continued).

(A. and B.)

Direct and Indirect Evidence in favour of the Non-
inheritance of Acquired Characters ^.

The strongest argument in favour of " continuity '
is that based upon the immense difference between
congenital and acquired characters in respect of
heritability. For that there is a great difference
in this respect is a matter of undeniable fact. And
it is obvious that this difference, the importance of
which must be allowed its full weight, is just what
we should expect on the theory of the continuity of
the germ-plasm, as opposed to that of pangenesis.
Indeed it may be said that the difference in question,
while it constitutes important evidence in favour of
the former theory, is a diffictdty in the way of the
latter. But here two or three considerations must be
borne in mind.

In the first place, this fact has long been one which
has met with wide recognition and now constitutes
the main ground on which the theory of continuity
^ '^Su note appended to Preface. C. LI. M.]

134 Darwin^ and after Darwin.

stands. That is to say, it was the previous know-
ledge of this contrast between congenital and acquired
characters which led to the formulation of a theory of
continuity by Mr. Galton, and to its subsequent
development by Prof Weismann.

But, in the second place, there is a wide difference
between the certainty of this fact and that of the
theory based upon it. The certain fact is, that
a great distinction in respect of heritability is
observable between congenital and acquired char-
acters. The theory, as formulated by Weismann, is
that the distinction is not only great but absolute, or,
in other words, that in no case and in no degree
can any acquired character be ever inherited. This
hypothesis, it will be observed, goes far beyond the
observed fact, for it is obviously possible that, not-
withstanding this great difference in regard to herita-
bility between congenital and acquired characters,
the latter may nevertheless, sometimes and in some
degree, be inherited, however much difficulty we may
experience in observing these lesser phenomena in
presence of the greater. The Weismannian hypo-
thesis of absolute continuity is one thing, while the
observed fact of at least a high relative degree of
continuity is quite another thing. And it is neces-
sary to be emphatic on this point, since some of the
reviewers of my Examination of W eismannism con-
found these two things. Being apparently under the
impression that it was reserved for Weismann to
perceive the fact of there being a great difference
between the heritability of congenital and acquired
characters they deem it inconsistent in me to
acknowledge this fact while at the same time

Characters^ Hereditary and Acquired. 135

questioning the hypothetical basis of his funda-
mental postulate touching the absolute continuity of
germ-plasm. It is one merit of Galton's theory, as
against Weismann's, that it does not dogmatically
exclude the possible interruption of continuity on
some occasions and in some degree. Herein, indeed,
would seem to lie the central core of the whole
question in dispute. For it is certain and has long
been known that individually acquired characters
are at all events much less heritable than are long-
inherited or congenital ones. But Lamarckian theory
supposes that congenital characters were in some
cases originally acquired, and that what are now
blastogenetic characters were in some cases at first
somatogenetic and have become blastogenetic only
in virtue of sufficiently long inheritance. Since
Darwin's time, however, evolutionists (even of the
so-called Lamarckian type) have supposed that
natural selection greatly assists this process of deter-
mining which somatogenetic characters shall become
congenital or blastogenetic. Hence all schools of
evolutionists are, and have long been, agreed in
regarding the continuity principle as true in the main.
No evolutionist would at any time have propounded
the view that one generation depends for all its
characters on those acquired by its immediate ances-
tors, for this would merely be to unsay the theory of
Evolution itself, as well as to deny the patent facts
of heredity as shown, for example, in atavism. At
most only some fraction of a per ce7it. could be
supposed to do so. But Weismann's contention is
that this principle is not only true in the main, but
absolutely true ; so that natural selection becomes all

136 DarwiUy and after Darwin.

in all or not at all. Unless Weismannism be regarded
as this doctrine of absolutism it permits no basis for
his attempted theory of evolution.

And, whatever may be said to the contrary by the
more enthusiastic followers of Prof. Weismann. I must
insist that there is the widest possible difference
between the truly scientific question of fact which is
assumed by Weismann as answered (the base-line of
the diagram on p. 43), and the elaborate structure
of deductive reasoning which he has reared on this
assumption (the Y-like structure). Even if the
assumption should ever admit of inductive proof, the
almost bewildering edifice of deductive reasoning
which he has built upon it would still appear to me to
present extremely little value of a scientific kind. In-
teresting though it may be as a monument of ingenious
speculation hitherto unique in the history of science,
the mere flimsiness of its material must always pre-
vent its far-reaching conclusions from being worthy
of serious attention from a biological point of view.
But having already attempted to show fully in my
Exammaiion this great distinction between the
scientific importance of the question which lies at the
base of " Weismannism," and that of the system which
he has constructed on his assumed answer thereto,
I need not now say anything further with regard to it.

Again, on the present occasion and in this connexion
I should like to dissipate a misunderstanding into
which some of the reviewers of the work just men-
tioned have fallen. They appear to have concluded
that because I have criticized unfavourably a con-
siderable number of Weismann's theories, I have
shown myself hostile to his entire system. Such,

Characters^ Hereditary and Acquired. 137

however, is by no means the case ; and the mis-
understanding can only be accounted for by sup-
posing that the strongly partisan spirit which these
critics display on the side of neo-Darwinism has
rendered them incapable of appreciating any attempt
at impartial — or even so much as independent —
criticism. At all events, it is a matter of fact that
throughout the work in question I have been par-
ticularly careful to avoid this misunderstanding as to
my own position. Over and over again it is there
stated that,* far from having any objection to the
principle of " Continuity " as represented in the base-
line of the above diagram. I have been convinced
of its truth ever since reading Mr. Galton's Theory
of Heredity in 1875. All the "hard words" which
I have written against Weismann's system of theories
have reference to those parts of it which go to con-
stitute the Y-like structure of the diagram.

It is, however, desirable to recur to another point,
and one which I hope will be borne in mind through-
out the following discussion. It has already been
stated, a few pages back, that the doctrine of con-
tinuity admits of being held in two very different
significations. It may be held as absolute, or as
relative. In the former case we have the Weis-
mannian doctrine of germ-plasm : the substance of
heredity is taken to be a substance per se, which
has always occupied a separate " sphere " of its own,
without any contact with that of somatoplasm further
than is required for its lodgement and nutrition ;
hence it can never have been in any degree modi-
fied as to its hereditary qualities by use-inheritance
or any other kind of somatogenetic change ; it has

138 Darwin, and after Darwin,

been absolutely continuous "since the first origin of
life." On the other hand, the doctrine of continuity
may be held in the widely different sense in which
it has been presented by Galton's theory of Stirp.
Here the doctrine is, that while for the most part
the phenomena of heredity are due to the continuity
of the substance of heredity through numberless
generations, this substance (*• Stirp ") is nevertheless
not absolutely continuous, but may admit, in small
though cumulative degrees, of modification by use-
inheritance and other factors of the Lamarckian kind.
Now this all -important distinction between these two
theories of continuity has been fully explained and
thoroughly discussed in my Examination ; therefore
I will not here repeat myself further than to make
the following remarks.

The Weismannian doctrine of continuity as abso-
lute (base-line of the diagram) is necessary for the
vast edifice of theories which he has raised upon it
(the Y), first as to the minute nature and exact
composition of the substance of heredity itself
(" Germ-plasm "), next as to the precise mechanism
of its action in producing the visible phenomena of
heredity, variation, and all allied phenomena, and,
lastly, the elaborate and ever-changing theory of
organic evolution which is either founded on or
interwoven with this vast system of hypothetic
speculation. Galton's doctrine of continuity, on
the other hand, is a " Theory of Heredity," and
a theory of heredity alone. It does not meddle
with any other matters whatsoever, and rigidly
3,voids all speculation further than is necessary for
the bare statement and inductive support of the

Characters, Hereditary and Acquired, 139

doctrine in question. Hence, it would appear that
this, the only important respect wherein the doc-
trine of continuity as held by Galton differs from
the doctrine as held by Weismann, arises from the
necessity under which the latter finds himself of
postulating absolute continuity as a logical basis
for his deductive theory of the precise mechanism
of heredity on the one hand, and of his similarly
deductive theory of evolution on the other. So far
as the doctrine of continuity is itself concerned
(i.e the question of the inheritance of acquired
characters), there is certainly no more inductive
reason for supposing the continuity absolute " since
the first origin of life/' than there is for supposing
it to be more or less susceptible of interruption by
the Lamarckian factors. In other words, but for
the sake of constructing a speculative foundation
for the support of his further theories as to *' the
architecture of germ-plasm " and the factors of
organic evolution, there is no reason why Weismann
should maintain the absolute separation of the
" sphere ' of germ-plasm from that of somatoplasm.
On the contrary, he has no reason for concluding
against even a considerable and a frequent amount
of cutting, or overlapping, on the part of these two
spheres.

But although this seems to me sufficiently obvious,
as 1 have shown at greater length in the Examination
of Weismannism, it must not be understood that
I hold that there is room for any large amount of
such overlapping. On the contrary, it appears to me
as certain as anything can well be that the amount
of such overlapping from one generation to another,

140 Darwin J and after Darwin.

if It ever occur at all, must be exceedingly small,
so that, if we have regard to only a few sequent
generations, the effects of use- inheritance, and La-
marckian factors are, at all events as a rule,
demonstrably imperceptible. But this fact does not
constitute any evidence — as Weismann and his
followers seem to suppose — against a possibly im-
portant influence being exercised by the Lamarckian
factors, in the way of gradual increments through
a long series of generations. It has long been well
known that acquired characters are at best far less
fully and far less certainly inherited than are con-
genital ones. And this fact is of itself sufficient
to prove the doctrine of continuity to the extent
that even the Lamarckian is rationally bound to
concede. But the fact yields no proof— scarcely
indeed so much as a presumption — in favour of the
doctrine of continuity as absolute. For it is suffi-
ciently obvious that the adaptive work of heredity
could not be carried on at all if there had to be
a discontinuity in the substance of heredity at every
generation, or even after any very large number of
generations.

Little more need be said concerning the argu-
ments which fall under the headings A and B. The
Indirect evidence is considered in Appendix I of the
Examination of Weismannism ; while the Direct
evidence is considered in the text of that work in
treating of Professor Weismann's researches on the
Hydromedusae (pp. 71-76).

The facts of karyokinesis are generally claimed
by the school of Weismann as making exclusively
in favour of continuity as absolute. But this is

Characters, Hereditary arid Acquired, 141

a partisan view to take. In any impartial survey
it should be seen that while the facts are fairly
interpretable on Weismann's theory, they are by
no means proof thereof. For any other theory of
Heredity must suppose the material of heredity to
be of a kind more or less specialized, and the
mechanism of heredity extremely precise and well
ordered. And this is all that the facts of karyo-
kinesis prove. Granting that they prove continuity,
they cannot be held to prove that continuity to
be absolute. In other words, the facts are by no
means incompatible with even a large amount of
commerce between germ-plasm and somato-plasm, or
a frequent transmission of acquired characters.

Again, Weismann's theory, that the somatic and
the germ-plasm determinants may be similarly and
simultaneously modified by external conditions may
be extended much further than he has used it
himself, so as to exclude, or at any rate invalidate,
all evidence in favour of Lamarckianism, other than
the inheritance of the effects of use and disuse. All
evidence from apparently inherited effects produced
by change of external conditions is thus virtually
put out of court, leaving only evidence from the
apparently inherited effects of functionally produced
modifications. And this line of evidence is invalidated
by Panmixia. Hence there remain only the arguments
from selective value and co-adaptation. Weismann
meets these by adducing the case of neuter insects,
which have been already considered at sufficient
length.

142 Darwin, and after Darwin.

(C.)

Experimental Evidence as to the Non-inheritance
of Acquired Characters,

Let us now proceed to the experimental evidence
which has been adduced on the side of Weismannism.

Taking this evidence in order of date, we have
first to mention that on which the school of
Weismann has hitherto been satisfied almost ex-
clusively to rely. This is the line of negative
evidence, or the seeming absence of any experimental
demonstration of the inheritance of acquired char-
acters. This kind of evidence, however, presents
much less cogency than is usually supposed. And
it has been shown in the last chapter that the
amount of experimental evidence in favour of the
transmission of acquired characters is more con-
siderable than the school of Weismann seems to be
aware — especially in the vegetable kingdom. I do
not think that this negative line of evidence presents
much weight; and, to show that I am not biassed
in forming this judgement, I may here state that few
have more reason than myself for appreciating the
weight of such evidence. For, as already stated,
when first led to doubt the Lamarckian factors, now-
more than twenty years ago, I undertook a research
upon the whole question — only a part of which was
devoted to testing the particular case of Brown-
Sequard's statements, with the result recorded in the
preceding chapter. As this research yielded negative
results in all its divisions - and, not only in the matter
of Brown-S^quard's statements — I have not hitherto

I

Characters y Hereditary and Acquired, 143

published a word upon the subject. But it now
seems worth while to do so, and for the following
reasons.

First, as just observed, a brief account of my old
experiences in this field will serve to show what good
reason I have for feeling the weight of such negative
evidence in favour of Continuity as arises from failure
to produce any good experimental evidence to the
contrary. In the second place, now that the question
has become one of world-wide interest, it would seem
that even negative results deserve to be published
for whatever they may be worth on the side of Neo-
Darwinism. Lastly, in the third place, although the
research yielded negative results in my hands, it is
perhaps not undesirable to state the nature of it,
if only to furnish suggestions to other physiologists,
in whose hands the experiments — especially in these
days of antiseptics — may lead to a different termina-
tion. Altogether I made thousands of experiments
in graft-hydridization (comprising bines, bulbs of
various kinds, buds, and tubers) ; but with uniformly
negative results. With animals I tried a number of
experiments in grafting characteristic congenital tissues
from one variety on another — such as the combs of
Spanish cocks upon the heads of Hamburgs ; also,
in mice and rats, the grafting together of different
varieties ; and, in rabbits and bitches, the transplant-
ation of ovaries of newly-born individuals belonging
to different well-marked breeds. This latter experi-
ment seems to be one which, if successfully performed
(so that the transplanted ovaries would form their
attachment in a young bitch puppy and subsequently
yield progeny to a dog of the same breed as herself)

144 Darwin, and after Darwin.

would furnish a crucial test as to the inheritance or
non-inheritance of acquired characters. Therefore
I devoted to it a large share of my attention, and
tried the experiment in several different ways. But
I was never able to get the foreign ovary — or even any
portion thereof — to graft. Eventually the passing of
the Vivisection Act caused me to abandon the whole
research as far as animals were concerned — a research,
indeed, of which I had become heartily tired, since in
no one instance did I obtain any adhesion. During
the last few years, however, I have returned to these
experiments under a licence, and with antiseptic
precautions, but with a similar want of success.
Perhaps this prolonged and uniformly fruitless expe-
rience may now have the effect of saving the time of
other physiologists, by warning them off the roads
where there seems to be no thoroughfare. On the
other hand, it may possibly lead some one else to
try some variation in the method, or in the material,
which has not occurred to me. In particular, I am
not without hope that the transplantation of ovaries
in very young animals may eventually prove to be
physiologically possible; and, if so, that the whole
issue as between the rival theories of heredity will
be settled by the result of a single experiment.
Possibly some of the invertebrata will be found to
furnish the suitable material, although I have been
unable to think of any of these which present
sufficiently well-marked varieties for the purpose.
But, pending the successful accomplishment of this
particular experiment in the grafting of any animal
tissue, I think it would be clearly unjustifiable to
conclude against the Lamarckian factors on the

I

Characters^ Hereditary and Acquired, 145

ground of any other experiments yielding negative
results in but one generation or even in a large
number of sequent generations.

For instance, the latter consideration applies to the
negative results of Mr. Francis Galton's celebrated
Experimettts in Pangenesis K These consisted in
transfusing the blood of one variety of rabbit into
the veins of both sexes of another, and then allowing
the latter to breed together : in no case was there any
appearance in the progeny of characters distinctive
of the variety from which the transfused blood was
derived. But, as Mr. Galton himself subsequently
allowed, this negative result constitutes no disproof
of pangenesis, seeing that only a portion of the
parents' blood was replaced ; that this portion, even
if charged with "gemmules," would contain but
a very small number of these hypothetical bodies,
compared with those contained in all the tissues of
the parents ; and that even this small proportional
number would presumably be soon overwhelmed by
those contained in blood newly-made by the parents.
Nevertheless the experiment was unquestionably
worth trying, on the chance of its yielding a positive
result ; for, in this event, the question at issue
would have been closed. Accordingly I repeated
these experiments (with the kind help of Professor
Schafer), but with slight differences in the method,
designed to give pangenesis a better chance, so to
speak.

Thus I chose wild rabbits to supply the blood,
and Himalayan to receive it — the former being the
ancestral type (and therefore giving reversion an
* Proc. R. S. 1 871.

II L

146 DarwiHy and after Darwin,

opportunity of coming into play), while the latter,
although a product of domestication, is a remarkably
constant variety, and one which differs very much
in size and colour from the parent species. Again,
instead of a single transfusion, there were several
transfusions performed at different times. Moreover,
we did not merely allow the blood of one rabbit
to flow into the veins of the other (whereby little
more than half the blood could be substituted);
but sacrificed three wild rabbits for refilling the
vascular system of each tame one on each occasion.
Even as thus improved, however, the experiment
yielded only negative results, which, therefore, we
never published.

Subsequently I found that all this labour, both
on Mr. Galton's part and our own, was simply
thrown away — not because it yielded only negative
results, but because it did not serve as a crucial
experiment at all. The material chosen was un-
serviceable for the purpose, inasmuch as rabbits,
even when crossed in the ordinary way, never throw
intermediate characters. Needless to say, had I been
aware of this fact before, I should never have re-
peated Mr. Galton's experiments— nor, indeed, would
he have originally performed them had he been aware
of it. So all this work goes for nothing. The research
must begin all over again with some other animals,
the varieties of which when crossed do throw inter-
mediate characters.

Therefore I have this year made arrangements
for again repeating the experiments in question —
only, instead of rabbits, using well-marked varieties
of dogs. A renewed attack of illness, however, has

Characters^ Hereditary and Acquired. 147

necessitated the surrender of this research to other
hands, with a consequent delay in its commencement.
My ignorance of the unfortunate peculiarity dis-
played by rabbits in not throwing intermediate
characters has led to a further waste of time in
another line of experiment. On finding that mam-
malian ovaries did not admit of being grafted, it
seemed to me that the next best thing to try would be
the transplantation of fertilized ova from one variety
to another, for the purpose of ascertaining whether,
if a parturition should take place under such circum-
stances, gestation by the uterine mother would affect
the characters of the ovum derived from the ovarian
mother — she, of course, having been fertilized by a
male of her own variety. Of course it was necessary
that both the mothers should be in season at about the
same time, and therefore I again chose rabbits, seeing
that in the breeding season they are virtually in a
chronic state of "heat." I selected Himalayans and
Belgian hares, because they are well-marked varieties,
breed true, and in respect of colour are very different
from one another. It so happened that while I was
at work upon this experiment, it was also being tried,
unknown to me, by Messrs. Heape and Buckley who,
curiously enough, employed exactly the same material.
They were the first to obtain a successful result.
Two fertilized ova of the Angora breed having been
introduced into the fallopian tube of a Belgian hare,
developed there in due course, and gave rise to two
Angora rabbits in no way modified by their Belgian
hare gestation ^

^ Proc. R. S. 1890, vol. xlviii. p. 457. It should be stated that the
authors do not here concern themselves with any theory of heredity.

L 2

148 Darwin, and after Darwin.

But. interesting and suggestive as this experiment
is in other connexions, it is clearly without sig-
nificance in the present one, for the reason already
stated. It will have to be tried on well-marked varieties
of other species of animals, which are known to throw
intermediate characters. Even, however, if it should
then yield a similarly negative result, the fact would
not tell against the inheritance of acquired characters ;
seeing that an ovum by the time it is ripe is a finished
product, and therefore not to be expected, on any
theory of heredity, to be influenced as to its hereditary
potentialities by the mere process of gestation. On
the other hand, if it should prove that it does admit
of being thus affected, so that against all reasonable
expectation the young animal presents any of the
hereditary characters of its uterine mother, the
fact would terminate the question of the transmission
of acquired characteis — and this quite as effectually
as would a similarly positive result in the case of
progeny from an ingrafted ovary of a different
variety. In point of fact, the only difference between
the two cases would be, that in the former it might
prove possible to close the question on the side of
Lamarckianism, in the latter it would certainly
close the question, either on this side or on the
opposite as the event would determine.

The only additional fact that has hitherto been
published by the school of Wcismann is the result
of Weismann's own experiment in cutting off the
tails of mice through successive generations. But
this experiment does not bear upon any question
that is in debate ; for no one who is acquainted
with the literature of the subject would have expected

Characters^ Hereditary and Acquired, 149

any positive result to follow from such a line of
inquiry. As shown further back in the text, Darwin
had carefully considered the case of mutilations,
and explained that their non-transmissibility con-
stitutes no valid objection to his theory of pangenesis.
Furthermore, it may now be added, he expressly
alluded in this connexion to the cutting off of tails,
as practised by horse-breeders and dog-fanciers,
"through a number of generations, without any
inherited effect." He also alluded to the still better
evidence which is furnished by the practice of cir-
cumcision. Therefore it is difficult to understand
the object of Weismann's experiment. Yet, other
than the result of this experiment, no new fact
bearing on the question at issue has been even so
much as alleged.

CHAPTER VI.

Characters as Hereditary and Acquired
(coiulusion ^).

In the foregoing chapters I have endeavoured
to be, before all things, impartial ; and if it seems
that I have been arguing chiefly in favour of the
Lamarckian principles, this has been because the
only way of examining the question is to consider
what has to be said on the affirmative side, and
then to see what the negative side can say in
reply. Before we are entitled to discard the Lamarck-
ian factors in tofo, we must be able to destroy
all evidence of their action. This, indeed, is what
the ultra- Darwinians profess to have done. But
is not their profession premature? Is it not evident
that they have not sufficiently considered certain
general facts of nature, or certain particular results
of experiment, which at all events appear inex-
plicable by the theory of natural selection alone ?
In any case the present discussion has been devoted
mainly to indicating such general facts and par-
ticular results. If I have fallen into errors, either

\} See note appended to Preface. C. Ll. M.J

Characters, Hereditary and Acquired. 151

of statement or of reasoning, it is for the ultra-
Darwinians to correct them ; but it may be well to
remark beforehand, that any criticism of a merely
general kind touching the comparative paucity of the
facts thus adduced in favour of Lamarckian doctrine,
will not stand as a valid criticism. For, as we
have seen in the opening part of the discussion,
even if use-inheritance and direct action of the
environment have been of high importance as factors
of organic evolution, it must be in almost all cases
impossible to dissociate their influence from that
of natural selection — at any rate where plants and
animals in a state of nature are concerned. On
the other hand, experiments expressly devised to
test the question have not hitherto been carried
out. Besides, the facts and arguments here adduced
are but comparatively few. For. unless it can be
shown that what has been said of reflex action,
instinct, so-called '* self-adaptation " in plants, &c., is
wrong in principle, the facts which tell in favour
of Lamarckian theory are absolutely very numerous.
Only when considered in relation to cases where
we are unable to exclude the conceivable possi-
bility of natural selection having been at work, can
it be said that the facts in question are not
numerous.

Comparatively few, then, though the facts may
be of which I have given some examples, in my
opinion they are amply sufficient for the purpose
in hand. This purpose is to show that the question
which we are now considering is very far from
being a closed question ; and, therefore, that the
school of Weismann is much too precipitate in

152 Darwin^ and after Darwin.

alleging that there is neither any necessity for,
nor evidence of, the so-called Lamarckian factors^.
And this opinion, whatever it may be worth, is
at all events both deliberate and impartial. As
one of the first to doubt the transmission of acquired
characters, and as one who has spent many years
in experimental inquiries upon the subject, any
bias that I may have is assuredly against the
Lamarckian principles — seeing that nearly all my
experiments have yielded negative results. It was
Darwin himself who checked this bias. But if the
ultra-Darwinians of the last ten years had succeeded
in showing that Darwin was mistaken, I should be
extremely glad to fall into line with them. As
already shown, however, they have in no way affected
this question as it was left by Galton in 1875. And
if it be supposed a matter of but little importance
whether we agree with Galton in largely diminish-
ing the comparative potency of the Lamarckian
principles, or whether we agree with Weismann
in abolishing them together, it cannot be too often
repeated that such is an entirely erroneous view.
No matter how faintly or how fitfully acquired
characters may be transmitted, in so far as they
are likewise adaptive characters, their transmission
(and therefore their development) must be cumu-
lative. Hence, the only effect of attenuating our
estimate of their intensity, is that of increasing
our estimate of their duration — i.e. of the time over
which they have to operate in order to produce

1 E. g. " The supposed transmission of this artificially produced
disease (epilepsy) is the only definite instance which has been brought
forward in support of the transmission of acquired characters." — Essays^
p. 328.

I

Characters, Hereditary and Acquired. 153

important results. And, even so, it is to be re-
membered that the importance of such results is
not to be estimated by the magnitude of modification.
Far more is it to be estimated by the character
of modification as adaptive. For if functionally
produced changes, and changes produced in adaptive
response to the environment, are ever transmitted
in a cumulative manner, a time must sooner or
later arrive when they will reach a selective value
in the struggle for existence — when, of course, they
will be rapidly augmented by natural selection.
Thus, if in any degree operative at all, the great
function of these principles must be that of supplying
to natural selection those incipient stages of adaptive
modifications in all cases where, but for their
agency, there would have been nothing of the kind
to select. Themselves in no way dependent on
adaptive modifications having already attained a
selective value, these Lamarckian principles are
(under the Darwinian theory) direct causes of deter-
minate variation in adaptive lines; and variation
in those lines being cumulative, the result is that
natural selection is in large part presented with the
raw material of its manufacture — special material of
the particular kinds required, as distinguished from
promiscuous material of all kinds. And the more
complex the manufacture the more important will
be the work of this subordinate factory. We can
well imagine how the shell of a nut, for instance,
or even the protective colouring of an insect, may
have been gradually built up by natural selection
alone. But just in proportion as structures or organs
are not merely thus of passive use (where, of course.

154 Darwin^ and after Darwin,

the Lamarckian principles cannot obtain), but require
to be actively used, in that proportion does it become
difficult to understand the incipient construction
of them by natural selection alone. Therefore, in
many such cases, if the incipient construction is
not to be explained by the Lamarckian principles,
it is difficult to see how it is to be explained at all.

Furthermore, since the question as to the trans-
mission of acquired characters stands now exactly
as it did after the publication of Mr. Galton's
Theory of Heredity twenty years ago, it would seem
that our judgement with regard to it should remain
exactly what it was then. Although we must
"out-Darwin Darwin" to the extent of holding
that he assigned too large a measure of intensity
to the Lamarckian factors, no sufficient reason
has been shown for denying the existence of
these factors in toto\ while, on the other hand
there are certain general considerations, and certain
particular facts, which appear to render it prob-
able that they have played a highly important
part in the process of organic evolution as a whole.
At the same time, and in the present state of
our information, this judgement must be deemed
provisional, or liable eventually to be overturned
by experimental proof of the non-inheritance of
acquired characters. But, even if this should ever
be finally accomplished, the question would still
remain whether the principle of natural selection
alone is capable of explaining all the facts of adap-
tation ; and, for my own part, I should then be
disposed to believe that there must be some other.
though hitherto undiscovered, principle at work,

i

Characters f Hereditary and Acquired, 155

which co-operates with natural selection, by playing
the subordinate role which was assigned by Darwin
to the principles of Lamarck.

Finally, let it be noted that no part of the fore-
going argument is to be regarded as directed against
th^ principle of what Professor Weismann calls ''con-
tinuity." On the contrary, it appears to be self-evident
that this principle must be accepted in some degree
or another by every one, whether Darwinians, Neo-
Darwinians, Lamarckians, Neo-Lamarckians, or even
the advocates of special creation. Yet, to hear or
to read some of the followers of Weismann, one
can only conclude that, prior to his publications on
the subject, they had never thought about it at all.
These naturalists appear to suppose that until then
the belief of Darwinians was, that there could be
no hereditary " continuity " between any one organic
type and another (such, for instance, as between
Ape and Man), but that the whole structure of any
given generation must be due to "gemmules"
or " somato-plasm," derived exclusively from the
preceding generation. Nothing can show more
ignorance, or more thoughtlessness, with regard to
the whole subject. The very basis of the general
theory of evolution is that there must always have
been a continuity in the material substance of
heredity since the time when the process of evolution
began ; and it was not reserved for our generation,
or even for our century, to perceive the special
nature of this material substance in the case of sexual
organisms. No, the real and the sole question, where
Weismann's theory of heredity is concerned, is simply
this — Are we to hold that this material substance

156 Darwifiy and after Darwin,

has been absolutely continuous " since the first origin
of sexual propagation," always occupying a separate
"sphere" of its own, at all events to the extent of
never having been modified by the body substance
in which it resides (Lamarckian factors); or, are
we to hold that this " germ-plasm," " stirp,*' or " forma-
tive-material," has been but relatively continuous,
so as to admit of some amount of commerce
with body-substance, and therefore to admit of
acquired characters, when sufficiently long continued
as such, eventually becoming congenital? If this
question be answered in the latter sense, of course
the further question arises as to the degree of
such commerce, or the time during which acquired
characters must continue to be acquired in suc-
cessive generations before they can sufficiently
impress themselves on the substance of heredity
to become congenital. But this is a subordinate
question, and one which, in the present state of
our information, it seems to me almost useless to
speculate upon. My own opinion has always been
the same as that of Mr. Galton ; and my belief is
that eventually both Weismann and his followers
will gravitate into it. It was in order to precipitate
this result as far as possible that I wrote the
Examination, If it ever should be accomplished,
Professor Weismann's elaborate theory of evolution
will have had its bases removed.

SECTION II

UTILITY

CHAPTER VII.

Characters as Adaptive and Specific.

One of the great changes which has been wrought
in biological science by the Darwinian theory of
natural selection, consists in its having furnished
an intelligible explanation of the phenomena of
adaptaiio7i. Indeed, in my opinion, this is the most
important function which this theory has had to
perform ; and although we still find systematic
zoologists and systematic botanists who hold that
the chief merit of Darwin's work consists in its
having furnished an explanation of the origin of
species^ a very little consideration is enough to
show that such an idea is but a survival, or a
vestige, of an archaic system of thought. So long
as species were regarded as due to separate acts
of creation, any theory which could explain their
production by a process of natural evolution became
of such commanding importance in this respect,
that we cannot wonder if in those days the principal
function of Darwin's work was' held to be what
the title of that work — The Origin of Species by
means of Natural Selection — itself serves to convey.
And, indeed, in those days this actually was the
principal function of Darwin's work, seeing that in

i6o Darwin^ and after Darwin,

those days the fact of evolution itself, as distin-
guished from its method, had to be proved ; and
that the whole proof had to stand or fall with
the evidence which could be adduced touching the
mutability of species. Therefore, without question,
Darwin was right in placing this issue as to the
stability or instability of species in the forefront of
his generalizations, and hence in constituting it the
title of his epoch-making book. But nowadays, when
the fact of evolution has been sufficiently established,
one would suppose it self-evident that the theory
of natural selection should be recognized as cover-
ing a very much larger field than that of explaining
the origin of species — that it should be recognized
as embracing the whole area of organic nature in
respect of adaptations, whether these happen to be
distinctive of species only, or of genera, families,
orders, classes, and sub-kingdoms. For it follows
from the general fact of evolution that species are
merely arbitrary divisions, which present no deeper
significance from a philosophical point of view than
is presented by well-marked varieties, out of which
they are in all cases believed to have arisen, and
from which it is often a matter of mere individual
taste whether they shall be separated by receiving
the baptism of a specific name. Yet, although
naturalists are now unanimously agreed that what
they classify as species are nothing jnore than
pronounced — and in some greater or less degree
permanent — varieties, so forcible is the influence of
traditional modes of thought, that many zoologists
and botanists still continue to regard the origin of
species as a matter of more importance than the origin

Characters as Adaptive and Specific, i6i

of adaptations. Consequently, they continue to repre-
sent the theory of natural selection as concerned,
primarily, with explaining the origin of species,
and denounce as a "heretic" any one who regards
the theory as primarily a theory of the origin and
cumulative development of adaptations — whether
structural or instinctive, and whether the adaptations
are severally characteristic of species only or of
any of the higher taxonomic divisions. Indeed, these
naturalists appear to deem it in some way a dis-
paragement of the theory to state that it is, primarily,
a theory of adaptations, and only becomes second-
arily a theory of species in those comparatively
insignificant cases where the adaptations happen
to be distinctive of the lowest order of taxonomic
division — a view of the matter which may fitly
be compared to that of an astronomer who should
define the nebular hypothesis as a theory of the
origin of Saturn's rings It is indeed a theory of the
orig n of Saturn's rings ; but only because it is a theory
of the origin of the entire solar system, of which
Saturn's rings form a part. Similarly, the theory
of natural selection is a theory of the entire system
of organic nature in respect of adaptations, whether
these happen to be distinctive of particular species
only, or are common to any number of species.

Now the outcry which has been raised over this
definition of the theory of natural selection is
a curious proof of the opposition which may be
furnished by habitual modes of thought to an exceed-
ingly plain matter of definition. For, I submit, that
no one can deny any of the following propositions ;
nor can it be denied that from these propositions

TT M

i62 Darwin, and after Darwin.

the foregoing definition of the theory in question
follows by way of necessity. The propositions are,
first, that natural selection is taken to be the
agency which is mainly, if not exclusively, con-
cerned in the evolution of adaptive characters:
secondly, that these characters, when evolved, are in
some cases peculiar to single species only, while in
other cases, and in process of time, they become
the common property of many species : thirdly, that
in cases where they are peculiar to single species
only, they constitute at all events one of the reasons
(or even, as the ultra-Darwinians believe, the only
reason) why the particular species presenting them
have come to be species at all. Now, these being
the propositions on which we are all agreed, it
obviously follows, of logical necessity, that the theory
in question is primarily one which explains the exis-
tence of adaptive characters wherever these occur ;
and, therefore, whether they happen to be restricted
to single species, or are common to a whole
group of species. Of course in cases where they
are restricted to single species, the theory which
explains the origin of these particular adaptations
becomes also a theory which explains the origin
of these particular species ; seeing that, as we are
all agreed, it is in virtue of such particular adapta-
tions that such particular species exist. Yet even
in these cases the theory is, primarily, a theory
of the adaptations in virtue of which the particular
species exists ; for, ex hypothesis it is the adaptations
which condition the species, not the species the
adaptations. But, as just observed, adaptations may
be the con^"i.on property of whole groups of species :

I

Characters as Adaptive and Specific. 163

and thus the theory of natural selection becomes
a theory of the origin of genera, of families, of orders,
and of classes, quite as much as it is a theory of the
origin of species. In other words, it is everywhere
a theory of adaptations ; and it is only where
the adaptations happen to be restricted to single
species that the theory therefore and incidentally
becomes also a theory of the particular species which
presents them. Hence it is by no means the same
proposition to affirm that the theory of natural
selection is a theory of the origin of species, and
that it is a theory of the origin of adaptations, as
some of my critics have represented it to be ; for
these two things are by no means conterminous.
And in as far as the two propositions differ, it is
perfectly obvious that the latter is the true one.

Possibly, however, it may be said — Assuredly natural
selection is a theory of the origin (i. e. cumulative
development) of adaptations ; and, no less assuredly,
although species owe their origin to such adaptations,
there is now no common measure between these two
things, seeing that in numberless cases the same
adaptations are the common property of numberless
species. But. allowing all this, we must still remember
that in ihoAX first beginnings all these adaptations must
have been distinctive of, or peculiar to, some one par-
ticular species, which afterwards gave rise to a whole
genus, family, order, or class of species, all of which
inherited the particular adaptations derived from
this common ancestor, while progressively gaining
additional adaptive characters severally distinctive of
their subsequently diverging lines of descent. So
that really all adaptive characters must originally

M 2

164 Darwifij and after Darwin.

have been specific characters ; and therefore there is
no real distinction to draw between natural selection
as a theory of species and as a theory of adaptations.
Well, if this objection were to be advanced, the
answer would be obvious. Although it is true that
every adaptive character which is now common to
a group of species must originally have been dis-
tinctive of a single parent species, it by no means
follows that in its first beginning as a specific character
it appeared in the fully developed form which it now
presents as a generic, family, ordinal, or yet higher
character. On the contrary, it is perfectly certain
that in the great majority of instances such cannot
possibly have been the case ; and the larger the group
of species over which any particular adaptive character
now extends, the more evidently do we perceive that
this character must itself have been the product of
a gradual evolution by natural selection through an
innumerable succession of species in branching lines.
The wing of a bird, for example, is an adaptive
structure which cannot possibly have ever appeared
suddenly as a merely specific character : it must have
been slowly elaborated through an incalculable number
of successive species, as these branched into genera,
families, and orders of the existing class. So it is
with other class distinctions of an adaptive kind;
and so, in progressively lessening degrees, is it with
adaptive characters of an ordinal, a family, or a generic
value. That is to say, in all cases where an adaptive
structure is common to any considerable group of
species, we meet with clear evidence that the structure
has been the product of evolution through the ancestry
of those species ; and this evidence becomes in-

Characters as Adaptive and Specific, T65

creasingly cogent the higher the taxonomic value
of the structure. Indeed, it may be laid down as
a general rule, that the greater the degree of adapta-
tion the greater is its diffusion — both as regards
the number of species which present it now, and
the number of extinct species through which it has
been handed down, in an ever ramifying extension
and in an ever improving form. Species, therefore,
may be likened to leaves : successive and transient
crops are necessary for the gradual building up of
adaptations, which, like the woody and permanent
branches, grow continuously in importance and
efficiency through all the tree of life. Now, in my
view, it is the great office of natural selection to see
to the growth of these permanent branches ; and
although natural selection has likewise had an enor-
mously large share in the origination of each suc-
cessive crop of leaves — nay, let it be granted to the
ultra- Darwinians for the sake of argument, an ex-
clusive prerogative in this respect— still, in my view,
this is really the least important part of its work.
Not as an explanation of those merely permanent
varieties which we call species, but as an explanation
of the adaptive machinery of organic nature, which
has led to the construction both of the animal and
vegetable kingdoms in all their divisions do I regard
the Darwinian theory as one of the greatest general-
izations in the history of science.

I have dwelt thus at some length upon a mere
matter of definition because, as we shall now find,
although it is but a matter of definition, it is fraught
with consequences of no small importance to the

i66 Darwin^ and after Darwin,

general theory of descent. Starting from an erroneous
definition of the theor}^ of natural selection as primarily
a theory of the origin of species, both friends and
foes olf the theory have concluded that the principle
of utility must by hypothesis be of universal occur-
rence so far as species are concerned ; whereas, if once
these naturalists were to perceive that their definition
of the theory is erroneous, they would likewise
perceive that their conclusion cannot follow deduc-
tively from the theory itself. If such a conclusion is
to be established at all, it can only be by other
and independent evidence of the inductive kind — to
wit, by actual observation.

Hence we see the importance of starting with an
accurate definition of the theory before proceeding
to examine the doctrine of utility as of universal
application to species — a doctrine which, as just
stated, has been habitually and expressly deduced
from the theory. This doctrine occurs in two forms ;
or, more correctly, there are with reference to this
subject two distinct doctrines, which partly coincide
and partly exclude one another. First, it is held by
some naturalists that all species must necessarily owe
their origin to natural selection. And secondly, it is
held by other naturalists, that not only all species,
but likewise all specific characters must necessarily
do the same. Let us consider these two doctrines
separately.

The first, and less extensive doctrine, rests on the
deduction that every species must owe its differentiation
as a species to the evolution of at least one adaptive
character, which is peculiar to that species. Although,
when thus originated, a species may come to present

Characters as Adaptive and Specific. 167

any number of other peculiar characters of a non-
adaptive kind, these merely indifferent peculiarities
are supposed to hang, as it were, on the peg supplied
by the one adaptive peculiarity ; it is the latter which
conditions the species, and so furnishes an oppor-
tunity for any number of the former to supervene.
But without the evolution of at least one adaptive
character there could have been no distinct species,
and therefore no merely adventitious characters as
belonging to that species. I will call this the
Huxleyan doctrine, because Professor Huxley is its
most express and most authoritative supporter.

The second and more extensive doctrine I will call,
for the same reason, the Wallacean doctrine. This
is, as already stated, that it follows deductively from
the theory of natural selection, that not only all
species, but even all the distinctive characters of every
species, must necessarily be due to natural selection ;
and, therefore, can never be other than themselves
useful, or, at the least, correlated with some other
distinctive characters which are so.

Here, however, I should like to remark paren-
thetically, that in choosing Professor Huxley and
Mr. Wallace as severally representative of the doctrines
in question, I earnestly desire to avoid any appearance
of discourtesy towards such high authorities.

I am persuaded — as I shall hereafter seek to show
Darwin was persuaded— that the doctrine of utility as
universal where species are concerned, is, in both the
above forms, unsound. But it is less detrimental
in its Huxleyan than in its Wallacean form, be-
cause it does not carry the erroneous deduction to
so extreme a point. Therefore let us first consider

m68 Darwifif and after Darwtn.

the doctrine in its more restricted form, and then pro-
ceed, at considerably greater length, to deal with it in
its more extended form.

The doctrine that all species must necessarily be due
to natural selection, and therefore must severally
present at least one adaptive character, appears to me
doubly erroneous.

In the first place, it is drawn from what I have
just shown to be a false premiss ; and, in the second
place, the conclusion does not follow even from this
premiss. That the premiss — or definition of the theory
as primarily a theory of the origin of species — is false,
I need not wait again to argue. That the conclusion
does not follow even from this erroneous premiss,
a very few words will suffice to prove. For, even if
it were true that natural selection is primarily a theory
of the origin of species, it would not follow that it
must therefore be a theory of the origin of all species.
This would only follow if it were first shown that the
theory is not merely a theory of the origin of species,
but the theory of the origin of species — i.e. that there
can be no further theory upon this subject, or any
cause other than natural selection which is capable of
transforming any single specific type.

Needless to say, this cannot be shown by way of
deduction from the theory of natural selection itself —
which, nevertheless, is the only way whereby it is
alleged that the doctrine is arrived at^

From the doctrine of utility as advocated by Professor

» For a full treatment of Professor Huxley's views upon this subject^
see Appendix II.

Characters as Adaptive and Specific. 169

Huxley, we may now pass on to consider it in
the much more comprehensive form advocated by
Mr. Wallace. Of course it is obvious that if the
doctrine is erroneous in its Huxleyan form, much
more must it be so in its Wallacean ; and, therefore
that having shown its erroneousness in its less extended
application, there is little need to consider it further in
its more extended form. Looking, however, to its
importance in this more extended application, I think
we ought to examine it independently as thus pre-
sented by Mr. Wallace and his school. Let us therefore
consider, on its own merits, the following statement : —
It follows directly from the theory of natural
selection that not only all species, but likewise all
specific characters, must be due to natural selection,
and, therefore, must all be of use to the species
which present them, or else correlated with other
characters which are so.

It seems worth while to observe, in limine, that
this doctrine is contradicted by that of Professor
Huxley. For supposing natural selection to be the
only principle concerned in the origin of all species,
it by no means follows that it is the sole agency
concerned in the origin of all specific characters.
It is enough for the former proposition if only
some of the characters distinctive of any given
|| species — nay, as he very properly expresses it, if
only one such character — has been due to natural
selection ; for it is clear that, as he adds. " any number
of indifferent [specific] characters ' may thus have
been furnished with an opportunity, so to speak, of
being produced by causes other than natural selection.
Hence, as previously remarked, the Huxleyan doctrine,

T70 Darwin, and after Darwin,

although coinciding with the Wallacean up to the
point of maintaining utility as the only principle
which can be concerned in the origin of species,
designedly excludes the Wallacean doctrine where
this proceeds to extend any similar deduction to the
case of specific characters ^.

In the next place, and with special reference to the
Wallacean doctrine, it is of importance to observe
that, up to a certain point there is complete agreement
between Darwinists of all schools. We all accept
natural selection as a true cause of the origin of species
(though we may not all subscribe to the Huxleyan
deduction that it is necessarily a cause of the origin of
all species). Moreover, we agree that specific characters
are often what is called rudimentary or vestigial ; and,
once more, that our inability to detect the use of
any given structure or instinct is no proof that such
a structure or instinct is actually useless, seeing that
it may very probably possess some function hitherto
undetected, or possibly undetectable. Lastly, we all
agree that a structure which is of use may incidentally
entail the existence of some other structure which is
not of use ; for, in virtue of the so-called principle of
correlation, the useless structure may be an indirect
consequence of natural selection, since its development
may be due to that of the useful structure with the
growth of which the useless one is correlated.

Nevertheless, while fully conceding all these facts
and principles to the Wallacean party, those who
think with Professor Huxley — and still more, of course,
those few naturalists who think as I do — are unable

* Professor Huxley's views upon this matter are quoted in extenso in
Appendix II.

Characters as Adaptive and Specific. 171

to perceive that they constitute any grounds for
holding the doctrine that all specific characters are,
or formerly have been, directly or indirectly due to
natural selection. My own reasons for dissenting
from this Wallacean doctrine are as follows.

From what has just been said, it will be apparent
that the question in debate is not merely a question
of fact which can be settled by a direct appeal to
observation. If this were the case, systematic natur-
alists could soon settle the question by their detailed
knowledge of the structures which are severally
distinctive of any given group of species. But so far
is this from being the case, that systematic naturalists
are really no better qualified to adjudicate upon the
matter than are naturalists who have not devoted so
much of their time to purely diagnostic work. The
question is one of general principles, and as such
cannot be settled by appeals to special cases. For
example, suppose that the rest of this chapter
were devoted to a mere enumeration of cases where
it appears impossible to suggest the utility of certain
specific characters, although such cases could be
adduced by the thousand, how should I be met at the
end of it all ? Not by any one attempting to suggest
the utility, past or present, of the characters named ;
but by being told that they must all present some
hidden use, must be vestigial, or else must be due to
correlation. By appealing to one or other of these as-
sumptions, our opponents are always able to escape the
necessity of justifying their doctrine in the presence of
otherwise inexplicable facts. No matter how many
seemingly " indifferent characters '' we may thus accumu-

172 DarwiHy and after Darwin,

late, Mr. Wallace and his followers will always throw
upon us the impossible burden of proving the negative,
that these apparently useless characters do not present
some hidden or former use, are not due to correlation,
and therefore have not been produced by natural selec-
tion. It is in vain to retort that the burden of proof
really lies the other way, or on the side of those who
affirm that there is utility where no man can see
it, or that there is correlation where no one can
detect it. Thus, so far as any appeal to particular
facts is concerned, it does not appear that there is any
modus vivendi. Our opinions upon the question are
really determined by the views which we severally
take on matters of general principle. The issue,
though it has a biological bearing, is a logical issue,
not a biological one: it turns exclusively on those
questions of definition and deduction with which
we have just been dealing.

But although it thus follows that we cannot
determine in fact what proportion of apparently
useless characters are or are not really useful, we
may very easily determine in fact what proportion
of specific characters fail to present any observable
evidences of utility. Yet, even upon this question of
observable fact, it is surprising to note the diver-
gent statements which have of late years been
made by competent writers ; statements in fact so
divergent that they can only be explained by some
want of sufficient thought on the part of those
naturalists who are antecedently persuaded tliat all
specific characters must be either directly or in-
directly due to natural selection. Hence they fail
to give to apparently useless specific characters the

Characters as Adaptive and Specific, 173

attention which, apart from any such antecedent
persuasion, they deserve. For example, a few years
ago I incidentally stated in a paper before the
Linnaean Society, that " a large proportional number
of specific characters " are of a trivial and apparently
unmeaning kind, to which no function admits of being
assigned, and also stated that Darwin himself had
expressly given utterance to the same opinion.
When these statements were made, I did not antici-
pate that they would be challenged by anybody,
except perhaps, by Mr. Wallace. And, in order now
to show that my innocence at that time was not
due to ignorance of contemporary thought on such
matters, a sentence may here be quoted from a
paper which was read at the meeting of the
British Association of the same year, by a highly
competent systematic naturalist, Mr. Henry Seebohm,
and soon afterwards extensively republished. Criti-
cizing adversely my then recently published paper,
he said : —

" I fully admit the truth of this statement ; and I presume
that few naturalists would be prepared to deny that ' distinctions
of specific value frequently have reference to structures which
are without any utilitarian significance \' "

But since that time the course of Darwinian specu-
lation has been greatly influenced by the writings of
Weismann, who, among other respects in which he
out-darwins Darwin, maintains the doctrine of utility
as universal. In consequence of the influence which
these writings have exercised, I have been more
recently and extensively accused of ' heresy " to
Darwinian principles, for having stated that " a large

' Geographical Distribution of the Family Charadriidae, p. 19.

174 Darwifiy and after Darwin.

proportional number of specific characters " do not
admit of being proved useful, or correlated with other
characters that are useful. Now, observe, we have
here a simple question of fact. We are not at present
concerned with the question how far the argument
from ignorance may be held to apply in mitigation
of such cases ; but we are concerned only with the
question of fact, as to what proportional number of
cases actually occur where we are unable to suggest
the use of specific characters, or the useful characters
with which these apparently useless ones are corre-
lated. I maintain, as a matter of fact, that the cases
in question embrace *' a large proportional number
of specific characters." On the other hand, I am
accused of betraying ignorance of species, and of the
work of *' species-makers," in advancing this state-
ment ; and have been told by Mr. Wallace, and
others of his school, that there is absolutely no
evidence to be derived from nature in support of my
views. Well, in the first place, if this be the case,
it is somewhat remarkable that a large body of
competent naturalists, such as Bronn, Broca, Nageli,
Kerner, Sachs, De Vries, Focke, Henslow, Haeckel,
Kolliker. Eimer. Giard. Pascoe, Mivart, Seebohm,
Lloyd Morgan, Dixon, Beddard, Geddes Gulick, and
also, as we shall presently see, Darwin himself, should
have fallen into the same error. And it is further
remarkable that the more a man devotes himself to
systematic work in any particular department —
whether as an ornithologist, a conchologist, an ento-
mologist, and so forth —the less is he disposed to
accept the dogma of specific characters as universally
adaptive characters. But, in the second place, and

I

Characters as Adaptive and Specific. 175

quitting considerations of mere authority, I appeal
to the facts of nature themselves ; and will now
proceed, as briefly as possible, to indicate the result
of such an appeal.

For the following reasons, that birds and mam-
mals seem to furnish the best field for testing the
question by direct observation. First, these classes
present many genera which have been more care-
fully worked out than is usually the case with
genera of invertebrates, or even of cold-blooded
vertebrates. Secondly, they comprise many genera
each including a large number of species, whose
habits and conditions of life are better known than
is the case with species belonging to large genera
of other classes. Thirdly, as birds and mammals
represent the highest products of evolution in respect
of organization, a more severe test is imposed than
could be imposed elsewhere, when the question is
as to the utility of specific characters; for if these
highest products of organization fail to reveal, in a
large proportional number of cases, the utility of their
specific characters, much more is this likely to be the
Case among organic beings which stand lower in the
scale of organization, and therefore, ex hypothesis
are less elaborate products of natural selection.
Fourthly, and lastly, birds and mammals are the
classes which Mr. Wallace has expressly chosen to
constitute his ground of argument with regard to
the issue on which we are now engaged.

It would take far too long to show, even in epi-
tome, the results of this inquiry. Therefore I will
only state the general upshot. Choosing genera of
birds and mammals which contain a large number

176 Darwin^ and after Darwin,

of species whose diagnostic characters have been
worked out with most completeness, I restricted
the inquiry to specific distinctions of colour, not
only for the sake of having a uniform basis for
comparisons, but still more because it seemed that
the argument from our ignorance of possibly un-
known uses could be more successfully met in the
case of slight differences of colour or of shading,
than in that of any differences of structure or of
form. Finally, after tabulating all the differences of
colour which are given as diagnostic of each species
in a genus, and placing in one column those which
may conceivably be useful, while placing in another
column those of which it appeared inconceivable
that any use could be suggested, I added up the
figures in the two columns, and thus obtained a
grand total of all the specific characters of the
genus in respect of colours, separated into the two
classes of conceivably useful and apparently useless.
Now, in all cases the apparently useless characters
largely preponderated over the conceivably useful
ones ; and therefore I abundantly satisfied myself
regarding the accuracy of my previous statement,
that a large proportional number— if not an actual
majority — of specific characters belong to the latter
category.

The following is a brief abstract of these results.

With respect to Birds, a large number of cases
were collected wherein the characters of allied
species differ from one another in such minute
respects of colour or shading, that it seemed unrea-
sonable to suppose them due to any selective
value to the birds in question. It is needless —

Characters as Adaptive and Specific. 177

even if it were practicable on the present occa-
sion— to adduce this evidence in detail, since an
exceedingly good sample of it may be found in
a small book which is specially devoted to consider-
ing the question in its relation to birds. I allude
to an essay by Mr. Charles Dixon, entitled Evolu-
tion without Natural Selection (1885). In this work
Mr. Dixon embodies the results of five years' " care-
ful working at the geographical distribution and
variations of plumage of Palaearctic birds and their
allies in various other parts of the world" ; and
shows, by a large accumulation of facts, not only
that there is no utility to be suggested in reference
to the minute or trivial differences of colouration
which he describes ; but also that these differences
are usually correlated with isolation on the one
hand, or with slight differences of climate on the
other. Now it will be shown later on that both
these agents can be proved, by independent evidence,
capable of inducing changes of specific type with-
out reference to utility : therefore the correlation
which Mr. Dixon unquestionably establishes between
apparently useless (because utterly trivial) specific
distinctions on the one hand, and isolation or
climatic change on the other, constitutes additional
evidence to show that the uselessness is not only
apparent, but real. Moreover I have collected a
number of cases where such minute differences of
colour between allied species of birds happen to
affect parts of the plumage which are concealed — as
for instance, the breast and abdomen of creepers. In
such cases it seems impossible to suggest how natural
selection can have operated, seeing that the parts
IL N

178 Darwin^ and after Darwin,

affected are not exposed to the view either of enemies
or of prey.

Analogous illustrations to any amount may be drawn
from Mammals. For instance, I have worked through
the Marsupials with the aid of Mr. Oldfield Thomas'
diagnostic description of their numerous species.
Now, let us take any one of the genera, such as
the kangaroos. This comprises 23 species living on
an island continent of high antiquity, and not ex-
posed to the depredations of any existing carnivor-
ous enemies ; so that there is here no present need
to vary colour for purposes of protection. More-
over, in all cases the diagnostic distinctions of
colour are so exceedingly trivial, that even if large
carnivora were recently abundant in Australia, no one
could reasonably suggest that the differences in
question would then have been protective. On an
average, each of the 23 species presents rather more
than 20 peculiarities of shading, which are quoted
as specifically diagnostic. Altogether there are 474
of these peculiarities distributed pretty evenly among
the 23 species ; and m no case can I conceive that
utility can be suggested.

Hitherto we have been considering the question of
fact, as to whether " a large proportional number
of specific characters " do or do not admit of having
their utility demonstrated, or even so much as plaus-
ibly suggested. In the result, I can only conclude
that this question of fact is really not an open one,
seeing that it admits of an abundantly conclusive
answer by any naturalist who will take the trouble
to work through the species of any considerable

Characters as Adaptive and Specific. 179

number of genera in the way above indicated. But
although the question of fact is thus really closed,
there remains a more ultimate question as to its
theoretical interpretation. For, as already pointed
out, no matter how great an accumulation of such
facts may be collected, our opponents are always able
to brush them aside by their a priori appeal to the
argument from ignorance. In effect they say — We
do not care for any number of thousands of such
facts ; it makes no difference to us what ' proportional
number" of specific characters fail to show evidence
of utility ; you are merely beating the air by adducing
them, for we are already persuaded, on antecedent
grounds, that all specific characters must be either
themselves useful, or correlated with others that are,
whether or not we can perceive the utility, or suggest
the correlation.

To this question of theoretical interpretation, there-
fore, we must next address ourselves. And here,
first of all, I should like to point out how sturdy must
be the antecedent conviction of our opponents, if
they are to maintain it in the face of such facts as
have just been adduced. It must be remembered
that this antecedent conviction is of a most uncom-
promising kind. By its own premisses it is committed
to the doctrine that all specific characters, without
a single exception, must be either useful, vestigial, or
correlated. Well, if such be the case, is it not some-
what astonishing tliat out of 474 differences of colour
which are distinctive of the 23 species of the genus
Macropus, no single one appears capable of having any
utility demonstrated, or indeed so much as suggested ?
For even the recent theory that slight differences of

N 2

i8o DarwiUy and after Darwin,

colour, which cannot be conceived as serving any
other purpose, may enable the sexes of the same
species quickly to recognize each other, is not here
available. The species of the genus Macropus are
more conspicuously distinguished by differences of size
and form than by these minute differences^of colour;
and therefore no such use can be attributed to the
latter. And, as previously stated, even within the
order Marsupialia the genus Macropus is not at all
exceptional in this respect ; so that by including
other genera of the order it would be easy to gather
such apparently indifferent specific characters by
the hundred, without any one of them presenting
evidence — or even suggestion — of utility. How robust
therefore is the faith of an a priori conviction which
can stand against such facts as these! What, then,
are the a priori grounds on which it stands?
Mr. Wallace, the great leader of this school of thought,
says : —

" It is a necessary deduction from the theory of natural selec-
tion, that none of the definite facts of organic nature, no special
organ, no characteristic form or marking, no peculiarities of
instinct or of habit, no relations between species or between
groups of species, can exist, but which must now be, or once
have been, useful to the individuals or the races which possess
them V

Here, then, we have in brief compass the whole
essence of our opponents' argument. It is confessedly
an argument a priori, a deduction from the theory
of natural selection, a supposed consequence of that
theory which is alleged to be so necessary that to

' Contributions to the Theory of Natural Selection^ p. 47 (1870) ; re-
published in 1892.

Characters as Adaptive and Specific, i8i

dispute the consequence is tantamount to denying the
theory from which it is derived. In short, as before
stated, it is a question of theory, not a question of
fact : our difference of opinion is logical, not biological :
it depends on our interpretation of principles, not
on our observation of species. It will therefore be
my endeavour to show that the reasoning in question
is fallacious : that it is not a necessary deduction
from the theory of natural selection that no character-
istic form or marking, no peculiarities of instinct or
of habit, can exist, but which must now be, or once
have been, useful, or correlated with some other
peculiarity that is useful.

'• The tuft of hair on the breast of a wild turkey-
cock cannot be of any use, and it is doubtful whether
it can be ornamental in the eyes of the female bird ;
— indeed, had the tuft appeared under domestication,
it would have been called a monstrosity ^.'*

As a matter of common sense, unprejudiced by
dogma, this appears to be a perfectly sound judgement;
but if Wallace had asked Darwin to prove such
a negative, Darwin could only have replied that it
was for Wallace to prove the affirmative— and thus
the issue would have been thrown back upon a dis-
cussion of general principles. Then Wallace would
have said — " The assertion of inutility in the case of
-my organ or peculiarity which is not a rudiment or
a correlation is not, and can 7iever be, the statement
of a fact, but merely an expression of our ignorance of
its purpose or origin ^." Darwin, however, would have
replied : — " Our ignorance of the laws of variation is

^ Origin of Species, p. 70 : italics mine.
' Danvinism, p. 137 : italics mine.

i82 DarwiUf and after Daf^n.

profound " ; and while, on this account, we ought " to
be extremely cautious in pretending to decide what
structures are now, or Jiave formerly been^ of use to
each species!^ in point of fact. *' there can be little
doubt that the tendency to vary in the same manner
has often been so strong, that all individuals of the
same species have been similarly modified without the
aid of any form of selection ^.'*

It will be my endeavour in the following discussion
to show that Darwin would have had an immeasurable
advantage in this imaginary debate.

To begin with, Wallace's deductive argument is
a clear case of circular reasoning. We set out by infer-
ring that natural selection is a cause from numberless
cases of observed utility as an effect : yet, when " in
a large proportional number*' of cases we fail to
perceive any imaginable utility, it is argued that
nevertheless utility must be there, since otherwise
natural selection could not have been the cause.

Be it observed, in any given case we may properly
anticipate utility as probable, even where it is not
perceived ; because there are already so enormous
a number of cases where it is perceived, that, if the
principle of natural selection be accepted at all, we must
conclude with Darwin that it is " the main means of
modification." Therefore, in particular cases of un-
perceived utility we may take this antecedent prob-
ability as a guide in our biological researches — as has

* Origin of Species^ p. 73 : Mr. Wallace himself quotes this passage
{Darwinism, p. 141); but says with regard to it "the important word
* all ' is probably an oversight" In the Appendix (^11), on Darwin's
views touching the doctrine of utility I adduce a number of precisely
equivalent passages, derived from all his different works on evolution,
and every one of them presenting " the important word * all.' "

Characters as Adaptive and Specific, 183

been done with such brilliant success both by Darwin
and Wallace, as well as by many of their followers.
But this is a very different thing from laying down '
the universal maxim, that in all cases utility must
be present, whether or not we shall ever be able to
detect it ^. For this universal maxim amounts to an
assumption that natural selection has been the " exclu-
sive means of modification." That it has been " the
main means of modification " is proved by the gener-
ality of the observed facts of adaptation. That it has
been " the exclusive means of modification," with the
result that these facts are universal, cannot be thus
proved by observation. Why, then, is it alleged ?
Confessedly it is alleged by way of deduction from
the theory of natural selection itself. Or, as above
stated, after having deduced the theory from the facts,
it is sought to deduce the facts from the theory.

Thus far I have been endeavouring to show
that the universality of adaptation cannot be inferred
from its generality, or from the theory of natural selec-
tion itself But, of course, the case would be quite
different if there were any independent evidence — or
rather, let us say, any logical argument — to show that
natural selection is " the exclusive means of modifi-
cation.'' For in this event it would no longer involve
circular reasoning to maintain that all specific char-
acters are likewise adaptive characters. It might
indeed appear antecedently improbable that no
other principle than natural selection can possibly
have been concerned in the differentiation of those
relatively permanent varieties which we call species —
that in all the realm of organic nature, and in all the

* See Introductory Chapter, p. ao.

184 Darwin, and after Darwin,

complexities of living processes, there is no room for
any other influence in the production of change, even
of the most trivial and apparently unmeaning kind.
But if there were any good evidence or logical argu-
ment to the contrary, this antecedent presumption
would have to give way ; and the certainty that all
specific characters are likewise adaptive characters
would be determined by the cogency of such evidence
or argument as could be adduced. In short, we are
not entitled to conclude — and still less does it follow
" as a necessary deduction from the theory of natural
selection " — that all the details of specific differentia-
tion must in every case be either useful, vestigial, or
correlated, unless it has been previously shown, by
independent evidence, or accurate reasoning, that there
is no room for any other principle of specific change.

This, apparently, is the central core of the question.
Therefore I will now proceed to consider such argu-
ments as have been adduced to prove that, other
than natural selection, there can have been no " means
of modification." And, after having exhibited the
worthlessness of these arguments, I will devote the
next chapter to showing that, as a matter of ob-
servable fact, there are a considerable number of
other principles, which can be proved to be capable
of producing such minute differences of form and
colour as 'Mn a large proportional number" of cases
constitute diagnostic distinctions between species and
species.

First, then, for the reasons a priori— ^.nd they
are confessedly a priori — which have been adduced
to prove that natural selection has been what in
Darwin's opinion it has not been, — "the exclusive

Characters as Adaptive and Specific, 185

means of modification." Disregarding the Lamarckian
factors — which, even if valid, have but little relation to
the present question, seeing that they are concerned,
almost exclusively, with the evolution of adaptive
characters — it is alleged that natural selection must
occupy the whole field, because no other principle
of change can be allowed to operate in the presence
of natural selection Now, I fully agree that 'this
statement may hold as regards any principle of change
which is deleterious ; but clearly it djoes not hold
as regards any principle which is merely neutral.
If any one were to allege that specific characters
are frequently detrimental to the species presenting
them, he would no doubt lay himself open to the
retort that natural selection could not allow such
characters to persist ; or, which amounts to the same
thing, that it does " necessarily follow from the theory
of natural selection" that specific characters can
never be in any large number, or in any large
measure, harmful to the species presenting them.
But where the statement is that specific characters
are frequently indifferent — again to use Professor
Huxley's term — the retort loses all its relevancy. No
reason has ever been shown why natural selection should
interfere with merely indifferent characters, supposing
such to have been produced by any of the agencies
which we shall presently have to consider. Therefore
this argument — or rather assertion — goes for nothing.
The only other argument I have met with on this
side of the question is one that has recently been
adduced by Mr. Wallace. He says : —

" One very weighty objection to the theory that specific
characters can ever be wholly useless appears to have been

i86 Darwin, and after Darwin.

overlooked by those who have maintained the frequency of
such characters, and that is, their almost necessary instability '."

This argument he proceeds to elaborate at con-
siderable length, but fails to perceive what appears
to me the obvious answer. Provided that the cause
of the useless character is constant, there is no
difficulty in understanding why the character is
stable. Utility is not the only principle that can
lead to stability : any other principle must do the
same, provided that it acts for a sufficient length
of time, and with a sufficient degree of uniformity,
on all the individuals of a species. This is a con-
sideration the cogency of which was clearly recog-
nized by Darwin, as the following quotations will
show. Speaking of unadaptive characters, he says
they may arise as merely

"fluctuating variations, which sooner or later become constant
through the nature of the organism and of surrounding conditions,
but not through natural selection '^^

Elsewhere we read : —

" Each of the endless variations which we see in the plumage
of our fowls must have had some efficient cause ; and if the
same cause were to act uniformly during a long series of genera-
tions on many individuals, all probably would be modified in
the same manner."

As special illustrations of this fact I may quote
the following cases from Darwin's works.

"Dr. Bachman states that he has seen turkeys raised from
the eggs of wild species, lose their metallic tints, and become
spotted in the third generation. Mr. Yarrell many years ago
informed me that the wild ducks bred in St. James' Park lost

' Darwinism, p. 138.

^ On'snn of Species, p. 176 : italics mine, as also in the following.

Characters as Adaptive and Specific. 187

their true plumage after a few generations. An excellent
observer (Mr. Hewitt) . . . found that he could not breed wild
ducks true for more than five or six generations, as they proved
so much less beautiful. The white collar round the neck of the
mallard became broader and more irregular, and white feathers
appeared in the duckling's wings &c.^ "

Now, such cases — to whicli numberless others might
be added — prove that even the subtle and incon-
spicuous causes incidental to domestication are
capable of inducing changes of specific character
quite as great, and quite as '-stable," as any that
in a state of nature are taken to constitute specific
distinctions. Yet there can here be no suggestion
of utility, inasmuch as the change takes place in the
course of a few generations, and therefore without
leaving time for natural selection to come into play —
even if it ever could come into play among the
sundry domesticated birds in question.

But the facts of domestication also make for the
same conclusion in another way — namely, by proving
that when time enough has been allowed for the pro-
duction of useless changes of greater magnitude,
such changes are not infrequently produced. And
the value of this line of evidence is that, great as are
the changes, it is impossible that either natural or
artificial selection can have been concerned in their
production. It will be sufficient to give two examples
— both with regard to structure.

The first I will render in the words whereby it
has already been stated in my own paper on
Physiological Selection, because I should like to take
this opportunity of answering Mr. Wallace's objection
to it.

* Var, vol. ii. p. 250.

i88 Darwin^ and after Darwin.

"Elsewhere {Origin of Species^ p. 158) Mr. Darwin points out
that modifications which appear to present obvious utility are
often found on further examination to be really useless. This
latter consideration, therefore, may be said to act as a foil to
the one against which I am arguing, namely, that modifications
which appear to be useless may nevertheless be useful. But
here is a stiil more suggestive consideration, also derived from
Mr. Darwin's writings. Among our domesticated productions
changes of structure— or even structures wholly new— not unfre-
quently arise, which are in every way analogous to the apparently
useless distinctions between wild species. Take, for example,
the following most instructive case : —

Fig. 2. — Old Irish Pig, showing jaw-appendages (after Richardson).

" ' Another curious anomaly is offered by the appendages
described by M. Eudes-Deslongchamps as often characterizing
the Normandy pigs. These appendages are always attached
to the same spot, to the corners of the jaws ; they are cylindrical,
about three inches in length, covered with bristles, and with
a pencil of bristles rising out of a sinus on one side ; they have
a cartilaginous centre with two small longitudinal muscles;
they occur either symmetrically on both sides of the face,
or on one side alone. Richardson figures them on the gaunt
old Irish Greyhound pig; and Nathusius states that they

Characters as Adaptive and Specific. 189

occasionally appear in all the long-eared races, but are not
strictly inherited, for they occur or fail in the animals of the
same litter. As no wild pigs are known to have analogous
appendages, we have at present no reason to suppose that their
appearance is due to reversion ; and if this be so, we are forced
to admit that a somewhat complex, though apparently useless,
structure may be suddenly developed without the aid of
selection *.' "

To this case Mr. Wallace objects : —

"But it is expressly stated that they are not constant ; they
appear 'frequently' or 'occasionally,' they are 'not strictly
inherited, for they occur or fail in animals of the same litter ' ;
and they are not always symmetrical, sometimes appearing on
one side of the face alone. Now, whatever may be the cause
or explanation of these anomalous appendages, they cannot be
classed with ' specific characters/ the most essential features
of which are, that they are symmetrical, that they are inherited,
and that they are constant ^."

But, to begin with, I have not classed these ap-
pendages with "specific characters," nor maintained
that Normandy pigs ought to be regarded as specifi-
cally distinct on account of them. What I said
was: —

" Now, if any such structure as this occurred in a wild species,
and if any one were to ask what is the use of it, those who rely
on the argument from ignorance would have a much stronger
case than they usually have ; for they might point to the
cartilage supplied with muscles, and supporting a curious
arrangement of bristles, as much too specialized a structure to
be wholly meaningless. Yet we happen to know that this
particular structure is wholly meaningless V

* Variation, &c. vol. i. pp. 78-79. ' Darwinism^ pp. 139-40.

' Mr. Wallace deems the concluding words "rather confident.**
I was not, however, before aware that he extended his a priori views on

190 Darwifij and after Darwin.

In the next place, is it either fair or reasonable to
expect that a varietal character of presumably very-
recent origin should be as strongly inherited — and
therefore as constant both in occurrence and sym-
metry— as a true specific character, say, of a thousand
times its age? Even characters of so-called " constant
varieties *' in a state of nature are usually less constant
than specific characters; while, again, as Darwin
says, " it is notorious that specific characters are
more variable than generic," — the reason in both
cases being, as he proceeds to show, that the less
constant characters are characters of more recent
origin, and therefore less firmly fixed by heredity \
Hence I do not understand how Mr. Wallace can
conclude, as he does, " that, admitting that this peculiar
appendage is wholly useless and meaningless, the fact
would be rather an argument against specific charac-
ters being also meaningless^ because the latter never
have the characteristics [i.e. inconstancy of occur-
rence, form, and transmission] which this particular
variation possesses'-^." Mr. Wallace can scarcely
suppose that when specific characters first arise,
they present the three-fold kind of constancy
to which he here alludes. But, if not, can it be
denied that these peculiar appendages appear to
be passing through a phase of development which
all '* specific characters " must have passed through,

utility to domesticated varieties which are bred for the slaughter-
house. If he now means to indicate that these appendages are possibly
due to natural selection, he is surely going very far to save his
a priori dogma ; and in the case next adduced will have to go further
still.

^ Origin of Species, pp. 122-3.

■^ Darwinism^ p. 140.

Characters as Adaptive and Specific, 191

before they have had time enough to be firmly
fixed by heredity ^ ?

If, however, even this should be denied, what
will be said of the second case, that of the niata
cattle ?

" I saw two herds on the northern bank of the Plata. . . . The
forehead is very short and broad, with the nasal end of the skull,
together with the whole plane of the upper molar- teeth, curved
upwards. The lower jaw projects beyond the upper, and has
a corresponding upward curvature. . . . The skull which I pre-
sented to the College of Surgeons has been thus described
by Professor Owen. ' It is remarkable from the stunted develop-
ment of the nasals, premaxillaries, and fore part of the lower
jaw, which is unusually curved upwards to come into contact
with the premaxillaries. The nasal bones are about one-third
the ordinary length, but retain almost their normal breadth.
The triangular vacuity is left between them and the frontal
and lachrymal, which latter bone articulates with the pre-
maxillary, and thus excludes the maxillary from any junction

* In the next paragraph Mr. Wallace says that the appendages in
question "are apparently of the same nature as the * sports' that arise
in our domesticated productions, but which, as Mr. Darwin says,
without the aid of selection would soon disappear." But I cannot
find that Mr. Darwin has made any such statement: what he does
say is, that whether or not a useless peculiarity will soon disappear
without the aid of selection depends upon ih^ nature of the causes which
produce it. If these causes are of a merely transitory nature, the
peculiarity will also be transitory ; but if the causes be constant, so will
be the result. Again, the point to be noticed about this " sport " is,
that, unlike what is usually imderstood by a "sport," it affects a whole
race or breed, is transmitted by sexual propagation, and has already
attained so definite a size and structure, that it can only be reasonably
accounted for by supposing the continued operation of some constant
cause. This cause can scarcely be correlation of growth, since closely
similar appendages are often seen in so different an animal as a
goat. Here, also, they run in breeds or strains, are strongly inherited,
and more "constant," as well as more " symmetrical " than they are
in pigs. This, at all events, ii the account I have received of them
from goat- breeders in Switzerland.

192 Darwin, and after Darwin,

^nJi^L, Of' Wii^D WJ/iTe: Ox

"gr- 3— ^rawn from nature. R. Coll. Surg. Mus

Characters as Adaptive and Specific, 193

with the nasal.* So that even the connexion of some of the
bones is changed. Other differences might be added : thus the
plane of the condyles is somewhat modified,' and the terminal
edge of the premaxillaries forms an arch. In fact, on comparison
with the skull of a common ox, scarcely a single bone presents
the same exact shape, and the whole skull has a wonderfully
different appearance \*'

As I cannot find that this remarkable skull has
been figured before, I have had the accompanying
woodcut made in order to compare it with the
skull of a Charsley Forest ox ; and a glance is suffi-
cient to show what " a wonderfully different appear-
ance " it presents.

Now the important points in the present connexion
with regard to this peculiar race of cattle are the
following.

Their origin is not known ; but it must have been
subsequent to the year 1552, when cattle were first
introduced to America from Europe, and it is known
that such cattle have been in existence for at least
a century. The breed is very true, and a niata bull
and cow invariably produce niata calves. A niata
bull crossed with a common cow, and the reverse
cross, yield offspring having an intermediate character,
but with the niata peculiarities highly conspicuous ^.

Here, then, we have unquestionable evidence of
a whole congeries of very distinctive characters, so
unlike anything that occurs in any other cattle,
that, had they been found in a state of nature,
they would have been regarded as a distinct

* J^arwin, Variation, &c., vol. i. pp. 93-4.
' Ibid. p. 94.

II. O

194 Darwin, and after Darwin.

species. And the highly peculiar characters which
they present conform to all "the most essential
features of specific characters," as these are stated
by Mr. Wallace in his objection to the case of the
pig's appendages. That is to say, "they are sym-
metrical, they are inherited, and they are constant."
In point of fact, they are always " constant," both as
to occurrence and symmetry, while they are so
completely " inherited " that not only does " a niata
bull and cow invariably produce niata calves " ; but
even when crossed with other cattle the result is a
hybrid^ " with the niata character strongly displayed."

Hence, if we were to follow Mr. Wallace's criteria
of specific characters, which show that the pig's
appendages "cannot be classed with specific char-
acters " (or with anything of the nature of specific
characters), it would follow that the niata peculiarities
can be so classed. This, therefore, is a case where
he will find all the reasons which in other cases
he takes to justify him in falling back upon the
argument from ignorance. The cattle are half
wild, he may urge ; and so the three- fold con-
stancy of their peculiar characters may very well
be due, either directly or indirectly, to natural
selection — i.e. they may either be of some hidden
use themselves, or correlated with some other modi-
fications that are of use : it is, he may say, as in
such cases he often does say, for us to disprove both
these possibilities.

Well, here we have one of those rare cases where
historical information, or other accidents, admit of
our discharging this burden of proving a negative.
Darwin's further description shows that this custom-

Characters as Adaptive and Specific. 195

ary refuge in the argument from ignorance is most
eflfectually closed. For —

"When the pasture is tolerably long, these cattle feed as well
as common cattle with their tongue and palate ; but during the
great droughts, when so many animals perish on the Pampas,
the niata breed lies under a great disadvantage, and would,
if not attended to, become extinct ; for the common cattle, like
horses, are able to keep alive by browsing with their lips on the
twigs of trees and on reeds ; this the niatas cannot so well do,
as their lips do not join, and hence they are found to perish
before the common cattle. This strikes me as a good illus-
tration of how little we are able to judge from the ordinary
habits of an animal, on what circumstances, occurring only at
long intervals of time, its rarity or extinction may depend.
It shows us, also, how natural selection would have determined
the rejection of the niata modification, had it arisen in a state
of nature ^"

Hence, it is plainly impossible to attribute this
modification to natural selection, either as acting
directly on the modified parts themselves, or indi-
rectly through correlation of growth. And as the
modification is of specific magnitude on the one
hand, while it presents all " the most essential fea-
tures of specific characters " on the other, I do not
see any means whereby Mr. Wallace can meet it
on his a priori principles. It would be useless to
answer that these characters, although conforming to
all his tests of specific characters, differ in respect
of being deleterious, and would therefore lead to ex-
termination were the animals in a wholly wild state ;
because, considered as an argument, this would involve
the assumption that, apart from natural selection,
only deleterious characters can arise under nature

^ Darwin, Variation ':c. voL i. p. 94.
O 2

196 DarwiUy and after Darwin.

— i. e. that merely '' indifferent" characters can never
do so, which would be absurd. Indeed, I have chosen
this case of the niata cattle expressly because their
strongly marked peculiarities are deleterious, and
therefore exclude Mr. Wallace's appeal to the argu-
ment from ignorance of a possible utility. But if even
these pronounced and deleterious peculiarities can
arise and be perpetuated with such constancy and
fidelity, much more is this likely to be the case with
less pronounced and merely neutral peculiarities.

It may, however, be further objected that these
cattle are not improbably the result of artificial selec-
tion. It may be suggested that the semi-monstrous
breed originated in a single congenital variation, or
"sport," which was isolated and multiplied as a
curiosity by the early settlers. But even if such be the
explanation of this particular case, the fact would
not weaken our illustration. On the contrary, it
would strengthen our general argument, by showing an
additional means whereby indifferent specific charac-
ters can arise and become fixed in a state of nature.
As it seems to me extremely probable that the niata
cattle did originate in a congenital monstrosity, which
was then isolated and multiplied by human agency
(as is known to have been the case with the " ancon
sheep"), I will explain why this tends to strengthen
our general argument.

It is certain that if these animals were ever subject
to artificial isolation for the purpose of establishing
their breed, the process must have ceased a long time
ago, seeing that there is no memory or tradition of
its occurrence. Now this proves that, however the
breed may have originated, it has been able to main-

Characters as Adaptive and Specific. 197

tain its many and highly peculiar characters for a
number of generations without the help of selection,
either natural or artificial. This is the first point to
be clear upon. Be its origin what it may, we know
that this breed has proved capable of perpetuating
itself with uniform "constancy" for a number of
generations after the artificial selection has ceased —
supposing such a process ever to have occurred. And
this certain fact that artificial selection, even if it
was originally needed to establish the type, has not
been needed to perpetuate the type, is a full answer
to the supposed objection. For, in view of this fact, it
is immaterial what the origin of the niata breed may
have been. In the present connexion, the importance
of this breed consists in its proving the subsequent
" stability " of an almost monstrous form, continued
through a long series of generations by the force
of heredity alone, without the aid of any form of
selection.

The next point is, that not only is a seeming
objection to the illustration thus removed, but that,
if we do entertaiij the question of origin, and if we
do suppose the origin of these cattle to have been
in a congenital *' sport," afterwards multiplied by
artificial isolation, we actually strengthen our general
argument by increasing the importance of this par-
ticular illustration. For the illustration then becomes
available to show how indifferent specific characters
may sometimes originate in merely individual sports,
which, if not immediately extinguished by free
intercrossing, will perpetuate themselves by the
unaided force of heredity. But this is a point to which
we shall recur in the ensuing chapter.

198 Darwin^ and after Darwin.

In conclusion, it is worth while to remark, with
regard to Mr. Wallace's argument from constancy,
that, as a matter of fact, utility does not seem to
present any greater power in securing " stability of
characters " than any other cause of like constancy
Thus, for instance, whatever the causes may liave
been which have produced and perpetuated the niata
breed of cattle, they have certainly produced a won-
derful " stability " of a great modification in a wonder-
fully short time. And the same has to be said of the
ducks in St. James' Park, as well as sundry other cases.
On the other hand, when, as in the case of numberless
natural species, modification has been undoubtedly
produced by natural selection, although the modifica-
tion must have had a very much longer time in which
to have been fixed by heredity, it is often far from
being stable — notwithstanding that Mr. Wallace
regards stability as a criterion of specific characters.
Indeed — and this is more suggestive still — there even
seems to be a kind of inverse proportion between the
utility and the stability of a specific character. The ex-
planation appears to be ( Origin of Species, pp. 1 20-2),
that the more a specific character has been forced on
by natural selection on account of its utility, the less
time will it have had to become well fixed by heredity
before attaining a full development. Moreover, as
Darwin adds, in cases where the modification has
not only been thus " comparatively recent.' but also
'* extraordinarily great," the probability is that the
parts so modified must have been very variable in the
first instance, and so are all the more difficult to
render constant by heredity. Thus we see that utility
is no better— even if it be so good — a cause of

Characters as Adaptive and Specific. 199

stability in specific characters, as are the unlvnown
causes of stability in many varietal characters ^.

* Should it be objected that useless characters, according to my own
view of the Cessation of Selection, ought to disappear, and therefore
cannot be constant, the answer is evident For, by hypothesis, it is only
those useless characters which were at one time useful that disappear
under this principle. Selection cannot cease unless it Was previously present
— i.e. save in cases where the now useless character was originally due
to selection. Hence, in all cases where it was due to any other cause, the
useless character will persist at least as long as its originating cause
continues to operate. And even after the latter (whatever it may be)
has ceased to operate, the useless character will but slowly degenerate,
until the eventual failure of heredity causes it to disappear in toto — long
before which time it may very well have become a generic, or some higher,
character.

CHAPTER VIII.

Characters as Adaptive and Specific
(continued).

Let us now proceed to indicate some of the
causes, other than natural selection, which may be
regarded as adequate to induce such changes in
organic types as are taken by systematists to con-
stitute diagnostic distinctions between species and
species. We will first consider causes external to
organisms, and will then go on to consider those which
occur within the organisms themselves : following, in
fact, the classification which Darwin has himself laid
down. For he constantly speaks of such causes as
arising on the one hand, from * changed conditions of
Hfe " and, on the other hand, from '* the nature of the
organism "—that is, from internal processes leading
to "variations which seem to us in our ignorance to
arise spontaneously."

In neither case will it be practicable to give more
than a brief resum^ of all that might be said on these
interesting topics.

I. Climate,

There is an overwhelming mass of evidence to
prove that the assemblage of external conditions of
life conveniently summarized in the word Climate,

Characters as Adaptive and Specific. 201

exercise a potent, an uniform, and a permanent in-
fluence on specific characters.

With regard to plants, Darwin adduces a number
of facts to show the effects of climate on wheat,
cabbages, and other vegetables. Here, for example,
is what he says with regard to maize imported
from America to Germany : —

" During the first year the plants were twelve feet high, and
a few seeds were perfected ; the lower seeds in the ear kept
true to their proper form, but the upper seeds became slightly
changed. In the second generation the plants were from nine
to ten feet high, and ripened their seed better ; the depression
on the outer side of the seed had almost disappeared, and the
original beautiful white colour had become duskier. Some
of the seeds had even become yellow, and in their now rounded
form they approached the common European maize. In the
third generation nearly all resemblance to the original and very
distinct American parent-form was lost '."

As these '• highly remarkable " changes were effected
in but three generations, it is obvious that they
cannot have been dependent on selection of any
kind. The same remark applies to trees. Thus, —

" Mr. Meehan has compared twenty-nine kinds of American
trees with their nearest European allies, all grown in close
proximity and under as nearly as possible the same conditions.
In the American species he finds, with the rarest exceptions,
that the leaves fall earlier in the season, and assume before their
fall a brighter tint ; that they are less deeply toothed or serrated ;
that the buds are smaller ; that the trees are more diffuse in
growth and have fewer branchlets ; and, lastly, that the seeds
are smaller — all in comparison with the corresponding European
species. Now, considering that these corresponding trees

* Variation, 8cc. vol. i. p. 340.

202 DarwiUy and after Darwin,

belong to several distinct orders, and that they are adapted to
widely different stations, it can hardly be supposed that their
differences are of any special service to them in the New and
Old worlds ; and, if so, such differences cannot have been gained
through natural selection, and must be attributed to the long
continued action of a different climate ^."

These cases, however, I quote mainly in order to
show Darwins opinion upon the matter, with reference
to the absence of natural selection. For, where the
vegetable kingdom is concerned, the fact of climatic
variation is so general, and in its relation to diag-
nostic work so important, that it constitutes one of
the chief difficulties against which species-makers
have to contend. And the more carefully the subject
is examined the greater does the difficulty become.
But, as to this and other general facts, it will be
best to allow a recognized authority to speak ; and
therefore I will give a few extracts from Kerner's
work on Gute und schlechte Arten.

He begins by showing that geographical (or it
may be topographical) varieties of species are often
so divergent, that without a knowledge of intermediate,
forms there could be no question as to their being
good species. As a result of his own researches on
the subject^ he can scarcely find language strong
enough to express his estimate of the extent and
the generality of this source of error. In different
parts of Europe, or even in different parts of the
Alps, he has found these climatic varieties in such
multitudes and in such high degrees both of con-
stancy and divergence, that, after detailing his results,

* Variation^ &c. vol. ii. p. 271.

Characters as Adaptive and Specific. 203

he finishes his essay with the following remarkable
conclusions : —

" Die Wissenchaft geht aber ihren Entwicklungsgang im
grosser! Ganzen gerade so, wie die Erkenntniss bei jedem einzel-
nen Naturforscher. Fast jeder Botaniker muss seinen Entwick-
lungsgang durChmachen und gelangt endlich mehr oder weniger
nahe zu demselben Ziele. Die Ungleichheit besteht nur darin,
dass der eine langsamer, der andere aber rascher bei dem Ziele
ankommt. Anfanglich miiht sich jeder ab, die Formen in
hergebrachter Weise zu gliedern und die 'guten Arten' herauszu-
lesen. Mit der Erweiterung des Gesichtskreises und mit der
Vermehrung der Anschauungen aber schwindet auch immer
mehr der Boden unter den Fiissen, die bisher fiir unverriickbar
gehaltenen Grenzen der gut geglaubten Arten stellen sich als
eine der Natur angelegte Zwangsjacke heraus, die Ueberzeugung,
dass die Grenzen, weiche wir ziehen, eben nur kiinstliche sind,
gewinnt immer mehr und mehr die Oberhand, und wer nicht
gerade zu den hartgesottenen Eigensinnigen gehort, und wer
die Wahrheit hoher stellt als das starre Festhalten an seinen
friiheren Ansichten, geht schliesslich bewusst oder unbewusst
in das Lager derjenigen iiber, in welchem auch ich mir ein
bescheidenes Platzchen aufgesucht habe."

By these "hard-boiled" botanists he means those
who entertain the traditional notion of a species as
an assemblage of definite characters, always and
everywhere associated together. This notion (Arts-
bestandigkeit) must be entirely abandoned. Sum-
marizing Kerner^s facts for their general results we find
that his extensive investigations have proved that in
his numberless kinds of European plants the following
relations frequently obtain. Supposing that there are
two or more allied species, A and B, then A' and B'
may be taken to represent their respective types as
found in some particular area. It does not signify

204 Darwifiy and after Darwin,

whether A' and B' are geographically remote from,
or close to, A and B ; the point is that, whether in
respect of temperature, altitude, moisture, character
of soil, &c., there is some difference in the conditions
of life experienced by the plants growing at the dif-
ferent places. Now, in numberless plants it is found
that the typical or constant peculiarities of A' differ
more from those of A than they do from those of B ;
while, conversely, the characters of A' may bear more
resemblance to those of B' than they do to those
of A — on account of such characters being due to
the same external causes in both cases. The conse-
quence is that A' might more correctly be classified
with B', or vice versa. Another consequence is that
whether A and B, or A' and B', be recorded as the
"good species" usually depends upon which has
happened to have been first described.

Such a mere abstract of Kerner's general results,
however, can give no adequate idea of their cogency :
for this arises from the number of species in which
specific characters are thus found to change, and even to
interchange, with different conditions of life. Thus he
gives an amusing parable of an ardent young botanist,
Simplicius, who starts on a tour in the Tyrol with
the works of the most authoritative systematists to
assist him in his study of the flora. The result is
that Simplicius becomes so hopelessly bewildered in
his attempts at squaring their diagnostic descriptions
with the facts of nature, that he can only exclaim
in despair — '* Sonderbare Flora, diese tirolische, in
welcher so viele characteristische Pflanzen nur
schlechte Arten, oder gar noch schlechter als schlechte
Arten, sind." Now, in giving illustrations of this

Characters as Adaptive and Specific. 205

young man's troubles, Kerner fills five or six pages
with little else than rows of specific names.

Upon the whole, Kerner concludes that the more
the subject is studied, the more convinced must the
student become that all distinction between species as
" good " and " bad " vanishes. In other words, the more
that our knowledge of species and of their diagnostic
characters increases, the more do we find that " bad
species" multiply at the expense of " good species" ; so
that eventually we must relinquish the idea of "good
species'* altogether. Or, conversely stated, we must
agree to regard as equally "good species^' any and
every assemblage of individuals which present the
same peculiarities : provided that these peculiarities
do not rise to a generic value, they equally deserve
to be regarded as "specific characters," no matter
how trivial, or how local, they may be. In fact, he
goes so far as to say that when, as a result of
experiments in transplantation from one set of
physical conditions to another, seedlings are found
to present any considerable and constant change in
their specific characters, these seedlings are no less
entitled to be regarded as a "' good species " than
are the plants from which they have been derived.
Probably few systematists will consent to go quite
so far as this ; but the fact that Kerner has been
led deliberately to propound such a statement as
a result of his wide observations and experiments
is about as good evidence as possible on the
points with which we are here concerned. For even
Simplicius would hardly be quite so simple as to
suppose that each one of all the characters which
he observes in his " remarkable flora," so largely

2o6 Darwin^ and after Darwin,

composed of "bad or even worse than bad species,"
is of utilitarian significance.

Be it noted, however, that I am not now ex-
pressing my own opinion. There are weighty reasons
against thus identifying climatic variations with
good species — reasons which will be dealt with
in the next chapter. Kerner does not seem to
appreciate the weight of these reasons, and therefore
I do not call him as a witness to the subject as
a whole ; but only to that part of it which has to do
with the great and general importance of climatic
variability in relation to diagnostic work. And thus
far his testimony is fully corroborated by every other
botanist who has ever attended to the subject.
Therefore it does not seem worth while to quote
further authorities in substantiation of this point, such
as Gartner, De CandoUe, Nageli, Peter, Jordan, &c.
For nowadays no one will dispute the high generality
and the frequently great extent of climatic variation
where the vegetable kingdom is concerned. Indeed,
it may fairly be doubted whether there is any one
species of plant, whose distribution exposes it to any
considerable differences in its external conditions of
life, which does not present more or less considerable
differences as to its characters in different parts of its
range. The principal causes of such climatic variation
appear to be the chemical; and, still more, the
mechanical nature of soil ; temperature ; intensity and
diurnal duration of light in spring and summer;
moisture ; presence of certain salts in the air and soil
of marine plants, or of plants growing near mineral
springs ; and sundry other circumstances of a more
or less unknown character.

Characters as Adaptive and Specific. 207

Before closing these remarks on climatic variation in
the vegetable kingdom, prominent attention must be
directed to a fact of broad generality and, in relation
to our present subject, of considerable importance.
This is that the same external causes very frequently
produce the same effects in the way of specific change
throughout large numbers of unrelated species — i. e.
species belonging to different genera, families, and
orders. Moreover, throughout all these unrelated
species, we can frequently trace a uniform correlation
between the degrees of change and the degrees to
which they have been subjected to the causes in
question.

As examples, all botanists who have attended to
the subject are struck by the similarity of variation
presented by different species growing on the same
soils, altitudes, latitudes, longitudes, and so forth.
Plants growing on chalky soils, when compared with
those growing on richer soils, are often more thickly
covered with down, which is usually of a white or
grey colour. Their leaves are frequently of a bluish-
green tint, more deeply cut, and less veined, while
their flowers tend to be larger and of a lighter
tint. There are similarly constant differences in
other respects in varieties growing on sundry other
kinds of soils. Sea-salt has the general effect, on
many different kinds of plants, of producing moist
fleshy leaves, and red tints. Experiments in trans-
plantation have shown that these changes may be
induced artificially ; so there can be no doubt as to its
being this that and the other set of external conditions
which produces them in nature. Again, dampness
causes leaves to become smoother, greener, less cut,

2o8 Darwin^ and after Darwin,

and the flowers to become darker ; while dryness
tends to produce opposite effects. I need not go on
to specify the particular results on all kinds of plants
of altitude, latitude, longitude, and so forth. For we
are concerned only with the fact that these two
correlations may be regarded as general laws apper-
taining to the vegetable kingdom— namely, (A) that
the same external causes produce similar varietal
effects in numerous unallied species of plants; and
(B) that the more these species are exposed to such
causes the greater is the amount of varietal effect
produced— so that, for instance, on travelling from
latitude to latitude, longitude to longitude, altitude
to altitude, &c., we may see greater and greater
degrees of such definite and more or less common
varietal changes affecting the unallied species in
question. Now these general laws are of importance
for us, because they prove unequivocally that it is the
direct action of external conditions of life which
produce climatic variations of specific types. And,
taken in connexion with the results of experiments in
transplantation (which in a single generation may
yield variations similar to those found in nature under
similar circumstances), these general laws still further
indicate that climatic variations are " indifferent "
variations. In other words, we find that changes of
specific characters are of widespread occurrence in the
vegetable kingdom, that they are constantly and even
proportionally related todefiniteexternal circumstances,
but yet that, in as far as they are climatic, they can-
not be attributed to the agency of natural selection ^

^ Since the above paragraphs have been in type, the Rev. G. Henslow
has published his Linnacan Society papers which are mentioned in the

Characters as Adaptive and Specific. 209

Turning next to animals, it may first be observed
that climatic conditions do not appear to exercise
an influence either so general or so considerable
as in the case of plants. Nevertheless, although
these influences are relatively more effective in the
vegetable kingdom than they are in the animal,
absolutely considered they are of high generality and
great importance even in the latter. But as this
fact is so well recognized by all zoologists, it will
be needless to give more than a very few illustrations.
Indeed, throughout this discussion on climatic in-
fluences my aim is merely to give the general reader
some idea of their importance in regard to system-
atic natural history ; and, therefore, such particular
cases as are mentioned are selected only as samples
of whole groups of cases more or less similar.

With regard to animals, then, we may best begin
by noticing that, just as in the case of plants, there is
good evidence of the same external causes producing
the same effects in multitudes of species belonging
to different genera, families, orders, and even classes.
Moreover, we are not without similarly good evidence
of ^^^r^^i of specific change taking place in correlation
with degrees of climatic change, so that we may
frequently trace a gradual progress of the former as
we advance, say, from one part of a large continent
to another. Instances of these correlations are
not indeed so numerous in the animal kingdom as
they are in the vegetable. Nevertheless they are
amply sufficient for our present purposes.

For example, Mr. Allen has studied in detail

introductory chapter, and which deal in more detail with this subject,
especially as regards the lacies of desert flora*.

II. P

2IO DarwiUy and after Darwin,

changes of size and colour among birds and mammals
on the American continent ; and he finds a won-
derfully close sliding scale of both, corresponding
stage by stage with gradual changes of climate.
Very reasonably he attributes this to the direct
influence of climatic conditions, without reference
to natural selection — as does also Mr. Gould with
reference to similar facts which he has observed
among the birds of Australia. Against this view
Mr. Wallace urges, " that the effects are due to the
greater or less need of protection." But it is difficult
to believe that such can be the case where so in-
numerable a multitude of widely different species
are concerned — presenting so many diverse habits,
as well as so many distinct habitats. Moreover, the
explanation seems incompatible with the graduated
nature of the change, and also with the fact that not
only colouration but size, is implicated.

We meet with analogous facts in butterflies.
Thus Lycaena agestis not only presents seasonal
variations, (A) and (B); but while (A) and (B) are
respectively the winter and summer forms in
Germany, (B) and (C) are the corresponding forms
in Italy. Therefore, (B) is in Germany the summer
form, and in Italy the winter form — the German
winter form (A) being absent in Italy, while the
Italian summer form (C) is absent in Germany.
Probably these facts are due to differences of tem-
perature in the two countries, for experiments have
shown that when pupae of sundry species of moths
and butterflies are exposed to different degrees of
temperature, the most wonderful changes of colour
may result in the insects which emerge. The re-

Characters as Adaptive and Specific. 211

markable experiments of Dorfmeister and Weismann
in relation to this subject are well known. More
recently Mr. Merrifield has added to their facts, and
concludes that the action of cold upon the pupae —
and also, apparently, upon the larvae — has a tendency
to produce dark hues in the perfect insect^.

But, passing now from such facts of climatic vari-
ations over wide areas to similar facts within small
areas, in an important Memoir on the Cave Fauna
of North America, published a few years ago by the
American Academy of Sciences, it is stated : —

** As regards change of colour, we do not recall an exception to
the general rule that all cave animals are either colourless or
nearly white, or, as in the case of Arachnida and Insects, much
paler than their out-of-door relatives."

Now, when we remember that these cave faunas
comprise representatives of nearly all classes of the
animal kingdom, it becomes difficult, if not impos-
sible, to imagine that so universal a discharge of
colouring can be due to natural selection. It must
be admitted that the only way in which natural
selection could act in this case would be indirectly
through the principle of correlation. There being no
light in the caves, it can be of no advantage to the
animals concerned that they should lose their colour
for the sake of protection, or for any other reason of
a similarly direct kind. Therefore, if the loss of colour
is to be ascribed to natural selection, this can only
be done by supposing that natural selection has here
acted indirectly through the principle of correlation.
There is evidence to show that elsewhere modification

^ Trans. Entom. Soc. 1889, P^^ 1* P* 79 ^^ ^^9*

p a

2x2 Darwm, and after Darwin,

or loss of colour is in some cases brought about by
natural selection, on account of the original colour
being correlated with certain physiological characters
(such as liability to particular diseases, &c.) ; so that
when natural selection operates directly upon these
physiological characters, it thereby also operates
indirectly upon the correlated colours. But to suppose
that this can be the explanation of the uniform
diminution of colour in all inhabitants of dark caves
would be manifestly absurd. If there were only one
class of animals in these caves, such as Insects, it
might be possible to surmise that their change of
colour is due to natural selection acting directly upon
their physiological constitutions, and so indirectly
upon their colours. But it would be absurd to
suppose that such can be the explanation of the
facts, when these extend in so similar a manner over
so many scores of species belonging to such different
types of animal life. t

With more plausibility it might be held that the
universal discharge of colour in these cave-faunas
is due, not to the presence, but to the absence of
selection — i.e. to the cessation of selection, or pan-
mixia. But against this — at all events, as a full or
general explanation — lie the following facts. First,
in the case of Proteus — which has often been kept
for the purposes of exhibition &c., in tanks — the skin
becomes dark when the animal is removed from the
cave and kept in the light. Secondly, deep-sea faunas,
though as much exposed as the cave-faunas, to the
condition of darkness, are not by any means invariably
colourless. On the contrary, they frequently present
brilliant colouration. Thus it is evident that if pan-

i

Characters as Adaptive and Specific, 213

mixia be suggested in explanation of the discharge
of colouring in cave-faunas, the continuance of colour
in deep-sea faunas appears to show the explanation
insufficient. Thirdly, according to my view of the
action of panmixia as previously explained, no total
discharge of colouration is likely to be caused by such
action alone. At most the bleaching as a result
of the mere withdrawal of selection would proceed
only to some comparatively small extent. Fourthly,
Mr. Packard in the elaborate Memoir on Cave
Fauna, already alluded to, states that in some of
the cases the phenomena of bleaching appear to have
been induced within very recent times — if not, indeed,
within the limits of a single generation. Should
the evidence in support of this opinion prove trust-
worthy, of course in itself it disposes of any sugges-
tion either of the presence or the* absence of natural
selection as concerned in the process.

Nevertheless, I myself think it inevitable that to
some extent the cessation of selection must have
helped in discharging the colour of cave faunas;
although for the reasons now given it appears to me
that the main causes of change must have been of
that direct order which we understand by the term
climatic.

As regards dogs, the Rev. E. Everest found it impos-
sible to breed Scotch setters in India true to their type.
Even in the second generation no single young dog
resembled its parents either in form or shape. " Their
nostrils were more contracted, their noses more pointed,
their size inferior, and their limbs more slender ^"
Similarly on the coast of New Guinea, Bodsman says

* yariation, &c. vol. i. p. 40.

214 Darwin^ and after Darwin.

that imported breeds of dogs '* alter strangely ; their
ears grow long and stiff like those of foxes, to which
colour they also incline . . . and in three or four
broods their barking turns into a howl ^"

Darwin gives numerous facts showing the effects of
climate on horses, cattle, and sheep, in altering, more
or less considerably, the characters of their ancestral
stocks. He also gives the following remarkable case
with regard to the rabbit. Early in the fifteenth
century a common rabbit and her young ones were
turned out on the island of Porto Santo, near Madeira.
The feral progeny now differ in many respects from
their parent stock. They are only about one-third of
the weight, present many differences in the relative
sizes of different parts, and have greatly changed in
colour. In particular the black on the upper surface
of the tail and tips of the ears, which is so constant
in all other wild rabbits of the world as to be given
in most works as a specific character, has entirely
disappeared. Again, " the throat and certain parts of
the under surface, instead of being pure white, are
generally grey or leaden colour/' while the upper
surface of the whole body is redder than in the
common rabbit. Now, what answer have our op-
ponents to make to such a case as this ? Presumably
they will answer that the case simply proves the
action of natural selection during the best part of 400
years on an isolated section of a species. Although
we cannot say of what use all these changes have
been to the rabbits presenting them, nevertheless we
must believe that they have been produced by natural
selection, and therefore must present some hidden use

' Variation, &c. vol. i. p. 40.

Characters as Adaptive and Specific. 215

to the isolated colony of rabbits thus peculiarly
situated. Four centuries is long enough to admit of
natural selection effecting all these changes in the case
of so rapidly breeding an animal as the rabbit, and there-
fore it is needless to look further for any explanation
of the facts. Such, I say, is presumably the answer
that would be given by the upholders of natural
selection as the only possible cause of specific change.
But now, in this particular case it so happens that
the answer admits of being conclusively negatived,
by showing that the great assumption on which it
reposes is demonstrably false. For Darwin examined
two living specimens of these rabbits which had
recently been sent from Porto Santo to the Zoo-
logical Gardens, and found them coloured as just
described. Four years afterwards the dead body
of one of them was sent to him, and then he found
that the following changes had taken place. " The ears
were plainly edged, and the upper surface of the tail
was covered with blackish-grey fur, and the whole
body was much less red ; so that under the English
climate this individual rabbit has recovered the proper
colour of its fur in rather less than four years 1 "

Mr. Darwin adds : —

"If the history of these Porto Santo rabbits had not been
known, most naturalists, on observing their much reduced size,
their colour, reddish above and grey beneath, their tails and
ears not tipped with black, would have ranked them as a
distinct species. They would have been strongly confirmed in
this view by seeing them alive in the Zoological Gardens, and
hearing that they refused to couple with other rabbits. Yet this
rabbit, which there can be little doubt would thus have been
ranked as a distinct species, as certainly originated since the
year 1420 \

* Variation, &c. vol. i. p. I30.

2i6 Darwin, and after Darwin.

Moreover, it certainly originated as a direct result
of climatic influences, independent of natural selection ;
seeing that, as soon as individual members of this
apparently new species were restored to their original
climate, they recovered their original colouration.

As previously remarked, it is, from the nature
of the case, an exceedingly difficult thing to prove
in any given instance that natural selection has not
been the cause of specific change, and so finally to
disprove the assumption that it must have been.
Here, however, on account of historical information,
we have a crucial test of the validity of this assump-
tion, just as we had in the case of the niata cattle ;
and, just as in their case, the result is definitely
and conclusively to overturn the assumption. If
these changes in the Porto Santo rabbits had been
due to the gradual influence of natural selection
guided by inscrutable utility, it is simply impossible
that the same individual animals, in the course of
their own individual lifetimes, should revert to the
specific characters of their ancestral stock on being
returned to the conditions of their ancestral climate.
Therefore, unless any naturalist is prepared to con-
tradict Darwin's statement that the changes in
question amount to changes of specific magnitude,
he can find no escape from the conclusion that
distinctions of specific importance may be brought
about by changes of habitat alone, without reference
to utility, and therefore independently of natural
selection.

Characters as Adaptive and Specific. 217

II. Food,

Although, as yet, little is definitely known on the
subject, there can be no doubt that in the case of
many animals differences of food induce differences
of colour within the lifetime of individuals, and
therefore independently of natural selection.

Thus, sundry definite varieties of the butterfly
Euprepia caja can be reared according to the different
nourishment which is supplied to the caterpillar ; and
other butterflies are also known on whose colouring
and markings the food of the caterpillar has great
influence \

Again, I may mention the remarkable case com-
municated to Darwin by Moritz Wagner, of a species
of Saturnia, some pupae of which were transported
from Texas to Switzerland in 1870. The moths
which emerged in the following year were like the
normal type in Texas. Their young were supplied
with leaves of Juglans regia, instead of their natural
food, J. nigra ; and the moths into which these
caterpillars changed were so different from their
parents, both in form and colour, "that they were
reckoned by entomologists as a distinct species ^.*'

With regard to moUusks, M. Costa tells us that
English oysters, when turned down in the Mediter-
ranean, " rapidly became like the true Mediterranean

' See especially, Koch, Die Kaupen und Schnutterling der Wet-
terau, and Die Schmetterling des Siidwest lichen Deiitschlands, whose very
remarkable results of numerous and varied experiments are epitomized
by Eimer, Organic Evolution, Eng. Trans, pp. 147-153 ; also Poulton,
Trans. Entom. Soc. 1893.

•■' Mivart, On Truth, p. 378.

2i8 Da^^n, and after Darwin,

oyster, altered their manner of growth, and formed
prominent diverging rays." This is most probably due
to some change of food. So likewise may be the even
more remarkable case of Helix ^ nemoralis, which was
introduced from Europe to Virginia a few years ago.
Under the new conditions it varied to such an extent
that up to last year no less than 125 varieties had
been discovered. Of these 67, or more than half,
are new — that is, unknown in the native continent ot
the species^.

In the case of Birds, the Brazilian parrot Chrysotis
festiva changes the green in its feathers to red or
yellow, if fed on the fat of certain fishes ; and the
Indian Lori has its splendid colouring .preserved by
a peculiar kind of food (Wallace). The Bullfinch
is well known to turn black when fed on hemp
seeds, and the Canary to become red when fed on
cayenne pepper (Darwin). Starting from these facts,
Dr. Sauermann has recently investigated the subject
experimentally; and finds that not only finches, but
likewise other birds, such as fowls, and pigeons, are
subject to similar variations of colour when fed on
cayenne pepper ; but in all cases the effect is pro-
duced only if the pepper is given to the young birds
before their first moult. Moreover, he finds that
a moist atmosphere facilitates the change of colour,
and that the ruddy hue is discharged under the
influence either of sunlight or of cold. Lastly, he
has observed that sundry other materials such as
glycerine and aniline dyes, produce the same results ;
so there can be no doubt that organic compounds
probably occur in nature which are capable of

* Cockerell, Nature^ vol. xli. p. 393.

Characters as Adaptive and Specific. 219

directly affecting the colours of plumage when eaten
by birds. Therefore the presence of such materials
in the food-stuffs of birds occupying different areas
may very well in many cases determine differences
of colouration, which are constant or stable so long
as the conditions of their production are maintained.

III. Sexual Selection.

Passing on now to causes of specific change which
are internal, or comprised within the organisms
themselves, we may first consider the case of Sexual
Selection.

Mr. Wallace rejects the theory of sexual selection
in toto, and therefore nothing that can be said under
this head would be held by him to be relevant.
Many naturalists, however, believe that Darwin was
right in the large generalization which he published
under this title ; and in so far as any one holds that
sexual selection is a true cause of specific modification,
he is obliged to believe that innumerable specific
characters — especially in birds and mammals — have
been produced without reference to utility (other,
of course, than utility for sexual purposes), and
therefore without reference to natural selection. This
is so obvious that I need not pause to dilate upon it.
One remark, however, may be useful. Mr. Wallace
is able to make a much more effective use of his
argument from "necessary instability" when he
brings it against the Darwinian doctrine of sexual
selection, than he does when he brings it against the
equally Darwinian doctrine of specific characters in
general not being all necessarily due to natural

220

Darwifiy and after Darwin,

selection. In the latter case, it will be remembered,
he is easily met by showing that the causes of specific
change other than natural selection, such as food,
climate, &c., may be quite as general, persistent, and
uniform, as natural selection itself; and therefore in
this connexion Mr. Wallace's argument falls to the
ground. But the argument is much more formidable
as he brings it to bear against the theory of sexual
selection. Here he asks. What is there to guarantee
the uniformity and the constancy of feminine taste
with regard to small matters of embellishment through
thousands of generations, and among animals living
on extensive areas? And, as we have seen in Part I,
it is not easy to supply an answer. Therefore this
argument from the " necessary instability of charac-
ter" is of immeasurably greater force as thus applied
against Darwin's doctrine of sexual selection, than it
is when brought against his doctrine that all specific
characters need not necessarily be due to natural
selection. Therefore, also, if any one feels disposed
to attach the smallest degree of value to this argu-
ment in the latter case, consistency will require him
to allow that in the former case it is simply over-
whelming, or in itself destructive of the whole theory
of sexual selection. And, conversely, if his belief in
the theory of sexual selection can survive collision
with this objection fram instability, he ought not to
feel any tremor of contact when the objection is
brought to bear against his scepticism regarding the
alleged utility of all specific characters. For assuredly
no specific character which is apparent to our eyes
can be supposed to be so refined and complex (and
therefore so presumably inconstant and unstable), as

Characters as Adaptive and Specific. 221

are those minute changes of cerebral structure on
which a pyschological preference for all the refined
shadings and many pigments of a complicated
pattern must be held ultimately to depend. For this
reason, then, as well as for those previously adduced,
if any one agrees with Darwin in holding to the
theory of sexual selection notwithstanding this ob-
jection from the necessary instability of unuseful
embellishments, a fortiori he ought to disregard the
objection altogether in its relation to useless specific
characters of other kinds.

But quite apart from this consideration, which
Mr. Wallace and his followers may very properly say
does not apply to them, let us see what they them-
selves have made of the facts of secondary sexual
characters — which, of course, are for the most part
specific characters — in relation to the doctrine of
utility.

Mr. Wallace himself, in his last work, quotes
approvingly a letter which he received in 1869 from
the Rev. O Pickard- Cambridge, as follows : —

" I myself doubt that particular application of the Darwinian
theory which attributes male peculiarities of form, structure,
colour, and ornament to female appetency or predilection.
There is, it seems to me, undoubtedly something in the male
organization of a special and sexual nature, which, of its own
vital force, develops the remarkable male peculiarities so
commonly seen, and of no imaginable use to that sex. In as far
as these peculiarities show a great vital power, they point out
to us the finest and strongest individuals of the sex, and show
us which of them would most certainly appropriate to themselves
the best and greatest number of females, and leave behind them
the strongest and greatest number of progeny. And here would
come in, as it appears to me, the proper application of Darwin's

222 Darwin^ and after Darwin.

theory of Natural Selection ; for the possessors of greatest vital
iiower being those most frequently produced and reproduced, thi
external signs of it would go on developing in an ever increas-
ing exaggeration^ only to be checked where it became really
detrimental in some respect or other to thq individual *."

Here then the idea is, as more fully expressed by-
Mr. Wallace in the context, that all the innumerable,
frequently considerable, and generally elaborate " pe-
culiarities of form, structure, colour, and ornament,"
which Darwin attributed to sexual selection, are really
due to *' the laws of growth." Diverse, definite, and
constant though these specific peculiarities be. they
are all but the accidental or adventitious accompani-
ments of " vigour," or '• vital power," due to natural
selection. Now, without waiting to dispute this view,
which has already been dealt with in the chapter
on Sexual Selection in Part I, it necessarily follows
that " a large proportional number of specific char-
acters," which, while presenting '*no imaginable use,"
are very much less remarkable, less considerable, less
elaborate, &c., must likewise be due to this "correlation
with vital power." But if the principle of correlation
is to be extended in this vague and general manner, it
appears to me that the difference between Mr. Wallace
and myself, with respect to the principle of utility, is
abolished. For of course no one will dispute that
the prime condition to the occurrence of "specific
characters," whether useful or useless, is the existence
of some form which has been denominated a "species"
to present them ; and this is merely another way of
saying that such characters cannot arise except in
correlation with a general fitness due to natural

^ Darwinism, pp 296-7 : italics mine.

Lharaders as Adaptive and Specific. 223

selection. Or, to put the case in Mr. Wallace's
own words — " This development [of useless specific
characters] will necessarily proceed by the agency of
natural selection [as a necessary condition] and the
general laivs which determine the production of colour
and of ornamenial appendages^ The case, therefore,
is just the same as if one were to say, for example,
that all the ailments of animals and plants proceed
from correlation with life (as a necessary condition),
"and the general laws which determine the production"
of ill-health, or of specific disease. In short, the
word " correlation " is here used in a totally different
sense from that in which it is used by Darwin, and in
which it is elsewhere used by Wallace for the purpose
of sustaining his doctrine of specific characters as
necessarily useful. To say that a useless character
A is correlated with a useful one B, is a very different
thing from saying that A is " correlated with vital
power," or with the general conditions to the exist-
ence of the species to which it belongs. So far as the
present discussion is concerned, no exception need be
taken to the latter statement. For it simply sur-
renders the doctrine against which I am contending.

IV. Isolation.

It is the opinion of many naturalists who are
well entitled to have an opinion upon the subject
that, in the words of Mr. Dixon, '• Isolation can
preserve a non-beneficial as effectually as natural
selection can preserve a beneficial variation ^" The
ground on which this doctrine rests is thu:> clearly

* Nahtrty vol. xxxiii. p. loo.

224 Darwin^ and after Darwin,

set forth by Mr. Gulick : — '* The fundamental cause
of this seems to lie in the fact that no two portions of
a species possess exactly the same average characters ;
and, therefore, that the initial differences are for
ever reacting on the environment and on each other
in such a way as to ensure increasing divergence
in each generation, as long as the individuals of
the two groups are kept from intergenerating^." In
other words, as soon as a portion of a species is
separated from the rest of that species, so that
breeding between the two portions is no longer
possible, the general average of characters in the
separated portion not being in all respects precisely
the same as it is in the other portion, the result of
in-breeding among all individuals of the separated
portion will eventually be different from that which
obtains in the other portion ; so that, after a number
of generations, the separated portion may become
a distinct species from the effect of isolation alone.
Even without the aid of isolation, any original dif-
ference of average characters may become, as it
were, magnified in successive generations, provided
that the divergence is not harmful to the individuals
.presenting it, and that it occurs in a sufficient pro-
portional number of individuals not to be immedi-
ately swamped by intercrossing. For, as Mr. Murphy
has pointed out, in accordance with Delboeufs law,
"if, in any species, a number of individuals, bearing
a ratio not infinitely small to the entire number of
births, are in every generation born with a particular
variation which is neither beneficial nor injurious,

* Divergent Evoluion through Cumulative Segregation^ Linn. Jouin.
Zoology, vol. XX. p. 215.

Characters as Adaptive and Specific, 225

and if it be not counteracted by reversion, then
the proportion of the new variety to the original
form will increase till it approaches indefinitely
near to equality ^." Now even Mr. Wallace himself
allows that this must be the case ; and thinks that in
these considerations we may find an explanation of
the existence of certain definite varieties, such as
the melanic form of the jaguar, the brindled or ring-
eyed guillemot, &c. But, on the other hand, he
thinks that such varieties must always be unstable,
and continually produced in varying proportions
from the parent forms. We need not, however,
wait to dispute this arbitrary assumption, because
we can see that it fails, even as an assumption, in
all cases where tlie superadded influence of isolation
is concerned. Here there is nothing to intercept
the original tendency to divergent evolution, which
arises directly out of the initially different average
of qualities presented by the isolated section of the
species, as compared with the rest of that species ^.

* Habit and Intelligence, p. 241.

* Allusion may here again be made to the case of the niata cattle.
For here is a case where a very extreme variety is certainly not unstable,
nor produced in varyin^^ proportions from the parent form. Moreover,
as we have seen in the preceding chapter, this almost monstrous
variety most probably originated as an individual sport— being after-
wards maintained and multiplied for a time by artificial selection. Now,
whether or not this was the case, we can very well see that it may have
been. Hence it will serve to illustrate another possibility touching the
origin and maintenance of useless specific characters. For what is
to prevent an individual congenital variation of any kind (provided it
be not harmful) from perpetuating itself as a " varietal," and eventually,
should offspring become sufficiently numerous, a *' specific character " ?
There is nothing to prevent this, save panmixia, or the presence of free
intercrossing. But, as we shall see in the next division of this treatise,
there are in nature many forms of isolation. Hence, as often as a small
number of individuals may have experienced isolation in any of its forms,

II. Q

226 Darwifij and after Darwin,

As we shall have to consider the important principle
of isolation more fully on a subsequent occasion,
I need not deal with it in the present connexion,
further than to remark that in this principle we have
what appears to me a full and adequate condition to
the rise and continuance of specific characters which
need not necessarily be adaptive characters. And, when
we come to consider the facts of isolation more closely,
we shall find superabundant evidence of this having
actually been the case.

V. Laws of Growth.

Under this general term Darwin included the opera-
tion of all unknown causes internal to organisms
leading to modifications of form or structure — such
modifications, therefore, appearing to arise, as he
says " spontaneously," or without reference to utility.
That he attributed no small importance to the opera-
opportunity for perpetuation will have been given to any congenital
variations which may happen to arise. Should any of these be pronounced
variations, it would afterwards be ranked as a specific character.
I do not myself think that this is the way in which indifferent specific
characters usually originate. On the contrary, I believe that their
origin is most frequently due to the influence of isolation on the average
characters of the whole population, as briefly stated in the text. But
here it seems worth while to notice this possibility of their occa-
sionally arising as merely individual variations, afterwards perpetuated
by any of the numerous isolating conditions which occur in nature.
For, if this can be the case with a varietal form so extreme as to border
on the monstrous, much more can it be so with such minute differences
as frequently go to constitute specific distinctions. It is the business of
species-makers to search out such distinctions, no matter how trivial,
and to record them as " specific characters." Consequently, wherever
in nature a congenital variation happens to arise, and to be perpetuated
by the force of heredity alone under any of the numerous forms of isola-
tion which occur in nature, there will be a case analogous to that of the
niata cattle.

Characters as Adaptive and Specific. 227

tion of these principles is evident from the last
edition of the Origin of Species. But as these " laws
of growth " refer to causes confessedly unknown,
I will not occupy space by discussing this division
of our subject — further than to observe that, as we
shall subsequently see, many of the facts which
fall under it are so irreconcilably adverse to the
Wallacean doctrine of specific characters as univer-
sally adaptive, that in the face of them Mr. Wallace
himself appears at times to abandon his doctrine
in toto.

Q «

CHAPTER IX.

Characters as Adaptive and Specific
[continued).

It must have appeared strange that hitherto I
should have failed to distinguish between " true
species" and merely "climatic varieties." But it
will conduce to clearness of discussion if we con-
sider our subject point by point. Therefore, having
now given a fair statement of the facts of climatic
variation, I propose to deal with their theoretical
implications — especially as regards the distinction
which naturalists are in the habit of drawing
between them and so-called true species.

First of all, then, what is this distinction ? Take,
for example, the case of the Porto Santo rabbits.
To almost every naturalist who reads what has been
said touching these animals, it will have appeared
that the connexion in which they are adduced is
wholly irrelevant to the question in debate. For,
it will be said that the very fact of the seemingly
specific differentiation of these animals having proved
to be illusory when some of them were restored to
their ancestral conditions, is proof that their peculiar
characters are not specific characters ; but only what
Mr. Wallace would term " individual characters/' or

Characters as Adaptive and Specific, 229

variations that are not inherited. And the same
remark applies to all the other cases which have been
adduced to show the generality and extent of climatic
variation, both in other animals and also in plants.
Why, then, it will be asked, commit the absurdity of
adducing such cases in the present discussion ? Is it
not self-evident that however general, or however
considerable, such merely individual, or non-heritable,
variations may be, they cannot possibly have ever had
anything to do with the origin of species ? Therefore, is
it not simply preposterous to so much as mention
them in relation to the question touching the utility
of specific characters?

Well, whether or not it is absurd and preposterous
to consider climatic variations in connexion with the
origin of species, will depend, and depend exclusively,
on what it is that we are to understand by a species.
Hitherto I have assumed, for the sake of argument,
that we all know what is meant by a species. But
the time has now come for showing that such is far
from being the case. And as it would be clearly
absurd and preposterous to conclude anything with
regard to specific characters before agreeing upon
what we mean by a character as specific, I will
begin by giving all the logically possible definitions
of a species.

I . A group of individuals descended by zvay of natural
generation from an originally and specially created type.

This definition may be taken as virtually obsolete.

a. A group of individuals which^ while fully fertile
inter se, are sterile with all other individuals — or^ at
any rate, do not generate fully fertile hybrids.

This purely physiological definition is not nowadays

230 Darwin, and after Darwin,

entertained by any naturalist. Even though the
physiological distinction be allowed to count for
something in otherwise doubtful cases, no systematist
would constitute a species on such grounds alone.
Therefore we need not concern ourselves with this
definition, further than to observe that it is often
taken as more or less supplementary to each of the
following definitions.

3. A group of individuals which, however many
characters they share with other individuals^ agree in
presenting one or more characters of a peculiar kind,
with some certain degree of distinctness.

In this we have the definition which is practically
followed by all naturalists at the present time. But,
as we shall presently see more fully, it is an extremely
lax definition. For it is impossible to determine, by
any fixed and general rule, what degree of distinctness
on the part of peculiar characters is to be taken as
a uniform standard of specific separation. So long
as naturalists believed in special creation, they could
feel that by following this definition (3) they were
at any rate doing their best to tabulate very real
distinctions in nature — viz. between types as originally
produced by a supernatural cause, and as subsequently
more or less modified (i. e. within the limits imposed
by the test of cross-fertility) by natural causes. But
evolutionists are unable to hold any belief in such
real distinctions, being confessedly aware that all
distinctions between species and varieties are purely
artificial. So to speak, they well know that it is
they themselves who create species, by determining
round what degrees of differentiation their diagnostic
boundaries shall be drawn. And, seeing that these

Characters as Adaptive and Specific. 231

degrees of differentiation so frequently shade into
one another by indistinguishable stages (or, rather,
that they always do so, unless intermediate varieties
have perished), modern naturalists are vi^ell avi^ake to
the impossibility of securing any approach to a uniform
standard of specific distinction. On this account
many of them feel a pressing need for some firmer
definition of a species than this one — which, in
point of fact, scarcely deserves to be regarded as
a definition at all, seeing that it does not formu-
late any definite criterion of specific distinctness,
but leaves every man to follow his own standards
of discrimination. Now, as far as I can see,
there are only two definitions of a species which
will yield to evolutionists the steady and uniform
criterion required. These two definitions are as
follows.

4. A group of individuals which, however many
characters they share with other individuals, agree in
presenting one or more characters of a peculiar and
hereditary kind, ivith some certain degree of dis-
tinctness.

It will be observed that this definition is exactly
the same as the last one, save in the addition of the
words "and hereditary." But, it is needless to say,
the addition of these words is of the highest im-
portance, inasmuch as it supplies exactly that objective
and rigid criterion of specific distinctness which the
preceding definition lacks. It immediately gets rid
of the otherwise hopeless wrangling over species as
*' good " and " bad." or " true " and " climatic," of
which (as we have seen) Kerner's essay is such
a remarkable outcome. Therefore evolutionists have

232 Darwifiy and after Darwin,

more and more grown to lay stress on the hereditary
character of such pecuh'arities as they select for
diagnostic features of specific distinctness. Indeed
it is not too much to say that, at the present time,
evolutionists in general recognize this character as,
theoretically, indispensable to the constitution of
a species. But it is likewise not too much to say
that, practically, no one of our systematic naturalists
has hitherto concerned himself with this matter.
At all events, I do not know of any who has ever
taken the trouble to ascertain by experiment, with
regard to any of the species which he has consti-
tuted, whether the peculiar characters on which his
diagnoses have been founded are, or are not, heredi-
tary. Doubtless the labour of constituting (or, still
more, of r^-constituting) species on such a basis of
experimental inquiry would be insuperable; while,
even if it could be accomplished, would prove unde-
sirable, on account of the * chaos it would produce
in our specific nomenclature. But, all the same, we
must remember that this nomenclature as we now
have it— and, therefore, the partitioning of species as
we have now made them — has no reference to the
criterion of heredity. Our system of distinguishing
between species and varieties is not based upon the
definition which we are now considering, but upon
that which we last considered — frequently coupled,
to some undefinable extent, with No. 2.

5. There is, however, yet another and closer defini-
tion, which may be suggested by the ultra- Darwinian
school, who maintain the doctrine of natural selection
as the only possible cause of the origin of species,
namely : —

I

Characters as Adaptive and Specific, 233

A group of individuals which y however many
characters they share with other individuals, agree
in presenting one or more characters of a peculiar,
hereditary, and adaptive kind, with some certain degree
of distinctness.

Of course this definition rests upon the dogma of
utility as a necessary attribute of characters qu&
specific — i. e. the dogma against which the whole
of the present discussion is directed. Therefore
all I need say with reference to it is, that at
any rate it cannot be adduced in any argument
where the validity of its basal dogma is in question.
For it would be a mere begging of this question to
argue that every species must present at least one
peculiar and adaptive character, because, according
to definition, unless an organic type does present at
least one such character, it is not a specific type.
Moreover, and quite apart from this, it is to be hoped
that naturalists as a body will never consent to base
their diagnostic work on what at best must always
be a highly speculative extension of the Darwinian
theory. While, lastly, if they were to do so with
any sort of consistency, the precise adaptation which
each peculiar character subserves, and which because
of this adaptation is constituted a character of specific
distinction, would have to be determined by actual
observation. For no criterion of specific distinction
could be more vague and mischievous than this one,
if it were to be applied on grounds of mere inference
that such and such a character, because seemingly
constant, must '* necessarily" be either useful, vestigial,
or correlated.

Such then, as far as T can see, are all the

234 Darwin^ and after Darwin.

definitions of a species that are logically possible^.
Which of them is chosen by those who maintain
the necessary usefulness of all specific characters ?
Observe, it is for those who maintain this doctrine
to choose their definition : it is not for me to do so.
My contention is, that the term does not admit of
any definition sufficiently close and constant to serve
as a basis for the doctrine in question — and this for
the simple reason that species-makers have never
agreed among themselves upon any criterion of specific
distinction. My opponents, on the other hand, are
clearly bound to take an opposite view, because,
unless they suppose that there is some such definition
of a species they would be self-convicted of the
absurdity of maintaining a great generalization on
a confessedly untenable basis. For example, a few
years ago I was allowed to raise a debate in the
Biological Section of the British Association on the
question to which the present chapters are devoted.
But the debate ended as I had anticipated that it
must end. No one of the naturalists present could
give even the vaguest definition of what was meant by

* It is almost needless to say that by a definition as " logical *'
is meant one which, while including all the differentiae of the thing
defined, excludes any qualities which that thing may share in common
with any other thing. But by definitions as " logically possible " I mean
the number of separate definitions which admit of being correctly given
of the same thing from different points of view. Thus, for instance, in
the present case, since the above has been in type the late M. Quatre-
fages' posthumous work on Darwin et ses Precurseurs Francois has
been published, and gives a long list of definitions of the term " species"
which from time to time have been enunciated by as many naturalists
of the highest standing as such (pp 1S6-187). But while none of
these twenty or more definitions is logical in the sense just defined,
they all present one or other of the differentiae given by those in
the text.

Characters as Adaptive and Specific, 235

a species — or, consequently, of a character as specific.
On this account the debate ended in as complete
a destruction as was possible of the doctrine that
all the distinctive characters of every species must
necessarily be useful vestigial, or correlated. For it
became unquestionable that the same generalization
admitted of being made, with the same degree of
effect, touching all the distinctive characters of every
"snark."

Probably, however, it will be thought unfair to have
thus sprung a difficult question of definition in oral
debate. Therefore I allude to this fiasco at the
British Association, merely for the purpose of em-
phasizing the necessity of agreeing upon some defini-
tion of a species, before we can conclude anything with
regard to the generalization of specific characters as
necessarily due to natural selection. But when a
naturalist has had full time to consider this funda-
mental matter of definition, and to decide on what
his own shall be, he cannot complain of unfairness on
the part of any one else who holds him to what he
thus says he means by a species. Now Mr. Wallace,
in his last work, has given a matured statement of
what it is that he means by a species. This, there-
fore, I will take as the avowed basis of his doctrine
touching the necessary origin and maintenance of all
specific characters by natural selection. His definition
is as follows : —

" An assemblage of individuals which have become somewhat
modified in structure, form, and constitution, so as to adapt them
to slightly different conditions of life ; which can be differen-
tiated from allied assemblages ; which reproduce their like ; which
usually breed together ; and, perhaps, when crossed with their

236 Darwin, and after Darwin,

near allies, always produce oflfspring which are more or less sterile
inter se ^."

From this definition the portion which I have
italicized must be omitted in the present discussion,
for the reasons already given while considering
definition No. 5. What remains is a combination of
Nos. 2 and 4. According to Mr. Wallace, therefore,
our criterion of a species is to be the heredity of
peculiar characters, combined, perhaps, with a more
or less exclusive fertility of the component individuals
inter se. This is the basis on which his generalization
of the utility of specific characters as necessary and
universal is reared. Here, then, we have something
definite to go upon, at all events as far as Mr. Wallace
is concerned. Let us see how far such a basis of
definition is competent to sustain his generalization.

First of all it must be remarked that, as species
have actually been constituted by systematists, the
test of exclusive fertility does not apply. For my
own part I think this is to be regretted, because
I believe that such is the only natural — and there-
fore the only firm — basis on which specific dis-
tinctions can be reared. But, as previously observed,
this is not the view which has been taken by our
species-makers. At most they regard the physio-
logical criterion as but lending some additional weight
to their judgement upon morphological features, in
cases where it is doubtful whether the latter alone
are of sufficient distinctness to justify a recognition
of specific value. Or, conversely, if the morphological
features are clearly sufficient to justify such a recog-
nition, yet if it happens to be known that there is

^ Darwinism, p. 167.

Characters as Adaptive and Specific. 237

full fertility between the form presenting them and
other forms which do not, then the latter fact will
usually prevent naturalists from constituting the well
differentiated form a species on grounds of its morpho-
logical features alone — as, for instance, in the case of
our domesticated varieties. In short, the physiological
criterion has not been employed with sufficient close-
ness to admit of its being now comprised within any
practical definition of the term " species " — if by this
term we are to understand, not what any one may
think species ought to be, but what species actually
are, as they have been constituted for us by their
makers.

From all this it follows that the definition of the
term " species " on which Mr. Wallace relies for his
deduction with respect to specific characters, is the
definition No. 4. In other words, omitting his petitio
prmcipii and his allusion to the test of fertility, the
great criterion in his view is the criterion of Heredity.
And in this all other evolutionists, of whatever school,
will doubtless agree with him. They will recognize
that it is really the distinguishing test between
" climatic varieties " and " true species," so that how-
ever widely or however constantly the former may
diverge from one another in regard to their peculiar
characters, they are not to be classed among the
latter unless their peculiar characters are likewise
hereditary characters.

Now, if we are all agreed so far, the only question
that remains is whether or not this criterion of
Heredity is capable of supplying a basis for the
generalization, that all characters which have been
ranked as of specific value must necessarily be

238 Darwin^ and after Darwin,

regarded as presenting also an adaptive, or life-
serving, value? I will now endeavour to show that
there are certain very good reasons for answering
this question in the negative.

(A.)

In the first place, even if the modifications induced
by the direct action of a changed environment are
not hereditary, who is to know that they are not?
Assuredly not the botanist or zoologist who in
a particular area finds what he is fully entitled to
regard as a well-marked specific type. Only by
experiments in transposition could it be proved
that the modifications have been produced by local
conditions; and although the researches of many
experimentalists have shown how considerable and
how constant such modifications may be, where is the
systematic botanist who would ever think of trans-
planting an apparently new species from one distant
area to another before he concludes that it is a new
species? Or where is the systematic zoologist who
would take the trouble to transport what appears
to be an obviously endemic species of animal from
one country to another before venturing to give it
a new specific name? No doubt, both in the case
of plants and animals, it is tacitly assumed that
constant differences, if sufficient in amount to be re-
garded as specific differences are hereditary ; but there
is not one case in a hundred where the validity of this
assumption has ever been tested by experiments
in transposition. Therefore naturalists are apt to
regard it as remarkable when the few experiments
which- have been made in this direction are found

(

Characters as Adaptive and Specific. 239

to negative their assumption — for example, that
a diagnostic character in species of the genus Hiera-
tium is found by transplantation not to be hereditary,
or that the several named species of British trout
are similarly proved to be all " local varieties " of one
another. But, in point of fact, there ought to be
nothing to surprise us in such results — unless, indeed,
it is the unwarrantable nature of the assumption that
any given differences of size, form, colour, &c., which
naturalists may have regarded as of specific value,
are, on this account, hereditary. Indeed, so sur-
prising is this assumption in the face of what we
know touching both the extent and the constancy
of climatic variation, that it seems to me such a
naturalist as Kerner, who never considers the
criterion of heredity at all, is less assailable than those
who profess to constitute this their chief criterion
of specific distinction. For it is certain that whatever
their professions may have nowadays become, sys-
tematic naturalists have never been in the habit
of really following this criterion. In theory they have
of late years attached more and more weight to
definition No. 4 ; but in practice they have always
adopted definition No. 3. The consequence is, that
in literally numberless cases (particularly in the
vegetable kingdom) "specific characters" are assumed
to be hereditary characters merely because systematic
naturalists have bestowed a specific name on the
form which presents them. Nor is this all. For,
conversely, even when it is known that constant mor-
phological characters are unquestionably hereditary
characters, if they happen to present but small
degrees of divergence from those of allied formS, then

240 Darvoin^ and after Darwin,

the form which presents them is not ranked as a
species, but as a constant variety. In o.ther words,
when definitions 3 and 4 are found to clash, it is not
4, but 3, that is followed. In short, even up to the
present time, systematic naturalists play fast and
loose with the criterion of Heredity to such an
extent, that, as above observed, it has been rendered
well nigh worthless in fact, whatever may be thought
of it in theory.

Now, unless all this can be denied, what is the
use of representing that a species is distinguished
from a variety — "climatic" or otherwise — by the
fact that its constituent individuals ''reproduce their
like"? We are not here engaged on any abstract
question of what might have been the best principles
of specific distinction for naturalists to have adopted.
We are engaged on the practical question of the
principles which they actually have adopted. And
of these principles the reproduction of like by like,
under all circumstances of environment, has been
virtually ignored.

(B.)

In the second place, supposing that the criterion
of Heredity had been as universally and as rigidly
employed by our systematists in their work of con-
structing species as it has been but occasionally and
loosely employed, could it be said that even then a basis
would have been furnished for the doctrine that all spe-
cific characters must necessarily be useful characters?
Obviously not, and for the following reasons.

It is admitted that climatic characters are not
necessarily — or even generally — useful characters.

Charade s as Adaptive and Specific. 241

Consequently, if there be any reason for believing
that climatic characters may become in time here-
ditary characters, the doctrine in question would
collapse, even supposing that all specific types were
to be re-constituted on a basis of experimental
inquiry, for the purpose of ascertaining which of
them conform to the test of Heredity. Now there
are very good reasons for believing that climatic
characters not unfrequently do become hereditary
characters ; and it was mainly in view of those
reasons that I deemed it worth while to devote so
much space in the preceding chapter to the facts of
climatic variation. I will now state the reasons in
question under two different lines of argument.

We are not as yet entitled to conclude definitely
against the possible inheritance of acquired char-
acters. Consequently, we are not as yet entitled
to assume that climatic characters — i. e. characters
acquired by converse with a new environment, con-
tinued, say, since the last glacial period — can never
have become congenital characters. But, if they ever
have become congenital characters, they will have
become, at all events as a general rule, congenital
characters that are usek'^ss ; for it is conceded that,
qud climatic characters, they have not been due to
natural selection.

Doubtless the followers of Weismann will repudiate
this line of argument, if not as entirely worthless,
at all events as too questionable to be of much
practical worth. But even to the followers of Weis-
mann it may be pointed out, that the Wallacean
doctrine of the origin of all specific characters by
means of natural selection was propounded many years

II. R

242 Darwin^ and after Darwin.

before either Galton or Weismann had questioned
the transmission of acquired characters. However.
I allow that this line of argument has now become
— for the time being at all events — a dubious line, and
will therefore at once pass on to the second line,
which is not open to doubt from any quarter.

Whether or not we accept Weismann's views, it
will here be convenient to employ his terminology,
since this will serve to convey the somewhat im-
portant distinctions which it is now my object to
express.

In the foregoing paragraphs, under heading (A), we
have seen that there must be " literally numberless
forms" which have been ranked as true species,
whose diagnostic characters are nevertheless not
congenital. In the case of plants especially, we know
that there must be large numbers of named species
which do not conform to the criterion of Heredity,
although we do not know which species they are.
For present purposes, however, it is enough for us
to know that there are many such named species,
where some change of environment has acted directly
and similarly on all the individual " somas " exposed
to it, without affecting their "germ-plasms," or the
material bases of their hereditary qualities. For named
species of this kind we may employ the term somato-
genetic species.

But now, if there are any cases where a change of
environment does act on the germ-plasms exposed to
it, the result would be what we may call bias to-
genetic species — i.e. species which conform to the
criterion of Heredity, and would therefore be ranked
by all naturalists as "true species." It would not

Characters as Adaptive and Specific, 243

signify in such a case whether the changed con-
ditions of life first affected the soma, and then, through
changed nutrition, the germ-plasm ; or whether
from the first it directly affected the germ -plasm itself.
For in either case the result would be a " species/'
which would continue to reproduce its peculiar
features by heredity.

Now, the supposition that changed conditions of life
may thus affect the congenital endowments of germ-
plasm is not a gratuitous one. The sundry facts
already given in previous chapters are enough to
show that the origin of a blastogerietic species by the
direct action on germ -plasm of changed conditions
of life is, at all events, a possibility. And a little
further thought is enough to show that this possibility
becomes a probability — if not a virtual certainty.
Even Weismann — notwithstanding his desire to main-
tain, as far as he possibly can, the *' stability" of
germ-plasm — is obliged to allow that external con-
ditions acting on the organism may in some cases
modify the hereditary qualities of its germ-plasm, and
so, as he says, " determine the phyletic development
of its descendants." Again, we have seen that he is
compelled to interpret the results of his own experi-
ments on the climatic varieties of certain butterflies
by saying, " I cannot explain the facts otherwise than
by supposing the passive acquisition of characters
produced by direct influences of climate"; by which
he means that in this case the influence of climate
acts directly on the hereditary qualities of germ-
plasm. Lastly, and more generally, he says : —

" But although I hold it improbable that individual variability
can depend on a direct action of external influences upon the

R 2

244 Darwin J and after Darwin.

germ-cells and their contained germ-plasm, because — as
tollows from sundry facts— the molecular structure of the
germ-plasm must be very difficult to change, yet it is by no
means to be implied that this structure may not possibly be
altered by influences of the same kind continuing for a very
long time. Thus it seems to me the possibility is not to be
rejected, that influences continued for a long time, that is,
for generations, such as temperature, kind of nourishment,
&c., which may affect the germ-cells as well as any other
part of the organism, may produce a change in the constitu-
tion of the germ-plasm. But such influences would not then
produce individual variation, but would necessarily modify in
the same way all the individuals of a species living in a certain
district. It is possible, though it cannot be proved, that
many climatic varieties have arisen in this manner."

So far, then, we have testimony to this point, as it
were, from a reluctant witness. But if we Have no
theory involving the " stability of germ-plasm " to
maintain, we can scarcely fail to see how susceptible
the germ-plasm is likely to prove to changed con-
ditions of life. For we know how eminently sus-
ceptible it is in this respect when gauged by the
practical test of fertility ; and as this is but an expres-
sion of its extraordinarily complex character, it would
indeed be surprising if it were to enjoy any immunity
against modification by changed conditions of life.
We have seen in the foregoing chapter how fre-
quently and how considerably somatogenetic changes
are thus caused, so as to produce '■ somatogenetic
species" — or, where we happen to know that the
changes are not hereditary, *' climatic varieties.'* But
the constitution of germ-plasm is much more complex
than that of any of the structures which are developed
therefrom. Consequently, the only wonder is that
hitherto experimentalists have not been more successful

Characters as Adaptive and Specific. 245

in producing " blastogenetic species" by artificial
changes of environment. Or, as Ray Lankester has
well stated this consideration, '* It is not difficult to
suggest possible ways in which the changed con-
ditions, shown to be important by Darwin, could act
through the parental body upon the nuclear matter
of the egg-cell and sperm-cell, with its immensely
complex and therefore unstable constitution. . . . The
wonder is, not that [blastogenetic] variation occurs,
but that it is not excessive and monstrous in every
product of fertilization ^."

If to this it should be objected that, as a matter
of fact, experimentalists have not been nearly so
successful in producing congenital modifications of
type by changed conditions of life as they have been
in thus producing merely somatic modifications ; or if it
should be further objected that we have no evidence
at all in nature of a "blastogenetic species" having
been formed by means of climatic influences alone, —
if these objections were to be raised, they would admit
of the following answer.

With regard to experiments, so few have thus far
been made upon the subject, that objections founded
on their negative results do not carry much weight —
especially when we remember that these results have
not been uniformly negative, but sometimes positive,
as shown in Chapter VI. With regard to plants and
animals in a state of nature, the objection is wholly
futile, for the simple reason that in as many cases as
changed conditions of life may have caused an here-
ditary change of specific type, there is now no means

^ A'a/wr^, Dec. la, 1889, P- 129.

246 DarwiUy and aftei Darwin,

of obtaining " evidence " ..pen the subject. But we
are not on this account entitled to conclude against
the probability of such changes of specific type
having been more or less frequently thus produced.
And still less can we be on this account entitled to
conclude against the possibility of such a change
having ever occurred in any single instance. Yet
this is what must be concluded by any one who
maintains that the origin of all species— and, a for-
tiori, of all specific characters — must necessarily have
been due to natural selection.

Now, if all this be admitted — and I do not see how
it can be reasonably questioned — consider how impor-
tant its bearing becomes on the issue before us. If
germ-plasm (using this term for whatever it is that
constitutes the material basis of heredity) is ever
capable of having its congenital endowments altered
by the direct action of external conditions, the result-
ing change of hereditary characters, whatever else
it may be, need not be an adaptive change. Indeed,
according to Weismann's theory of germ-plasm, the
chances must be infinitely against the change being
an adaptive one. On the theory of pangenesis — that
is to say, on the so-called Lamarckian principles —
there would be much more reason for entertaining the
possibly adaptive character of hereditary change due
to the direct action of the environment. Therefore
we arrive at this curious result. The more that we are
disposed to accept Weismann's theory of heredity, and
with it the corollary that natural selection is the sole
cause of adaptive modification in species the less are
we entitled to assume that all specific characters
must necessarily be adaptive. Seeing that in nature

Characters as Adaptive and Specific. 2^^

there are presumably many cases like those of Hoff-
mann's plants, Weismann's butterflies, &c., where the
hereditary qualities of germ-plasm have (on his hypo-
thesis) been modified by changed conditions of life,
we are bound to believe that, in all cases where such
changes do not happen to be actively deleterious,
they will persist. And inasmuch as characters which
are only of '• specific " value must be the characters
most easily — and therefore most frequently — induced
by any slight changes in the constitution of germ-
plasm, while, for the same reason (namely, that of
their trivial nature) they are least likely to prove
injurious, it follows that the less we believe in the
functionally-produced adaptations of Lamarck, the
more ought we to resist the assumption that all
specific characters must necessarily be adaptive
characters.

Upon the whole, then, and with regard to the
direct action of external conditions, I conclude— not
only from general considerations., but also from special
facts or instances quite sufficient for the purpose —
that these must certainly give rise to immense num-
bers of somatogenetic species on the one hand, and
probably to considerable numbers of blastogenetic
species on the other ; that in neither case is there any
reason for supposing the distinctively " specific char-
acters " to be other than " neutral " or " indifferent";
while there are the best of reasons for concluding the
contrary. So that, under this division of our subject
alone (B), there appears to be ample justification
for the statement that " a large proportional number
of specific characters " are in reality, a« they are in

248 Darwin^ and after Darwin,

appearance, destitute of significance from a utilitarian
point of view.

(C.)

Thus far in the present chapter we have been
dealing exclusively with the case of " climatic varia-
tion," or change of specific type due to changes in
the external conditions of life. But it will be remem-
bered that, in the preceding chapter, allusion was
likewise made to changes of specific type due to
internal causes, or to what Darwin has called " the
nature of the organism." Under this division of
our subject I mentioned especially Sexual Selection,
which is supposed to arise in the aesthetic taste
of animals themselves ; Isolation, which is supposed
to originate new types by allowing the average
characters of an isolated section of an old type to
develop a new history of varietal change, as we shall
see more fully in the ensuing part of this treatise ;
and the Laws of Growth, which is a general term for
the operation of unknown causes of change incidental
to the living processes of organisms which present the
change.

Now, under none of these divisions of our subject
can there be any question touching the criterion of
Heredity. For if new species — or even single specific
characters of new species — are ever produced by any
of these causes, they must certainly all " reproduce
their like." Therefore the only question which can
here obtain is as to whether or not such causes ever do
originate new species, or even so much as new specific
characters. Mr. Wallace, though not always consis-
tently, answers this question in the negative ; but the

Characters as Adaptive and Specific. 249

great majority of naturalists follow Darwin by answering
it in the affirmative. And this is enough to show the
only point which we need at present concern ourselves
with showing — viz. that the question is, at the least,
an open one. For as long as this question is an open
one among believers in the theory of natural selection,
it must clearly be an unwarrantable deduction from
that theory, that all species, and a fortiori all specific
characters, are necessarily due to natural selection.
The deduction cannot be legitimately drawn until
the possibility of any other cause of specific modifica-
tion has been excluded. But the bare fact of the
question as just stated being still and at the least an
open question, is enough to prove that this possibility
has not been excluded. Therefore the deduction must
be, again on this ground alone (C), unwarrantable.

Such are my several reasons — and it is to be
observed that they are all independent reasons — foi
concluding that it makes no practical difference to
the present discussion whether or not we entertain
Heredity as a criterion of specific distinction. Seeing
that our species- makers have paid so little regard to
this criterion, it is neither absurd nor preposterous
to have adduced, in the preceding chapter, the facts
of climatic variation. On the contrary, as the defini-
tion of " species " which has been practically followed
by our species-makers in No. 3, and not No. 4, these
facts form part and parcel of our subject. It is per-
fectly certain that, in the vegetable kingdom at all
events, " a large proportional number " of specifically
diagnostic characters would be proved by experiment
to be '* somatogenetic " ; while there are numerous

250 Darwin, and after Darwin.

constant characters classed as varietal, although it is
well known that they are " blastogenetic.'* Moreover,
we can scarcely doubt that many specific characters
which are also hereditary characters owe their exist-
ence, not to natural selection, but to the direct action
of external causes on the hereditary structure of
" germ-plasm " ; while, even apart from this con-
sideration, there are at least three distinct and highly
general principles of specific change, which are ac-
cepted by the great majority of Darwinists, and the
only common peculiarity of which is that they pro-
duce hereditary changes of specific types without any
reference to the principle of utility.

CHAPTER X.

Characters as Adaptive and Specific
{concluded).

Our subject is not yet exhausted. For it remains
to observe the consequences which arise from the
dogma of utility as the only raison d'itre of species,
or of specific characters, when this dogma is applied
in practice by its own promoters.

Any definition of " species " — excepting Nos. I, %,
and 5, which may here be disregarded — must needs
contain some such phrase as the one with which Nos. 3
and 4 conclude. This is, that peculiar characters, in
order to be recognized as of specific value, must
present neither more nor less than "some certain
degree of distinctness." If they present more than
this degree of distinctness, the form, or forms, in
question must be ranked as generic ; while if they
present less than this degree of distinctness, they
must be regarded as varietal — and this even if
they are known to be mutually sterile. What,
then, is this certain degree of distinctness.? What
are its upper and lower limits? This question is
one that cannot be answered. From the very
nature of the case it is impossible to find a

252 Darwin^ and after Darwin.

uniform standard of distinction whereby to draw
our boundary lines between varieties and species
on the one hand, or between species and genera on
the other. One or two quotations will be sufficient
to satisfy the general reader upon this point.

Mr. Wallace himself alludes to "the great diffi-
culty that is felt by botanists in determining the
limits of species in many large genera," and gives
as examples well-known instances where systematic
botanists of the highest eminence differ hopelessly
in their respective estimates of "specific characters."
Thus : —

" Mr. Baker includes under a single species, Rosa canina,
no less than twenty-eight named varieties distinguished by
more or less constant characters, and often confined to special
localities, and to these are referred about seventy of the
species of British and continental botanists. Of the genus
Rubus or bramble, five British species are given in Bentham's
Handbook of British Flora^ while in the fifth edition of
Babington's Manual of British Botany, published about the
same time, no less than forty-five species are described. Of
willows (Salix) the same two works enumerate fifteen and
thirty-one species respectively. The hawkweeds (Hieracium)
are equally puzzling, for while Mr. Bentham admits only seven
British species, Professor Babington describes no less than
seventy-two, besides several named varieties ^"

Mr. Wallace goes on to quote further instances,
such as that of Draba verna, which Jordan has
found to present, in the south of France alone, no less
than fifty-two permanent varieties, which all "come
true from seed, and thus present all the character-
istics of a true species*'; so that, "as the plant is

' Darwinism, p. 77.

characters as Adaptive and Specific. 253

very common almost all over Europe, and ranges
from North America to the Himalayas, the number
of similar forms over this wide area would probably
have to be reckoned by hundreds, if not by thou-
sands ^.'*

One or two further quotations may be given to
the same general effect, selected from the writings of
specialists in their several departments.

" There is nothing that divides systematists more than what
constitutes a genus. Species that resemble each other more than
other species, is perhaps the best definition that can be given.
This is obviously an uncertain test, much depending on
individual judgement and experience ; but that, in the evolu-
tion of forms, such difficulties should arise in the limitation
of genera and species was inevitable. What is a generic
character in one may be only a specific character in another.
As an illustration of the uncertain importance of characters,
I may mention the weevil genus Centrinus, in which the
leading characters in the classification of the family to w^aich
it belongs are so mixed that systematists have been content
to keep the species together in a group that cannot be defined.
. . . No advantage or disadvantage is attached, apparently,
to any of the characters. There are about 200 species, all
American.

^ The venation of the wings of insects is another example of
modifications without serving any special purpose. There is
no vein in certain Thripidae, and only a rudiment or a single
vein in Chalcididae. There are thousands of variations more
or less marked, some of the same type with comparatively
trivial variation, others presenting distinct types, even in the
same family, such genera, for example, as Polyneura^ Tetii-
getra, Huechys^ &c. in the Cicadidae.

Individual differences have often been regarded as distinctive

of species ; varieties also are very deceptive, and races come

very near to species. A South-American beetle, Arescus

histriOf has varieties of yellow, red, and black, or these colours

' Darwinism, p. 77.

254 DarwiUy and after Darzvin,

variously intermixed, and, what is very unusual, longitudinal
stripes in some and transverse bars in others, and all taken
in the same locality. Mr. A. G. Butler, of the British Museum,
is of opinion that 'what is generally understood by the term
species (that is to say, a well-defined, distinct, and constant type,
having no near allies) is non-existent in the Lepidoptera, and
that the nearest approach to it in this order is a constant, though
but slightly differing, rare or local form— that genera, in fact, con-
sist wholly of a gradational series of such forms (Ann. Mag. Nat.
Hist. 5, xix. io3)V "

So much as regards entomology, and still living
forms. In illustration of the same principles in
connexion with palaeontological series, I may quote
Wiirtenberger, who says : —

"With respect to these fossil forms [i.e. multitudinous forms
of fossil Ammonites], it is quite immaterial whether a very
short or a somewhat longer part of any branch be dignified with
a separate name, and regarded as a species. The prickly
Ammonites, classed under the designation of Armata, are so
intimately connected that it becomes impossible to separate the
accepted species sharply from one another. The same remark
applies to the group of which the manifold forms are distin-
guished by their ribbed shells, and are called Planulata '^."

I had here supplied a number of similar quotations
from writers in various other departments of systematic
work, but afterwards struck them out as superfluous.
For it is not to be anticipated that any competent
naturalist will nowadays dispute that the terms
"variety," "species," and "genus" stand for merely
conventional divisions, and that whether a given form
shall be ranked under one or the other of them is

* Pascoe, The Darwinian Theory of the Origin of Species, 1891,
pp. 3i-33» and 46.
" Neuer Beitrag zum geologischen Beweis der Darwin schen Theorie,

1873.

Characters as Adaptive and Specific. 255

often no more than a matter of individual taste.
From the nature of the case there can be no objective,
and therefore no common, standards of delimitation.
This is true even as regards any one given depart-
ment of systematic work ; but when we compare the
standards of delimitation which prevail in one depart-
ment with those which prevail in another, it becomes
evident that there is not so much as any attempt at
agreeing upon a common measure of specific dis-
tinction.

But what, it may well be asked, is the use of thus
insisting upon well-known facts, which nobody will
dispute? Well, in the first place, we have already
seen, in the last chapter, that it is incumbent on those
who maintain that all species, or even all specific
characters, must be due to natural selection, to tell us
what they mean by a species, or by characters as
specific. If I am told to believe that the definite
quality A is a necessary attribute of B, and yet that
B is " not a distinct entity," but an undefinable ab-
straction, I can only marvel that any one should
expect me to be so simple. But, without recurring
to this point, the use of insisting on the facts above
stated is, in the second place, that otherwise I cannot
suppose any general reader could believe them in view
of what is to follow. For he cannot but feel that the
cost of believing them is to render inexplicable the
mental processes of those naturalists who, in the face of
such facts, have deduced the following conclusions.

The school of naturalists against which I am
contending maintains, as a generalization deduced
from the theory of natural selection, that all species,
or even all specific characters, must necessarily owe

256 Darwiriy and after Darwin.

their origin to the principle of utility. Yet this same
school does not maintain any such generalization,
either with regard to varietal characters on the one
hand, or to generic characters on the other. On the
contrary, Professor Huxley, Mr. Wallace, and all
other naturalists who agree with them in refusing to
entertain so much as the abstract possibility of any
cause other than natural selection having been pro-
ductive of species, fully accept the fact of other
causes having been largely concerned in the production
of varieties, genera, families, and all higher groups,
or of the characters severally distinctive of each.
Indeed, Mr. Wallace does not question what appears
to me the extravagant estimate of Professor Cope,
that the non-adaptive characters distinctive of those
higher groups are fully equal, in point of numbers, to
the adaptive. But, surely, if the theory of evolution
by natural selection is, as we all agree, a true theory
of the origin of species, it must likewise be a true
theory of the origin of genera ; and if it be supposed
essential to the integrity of the theory in its former
aspect that all specific characters should be held to
be useful, I fail to see how, in regard to its latter
aspect, we are so readily to surrender the necessary
usefulness of all generic characters. And exactly the
same remark applies to the case of constant "varieties,"
where again the doctrine of utility as universal is not
maintained. Yet, according to the general theory of
evolution, constant varieties are what Darwin termed
"incipient species," while species are what may be
termed " incipient genera." Therefore, if the doctrine
of utility as universal be conceded to fail in the case
of varieties on the one hand and of genera on the

Characters as Adaptive and Specific. 257

other, where is the consistency in maintaining that it
must "necessarily" hold as regards the intermediate
division, species? Truly the shade of Darwin may
exclaim, " Save me from my friends." And truly
against logic of this description a follower of Darwin
must fijid it difficult to argue. If one's opponents
were believers in special creation, and therefore stood
upon some definite ground while maintaining this
difference between species and all other taxonomic
divisions, there would at least be some issue to argue
about. But when on the one hand it is conceded
that species are merely arbitrary divisions, which
differ in no respect as to the process of their evolution
from either varieties or genera, while on the other
hand it is affirmed that there is thus so great a
difference in the result, all we can say is that our
opponents are entangling themselves in the meshes
of a sheer contradiction.

Or, otherwise stated, specific characters differ from
varietal characters in being, as a rule, more pronounced
and more constant : on this account advocates of
utility as universal apply the doctrine to species,
while they do not feel the '* necessity " of applying it
to varieties. But now, generic and all higher char-
acters are even more constant and more pronounced
than specific characters — not to say, in many cases,
more generally diffused over a larger number of
organisms usually occupying larger areas. There-
fore, a fortiori^ if for the reasons above stated evolu-
tionists regard it as a necessary deduction from th?
theory of natural selection that all specific char-
acters must be useful, much more ought it to be
a necessary deduction from this theory that all generic,

II. s

258 Darwin, and after Darwin.

and still more all higher, characters must be useful.
But, as we have seen, this is not maintained by our
opponents. On the contrary, they draw the sharpest
distinction between specific and all other characters in
this respect, freely conceding that both those below
and those above them need not — and very often do
not — present any utilitarian significance.

Although it appears to me that this doctrine is self-
contradictory, and on this ground alone might be
summarily dismissed, as it is now held, in one or
other of its forms by many naturalists, I will give it
a more detailed consideration in both its parts —
namely, first with respect to the distinction between
varieties and species, and next with respect to the
distinction between species and genera.

Until it can be shown that species are something
more than merely arbitrary divisions, due to the
disappearance of intermediate varietal links ; that in
some way or another they are "definite entities,"
which admit of being delineated by the application of
some uniform or general principles of definition ;
that, in short, species have only then been classified
as such when it has been shown that the origin of
each has been due to the operation of causes which
have not been concerned in the production of varieties ;
— until these things are shown, it clearly remains
a gratuitous dogma to maintain that forms which
have been called species differ from forms which have
been called varieties in the important respect, that
they (let alone each of all their distinctive characters)
must necessarily have been due to the principle of
utility Yet, as we have seen, even Mr. Wallace

Characters as Adaptive and Specific. 259

allows that a species is " not a distinct entity," but
" an assemblage of individuals which have become
somewhat modified in structure, form, and consti-
tution"; while estimates of the kinds and degrees
of modification which are to be taken as of specific
value are conceded to be undefinable, fluctuating, and
in not a few cases almost ludicrously divergent.

Perhaps one cannot more forcibly present the
rational value of this position than by noting the fol-
lowing consequences of it. Mr. Gulick writes me that
while studying the land-shellsof the Sandwich Islands,
and finding there a rich profusion of unique varieties,
in cases where the intermediate varieties were rare he
could himself have created a number of species by
simply throwing these intermediate varieties into his
fire. Now it follows from the dogma which we are
considering, that, by so doing, not only would he
have created new species, but at the same time
he would have proved them due to natural selection,
and endowed the diagnostic characters of each with
a " necessarily " adaptive meaning, which previously it
was not necessary that they should present. Before
his destruction of these intermediate varieties, he need
have felt himself under no obligation to assume that
any given character at either end of the series was
of utilitarian significance : but, after his destruction of
the intermediate forms, he could no longer entertain
any question upon the matter, under pain of being
denounced as a Darwinian heretic.

Now the application is self-evident. It is a general

fact, which admits of no denial, that the more our

knowledge of any flora or fauna increases, the greater

is the number of intermediate forms which are

S 2

26o Darwifty and after Darwin,

brought to light, either as still existing or as having
once existed. Consequently, the more that such
knowledge increases, the more does our catalogue of
'• species " diminish. As Kerner says, '■ bad species "
are always multiplying at the expense of "good
species " ; or, as Oscar Schmidt (following Hackel)
similarly remarks, if we could know as much about
the latter as we do about the former, '• all species,
without any exception, would become what species-
makers understand by ' bad species ' ^." Hence we
see that, just as Mr. Gulick could have created good
species by secretly destroying his intermediate
varieties, so has Nature produced her '' good species "
for the delectation of systematists. And just as Mr.
Gulick, by first hiding and afterwards revealing his
intermediate forms, could have made the self-same
characters in the first instance necessarily useful, but
ever afterwards presumably useless, so has Nature
caused the utility of diagnostic characters to vary
with our knowledge of her intermediate forms. It
belongs to the essence of our theory of descent, that
in all cases these intermediate forms must either be
now existing or have once existed ; and, therefore,
that the work of species- makers consists in nothing
more than marking out the lacunae in our knowledge
of them. Yet we are bound to believe that wherever
these lacunae in our knowledge occur, there occurs
also the objective necessity of causation as utilitarian
— a necessity, however, which vanishes so soon as
our advancing information supplies the intermediate
forms in question. It may indeed appear strange that

* The Doctrine of Descent and Darwinism, Eng. Trans, p. loa.

Characters as Adaptive and Specific, 261

the utility or non-utility of organic structures should
thus depend on the accidents of human knowledge;
but this is the Darwinian faith, and he who doubts the
dogma is to be anathema.

Turning next to the similar distinction which it
is sought to draw between species and genera, here
it will probably be urged, as I understand it to
be urged by Mr. Wallace, that generic characters
(and still more characters of families, orders, &c.) refer
back to so remote a state of things that utility
may have been present at their birth which has
disappeared in their maturity. In other words, it
is held that all generic characters were originally
specific characters ; that as such they were all origin-
ally of use ; but that, after having been rendered
stable by heredity, many of them may have ceased
to be of service to the descendants of those species
in which they originated, and whose extinction has
now made it impossible to divine what that service
may have been.

Now, in the first place, this is not the interpretation
adopted by Darwin. For instance, he expressly
contrasts such cases with those of vestigial or " rudi-
mentary" structures, pointing out that they differ
from vestigial structures in respect of their perma-
nence. One quotation will be sufficient to establish
the present point.

"A structure which has been developed through long-con-
tinued selection, when it ceases to be of service to a species,
generally becomes variable, as we see with rudimentary organs,
for it will no longer be regulated by this same power of
selection. But when, from the nature of the organism and
of the conditions, modifications have been induced which are

262 DarwiUy and after Darwin,

unimportant for the welfare of the species, they may be, and
apparently often have been, transmitted in nearly the same
state to numerous, otherwise modified, descendants^"

Here, and in the context, we have a sufficiently-
clear statement of Darwin's view — first, that unadap-
tive characters may arise in species as "fluctuating
variations, which sooner or later become constant
through the nature of the organism and of surround-
ing conditions, as well as through the intercrossing
of distinct individuals, but not through natural selec-
tion " ^ ; second, that such unadaptive characters may
then be transmitted in this their stable condition to
species-progeny, so as to become distinctive of genera,
families, &c. ; third, that, on account of such characters
not being afterwards liable to diverse adaptive
modifications in different branches of the species-
progeny, they are of more value as indicating lines
of pedigree than are characters which from the first
have been useful ; and, lastly, they are therefore now
empirically recognized by systematists as of most
value in guiding the work of classification. To me
it appears that this view is not only perfectly rational
in itself, but likewise fiilly compatible with the theory
of natural selection — which, as I have previously
shown, is primarily a theory of adaptive characters,
and therefore not necessarily a theory of all specific
characters. But to those who think otherwise, it
must appear— and does appear — that there is some-
thing wrong about such a view of the case — that
it was not consistent in the author of the Origin of
Species thus to refer non-adaptive generic characters
to a parentage of non-adaptive specific characters.

* Origin of Species ^ p. 175. " Ibid. p. 176 : italics mine

Characters as Adaptive and Specific. 263

Nevertheless, as a matter of fact, Darwin was perfectly
consistent in putting forth this view, because, unlike
Wallace, he was not under the sway of any antecedent
dogma erroneously deduced from the theory of
natural selection.

Next, without reference to Darwin's authority, let
us see for ourselves where the inconsistency really lies.
To allow that generic characters may be useless, while
denying that specific characters can ever be so (unless
correlated with others that are useful), involves an
appeal to the argument from ignorance touching
the ancestral habits, life-conditions, &c., of a parent
species now extinct. Well, even upon this assumption
of utility as obsolete, there remains to be explained the
"stability" of useless characters now distinctive of
genera, families, orders, and the rest. We know that
specific characters which have owed their origin to
utility and have afterwards ceased to present utility,
degenerate, become variable, inconstant, "rudimen-
tary," and finally disappear. Why, then, should these
things not happen with regard to useless generic
distinctions.? Still more, why should they not happen
with regard to family, ordinal, and class distinctions?
On the lines against which I am arguing it would
appear impossible that any answer to this question
can be suggested. For what explanation can be
given of the contrast thus presented between the
obsolescence of specific characters where previous
utility is demonstrable, and the permanence of
higher characters whose previous utility is assumed ?
As we have already seen, Mr. Wallace himself
employs this consideration of permanence and con-
stancy against the view that any cause other than

264 Darwin^ and after Darwin.

natural selection can have been concerned in the
origin and maintenance of specific characters. But
he does not seem to see that the consideration cuts
two ways — and much more forcibly against his
views than in favour of them. For while, as already
shown in the chapter before last, it is sufficiently
easy to dispose of the consideration as Wallace uses
it (by simply pointing out with Darwin that any
causes other than natural selection which may have
been concerned in the genesis of specific characters,
must, if equally uniform in their operation, equally
give rise to permanence and constancy in their results) ;
on the other hand, it becomes impossible to explain
the stability of useless generic characters, if, as
Wallace's use of the argument requires, natural selec-
tion is the only possible cause of stability. The
argument is one that cannot be played with fast
and loose Either utility is the sole condition to
the stability of any diagnostic character (in which
case it is not open to Mr. Wallace to assume that
all generic or higher characters which are now use-
less have owed their origin to a past utility) ; or
else utility is not the sole condition to stability
(in which case his use of the present argument in
relation to specific characters collapses). We have
seen, indeed, in the chapter before last, that his use
of the argument collapses anyhow, or quite irrespec-
tive of his inconsistent attitude towards generic
characters, with which we were not then concerned.
But the point now is that, as a mere matter of logic,
the argument from stability as Wallace applies it
to the case of specific characters, is incompatible
with his argument that useless generic characters

Characters as Adaptive and Specific. 265

may originally have been useful specific characters.
It can scarcely be questioned that the transmuta-
tion of a species into a genus must, as a rule, have
allowed time enough for a newly acquired — i.e.
peculiar specific-character — to show some signs of
undergoing degeneration, if, as supposed, the original
cause of its development and maintenance was with-
drawn when the parent species began to ramify into its
species-progeny. Yet, as Darwin says, " it is notorious
that specific characters are more variable than
generic^." So that, upon the whole, I do not see
how on grounds of general reasoning it is logically
possible to maintain Mr. Wallace's distinction between
specific and generic characters in respect of necessary
utility.

But now, and lastly, we shall reach the same
conclusion if, discarding all consideration of general
principles and formal reasoning, we fasten attention
upon certain particular cases, or concrete facts.
Thus, to select only two illustrations within the
limits of genera, it is a diagnostic feature of the
genus Equus that small warty callosities occur on
the legs. It is impossible to suggest any useful
function that is now discharged by these callo-
sities in any of the existing species of the genus.
If- it be assumed that they must have been of
some use to the species from which the genus
originally sprang, the assumption, it seems to me,
can only be saved by further assuming that in existing
species of the genus these callosities are in a vesti-
gial condition — i. e. that in the original or parent
species they performed some function which is now

* Origin of Species^ p. 12a.

266 Darwin, and after Darwin,

obsolete. But against these assumptions there lies
the following fact. The callosities in question are
not similarly distributed through all existing species
of the genus. The horse has them " upon all
his four legs, while other species have them only
upon two. Therefore, if all specific characters are
necessarily due to natural selection, it is manifest
that these callosities are not now vestigial : on the
contrary, they /«2/j/ still be— or, at best, have recently
been — of so much importance to all existing species
of the genus, that not only is it a matter of selection-
' value to all these species that they should possess
these callosities ; but it is even a matter of selection-
value to a horse that he should possess four of
them, while it is equally a matter of selection-value
to the ass that he should possess only two. Here,
it seems to me, we have once more the doctrine of
the necessary utility of specific characters reduced
to an absurdity ; while at the same time we display
the incoherency of the distinction between specific
characters and generic characters in respect of this
doctrine. For the distinction in such a case amounts
to saying that a generic character, if evenly distributed
among all the species, need not be an adaptive
character ; whereas, if any one of the species presents
it in a slightly different form, the character must
be, on this account, necessarily adaptive. In other
words, the uniformity with which a generic character
occurs among the species of the genus is taken to
remove that character from the necessarily useful
class while the absence of such uniformity is taken
as proof that the character must be placed within
the necessarily useful class. Which is surely no less

Characters as Adaptive and Specific. 267

a reductio ad absurdum with regard to the generic
character than the one just presented with regard to
its variants as specific characters. And, of course,
this twofold absurdity is presented in all cases where
a generic character is unequally distributed among
the constituent species of a genus.

Eut here is an illustration of another class of cases.
Mr. Tomes has shown that the molar teeth of the
Orang present an extraordinary and altogether super-
fluous amount of attachment in their sockets — the fangs

Fig. 4.— Lower Teeth of Orang (after Tomes).

being not only exceedingly long, and therefore deeply
buried in the jaw-bone, but also curving round one
another, so as still further to strengthen the whole ^
In the allied genera of anthropoid apes there is no
such abnormal amount of attachment. Now, the
question is, of what conceivable use can it ever
have been, either to the existing genus, or to its
parent species, that such an abnormal amount of
attachment should obtain? It certainly is not re-
quired to prevent dislocation of the teeth, seeing that
in all allied genera, and even in man himself, the

* A Manual of Dental Anatomy, p. 455.

268 Darwin^ and after Darwin.

amount of attachment is already so great that teeth
will break before they can be drawn by anything
short of a dentist's forceps. Therefore I conclude
that this peculiarity in the dentition of the genus
must have arisen in its parent species by way
of what Darwin calls a " fluctuating variation," with-
out utilitarian significance. And I adduce it in
the present connexion because the peculiarity is one
which is equally unamenable to a utilitarian ex-
planation, whether it happens to occur as a generic
or a specific character.

Numberless similar cases might be quoted ; but
probably enough has now been said to prove the
inconsistency of the distinction which our opponents
draw between specific and all higher characters
in respect of utility. In point of fact, a very
little thought is enough to show that no such
distinction admits of being drawn ; an^, therefore,
that any one who maintains the doctrine of utility
as universal in the case of specific characters, must
in consistency hold to the same doctrine in the case
of generic and all higher characters. And the fact
that our opponents are unable to do this becomes
a virtual confession on their part of the futility of
the generalization which they have propounded ^.

* It may be observed that this distinction was not propounded by
Mr. Wallace — nor, so far as I am aware, by anybody else — until he
joined issue with me on the subject of specific characters. Whether he
has always held this important distinction between specific and generic
characters, I know not ; but, as originally enunciated, his doctrine of
Utility as universal was subject to no such limitation : it was stated
unconditionally, as applying to all taxonomic divisions indifferently.
The words have already been quoted on page 180; and, if the reader
will turn to them, he may further observe that, prior lo our discussion,
Mr. Wallace made no allowance for the principle of correlation, which,

Characters as Adaptive and Specific. 269

On what then do Mr. Wallace and his followers
reiy for their great distinction between specific and
all other characters in respect of utility? This is
the final and fundamental question which I must
leave these naturalists themselves to answer ; for my
whole contention is, that it is unanswerable. But
although I am satisfied that they have nothing on
which to base their generalization, it seems worth
while to conclude by showing yet one further point.
And this is, that these naturalists themselves, as soon
as they quit merely abstract assertions and come to
deal with actual facts, contradict their own general-
ization. It is worth while to show this by means of
a few quotations, that we may perceive how impossible
it is for them to sustain their generalization in the
domain of fact.

As it is desirable to be brief, I will confine myself
to quoting from Mr. Wallace.

" Colour may be looked upon as a necessary result of the
highly complex chemical constitution of animal tissues and
fluids. The blood, the bile, the bones, the fat, and other
tissues have characteristic, and often brilliant colours, which
we cannot suppose to have been determined for any special
purpose as colours, since they are usually concealed. The
external organs and integuments, would, by the same general
laws, naturally give rise to a greater variety of colour^."

Surely comment is needless. Have the colour of
external organs and integuments nothing to do with

as we have seen, furnishes so convenient a loop-hole of escape in cases
where even the argument from our ignorance of possible utility appears
absurd. In his latest work, liowever, he is much less sweeping in
his statements. He limits his doctrine to the case of " sj)ecific charac-
ters " alone, and even with regard to them makes unlimited drafts upon
the principle of correlation.
' Parwinism, p. 297.

270 Darwin^ and after Darwin.

the determining of specific distinctions by system-
atists? Or, may we not rather ask, are there any
other " characters " which have had more to do with
their delineation of animal species ? Therefore, if
" the external organs and integuments naturally give
rise to a greater variety of colours," for non-utilitarian
reasons, than is the case with internal organs and
tissues ; while even the latter present, for similarly
non-utilitarian reasons, such variety and intensity of
colours as they do ; must it not follow that, on the
ground of the " Laws of Growth " alone, Mr. Wallace
has conceded the entire case as regards " a large
proportional number of specific characters" being
non-adaptive — " spontaneous " in their occurrence,
and " meaningless " in their persistence ?
Once more : —

" The enormously lengthened plumes of the bird of paradise
and of the peacock, can, however, have no such use [i.e. for pur-
poses of defence], but must be rather injurious than beneficial
in the birds' ordinary life. The fact that they have been de-
veloped to so great an extent in a few species is an indication
of such perfect adaptation to the conditions of existence, such
complete success in the battle for life, that there is, in the
adult male at all events, a surplus of strength, vitality, and
growth-power, which is able to expend itself in this way without
injury. That such is the case is shown by the great abun-
dance of most of the species which possess these wonderful
superfluities of plumage. . . . Why, in allied species, the
development of accessory plumes has taken different forms, we
are unable to say, except that it may be due to that individual
variability which has served as a starting-point for so much
of what seems to us strange in form, or fantastic in colour,
both in the animal and vegetable world \"

Here, again, one need only ask, How can such state-

Darwinism, pp. 292-3.

Characters as Adaptive and Specific. 271

ments be reconciled with the great dogma, " which is
indeed a necessary deduction from the theory of
Natural Selection, namely, that none of the definite
facts of organic nature, no special organ, no character-
istic form or marking can exist, but which must now
be, or once have been, usefuV ? Can it be said that
the plumes of a bird of paradise present '^ no charac-
teristic form," or the tail of a peacock " no character-
istic marking " ? Can it be held that all the '• fantastic
colours/' which Darwin attributes to sexual selection,
and all the " strange forms " in the vegetable world
which present no conceivable reference to adaptation,
are to be ascribed to 'individual variability" without
reference to utility, while at the same time it is held,
" as a necessary deduction from the theory of Natural
Selection," that all specific characters must be ''• use-
ful " ? Or must we not conclude that we have here
a contradiction as direct as a contradiction can
well be ^ ?

Nor is it any more possible to reconcile these
contradictory statements by an indefinite extension
of the term " correlation," than we found it to be in
the cases previously quoted. It might indeed be
logically possible, howsoever biologically absurd, to
attribute the tail of a peacock — with all its elabora-
tion of structure and pattern of colour, with all the
drain that its large size and weight makes upon the
vital resources of the bird, with all the increased
danger to which it exposes the bird by rendering it
more conspicuous, more easy of capture, &c. — to
correlation with some useful character peculiar to

' Since the above was written both Mr. Gulick and Professor Lloyd
Morgan have independently noticed the contradiction.

272 Darwin^ and after Darwin.

peacocks. But to say that it is due to correlation
with general ''vitality/' is merely to discharge the
doctrine of correlation of any assignable meaning.
Vitality, or " perfect adaptation to the conditions of
existence," is obviously a prime condition to the
occurrence of a peacock's tail, as it is to the occur-
rence of a peacock itself; but this is quite a different
thing from saying that the specific characters which
are presented by a peacock's tail, although useless
in themselves, are correlated with some other and
useful specific characters of the same bird — as we saw
in a previous chapter with reference to secondary
sexual characters in general. Therefore, when Mr.
Wallace comes to the obvious question why it is that
even in " allied species," which must be in equally
" perfect adaptation to the conditions of existence,"
there are no such " wonderful superfluities of plumage,"
he falls back — as he previously fell back — on what-
ever unknown causes it may have been which pro-
duced the peacock's tail, when the primary condition
to their operation has been furnished by " complete
success in the battle for life."

I have quoted the above passages, not so much for
the sake of exposing fundamental inconsistencies on
the part of an adversary, as for the sake of observing
that they constitute a much truer exposition of
" Darwinism " than do the contradictory views ex-
pressed in some other parts of the work bearing that
title. For even if characters of so much size and elabo-
ration as the tail of a peacock, the plumes of a bird of
paradise &c., are admitted to be due to non-utilitarian
causes, much more must innumerable other characters
of incomparably less size and elaboration be mere

Characters as Adaptive and Specific. 273

"superfluities." Without being actually deleterious,
" a large proportional number of specific characters,"
whose utility is not apparent, vcwxst a fortiori have been
due to " individual variation," to ''' general laws which
determine the production" of such characters— or, in
short, to some causes other than natural selection.
And this, I say, is a doctrine much more in harmony
with " Darwinism " than is the contradictory doctrine
which I am endeavouring to resist.

But once again, and still more generally, after
saying of " the delicate tints of spring foliage, and the
intense hues of autumn," that "as colours they are
unadaptive, and appear to have no more relation to
the well-being of plants themselves than do the
colours of gems and minerals," Mr. Wallace proceeds
thus : —

"We may also include in the same category those algae
and fungi which have bright colours— the red snow of the
Arctic regions, the red, green, or purple seaweeds, the brilliant
scarlet, yellow, white or black agarics, and other fungi. All
these colours are probably the direct results of chemical com-
position or molecular structure, and being thus normal products
of the vegetable organism, need no special explanation from
our present point of view; and the same remark will apply
to the varied tints of the bark of trunks, branches and twigs,
which are often of various shades of brown and green, or
even vivid reds and yellows'."

Here, as Mr. Gulick has already observed, " Mr.
Wallace seems to admit that instead of useless specific
characters being unknown, they are so common and
so easily explained by ' the chemical constitution of
the organism ' that they claim no special attention ^."

* Darwinism, p. 302.

"^ American Journal of Science, Vol. XL. art. I. on The Inconsistencies
of Utilitarianism as the Exclusive Theory of Organic Evolution.

II. T

274 Darwin^ and after Darwin,

And whatever answer Mr. Wallace may make to this
criticism, I do not see how he is to meet the point at
present before us— namely, that, upon his own show-
ing, there are in nature numberless instances of
" characters which are useless without being hurtful,"
and which nevertheless present absolute *' constancy."
If, in order to explain the contradiction, he should fall
back upon the principle of correlation, the case would
not be in any way improved. For, here again, if the
term correlation were extended so as to include "the
chemical constitution or the molecular structure of
the organism," it would thereby be extended so as to
discharge all Darwinian significance from the term.

Summary,

I will conclude this discussion of the Utility
question by recapitulating the main points in an
order somewhat different from that in which they
have been presented in the foregoing chapters. Such
a variation may render their mutual connexions more
apparent. But it is only to the main points that
allusion will here be made, and, in order the better
to show their independent character, I will separately
number them.

1. The doctrine of utility as universal, whether
with respect to species only or likewise with respect
to specific characters, is confessedly an a priori
doctrine, deduced by way of general reasoning from
the theory of natural selection.

2. Being thus founded exclusively on grounds of
deduction, the doctrine cannot be combated by any

Characters as Adaptive and Specific, 275

appeal to facts. For this question is not one of fact :
it is a question of reasoning. The treatment of our
subject matter is logical : not biological.

3. The doctrine is both universal and absolute.
According to one form of it all species, and according
to another form of it all specific characters, must
necessarily be due to the principle of utility.

4. The doctrine in both its forms is deduced from
a definition of the theory of natural selection as
a theory, and the sole theory, of the origin of species :
but, as Professor Huxley has already shown, it does
not really follow, even from this definition, that all
specific characters must be "necessarily useful."
Hence the two forms of the doctrine, although coin-
cident with regard to species, are at variance with
one another in respect of specific characters. Thus
far, of course, I agree with Professor Huxley ; but
if I have been successful in showing that the above
definition of the theory of natural selection is logically
fallacious, it follows that the doctrine in both its
forms is radically erroneous. The theory of natural
selection is not, accurately speaking, a theory of the
origin of species: it is a theory of the origin and
cumulative development of adaptations, to whatever
order of taxonomic division these may happen to
belong. Thus the premisses of the deduction which
we are considering collapse : the principle of utility
is shown not to have any other or further reference
to species, or to specific characters, than it has to
fixed varieties, genera, families, &c., or to the char-
acters severally distinctive of each

5. But, quitting all such antecedent considera-
tions, we next proceeded to examine the doctrine

T 2

276 Darwin^ and after Darwin.

a posteriori, taking the arguments which have been
advanced in favour of the doctrine, other than those
which rest upon the fallacious definition. These
arguments, as presented by Mr. Wallace, are two in
number.

First, it is represented that natural selection must
occupy the whole field, because no other principle
of change can be allowed to operate in the presence
of natural selection. Now I fully agree that this
statement holds as regards any principle of change
which is deleterious, but I cannot agree that it does
so as regards any such principle which is merely
neutral. No reason has ever been shown why natural
selection should interfere with " indifferent " characters
— to adopt Professor Huxley's term— supposing such
to have been produced by any of the agencies which
we shall presently have to name. Therefore this
argument— or rather assertion— goes for nothing.

Mr. Wallace's second argument is, that utility is
the only principle which can endow specific characters
with their characteristic stability. But this again
is mere assertion. Moreover, it is assertion opposed
alike to common sense and to observable fact. It
is opposed to common sense, because it is obvious
that any other principle would equally confer stability
on characters due to it, provided that its action is
constant, as Darwin expressly held. Again, this
argument is opposed to fact, because we know of
thousands of cases where peculiar characters are
stable, which, nevertheless, cannot possibly be due
to natural selection. Of such are the Porto Santo
rabbits, the niata cattle, the ducks in St. James'
Park, turkeys, dogs, horses, &c., and, in the case of

Characters as Adaptive and Specific, 277

plants, wheat, cabbage, maize, &c., as well as all
the hosts of climatic varieties, both of animals and
plants, in a state of nature. Indeed, on taking a
wide survey of the facts, we do not find that the
principle of utility is any better able to confer
stability of character than are many other principles,
both known and unknown. Nay, it is positively less
able to do so than are some of these other principles.
Darwin gives two very probable reasons for this
fact ; but I need not quote them a second time. It
is enough to have seen that this argument from
stability 01; constancy is no less worthless than the
previous one. Yet these are the only two arguments
of a corroborative kind which Mr. Wallace adduces
whereby to sustain his " necessary deduction."

6. At this point, therefore, it may well seem that
we need not have troubled ourselves any further
with a generalization which does not appear to have
anything to support it. And to this view of the
case I should myself agree, were it not that many
naturalists now entertain the doctrine as an essential
article of their Darwinian creed. Hence, I proceeded
to adduce considerations per contra.

Seeing that the doctrine in question can only rest
on the assumption that there is no cause other than
natural selection which is capable of originating any
single species — if not even so much as any single
specific character — I began by examining this assump-
tion. It was shown first that, on merely antecedent
grounds, the assumption is '* infinitely precarious."
There is absolutely no justification for the state-
ment that in all the varied and complex processes of
organic nature natural selection is the only possible

278 Darwin, and after Darwin,

cause of specific change. But, apart altogether
from this a priori refutation of the dogma, our
analysis went on to show that, in point of actual
fact, there are not a few well-known causes of high
generality, which, while having no connexion with
the principle of utility, are demonstrably capable
of originating species and specific characters — if by
'* species " and " specific characters " we are to under-
stand organic types which are ranked as species,
and characters which are described as diagnostic
of species. Such causes I grouped under five dif-
ferent headings, viz. Climate^ Food, Sexual Selection,
Isolation, and Laws of Growth. Sexual Selection
and Isolation are, indeed, repudiated by Mr. Wallace ;
but, in common I believe with all biologists, he
accepts the other three groups of causes as fully
adequate to produce such kinds and degrees of
modification as are taken to constitute specific dis-
tinction. And this is amply sufficient for our present
purposes. Besides, under the head of Sexual Selection,
it does not signify in the present connexion whether
or not we accept Darwin's theory on this subject.
For, in any case, the facts of secondary sexual char-
acters are indisputable : these characters are, for the
most part, specific characters: and they cannot be
explained by the principle of utility. Even Mr.
Wallace does not attempt to do so ; and the ex-
planation which he does give is clearly incompatible
with his doctrine touching the necessarily life-serving
value of all specific characters. Lastly, the same has
to be said of the Laws of Growth. For we have just
seen that on the grounds of this principle likewise
Mr. Wallace abandons the doctrine in question. As

Characters as Adaptive and Specific. 279

regards Isolation, much more remains to be said in
the ensuing portion of this work, while, as regards
Climatic Variation, there are literally innumerable
cases where changes of specific type are known to
have been caused by this means.

7. To the latter class of cases, however, it will be
objected that these changes of specific type, although
no doubt suflficiently '* stable '' so long as the changed
conditions remain constant, are found by experiment
not to be hereditary ; and this clearly makes all the
difference between a true specific change and a merely
fictitious appearance of it.

Well, in the first place, this objection can have
reference only to the first two of the five principles
above stated. It can have no reference to the last
three, because of these heredity constitutes the very
foundation. This consideration ought to be borne in
mind throughout. But now, in the second place, even
as regards changes produced by climate and food, the
reply is nugatory. And this for three reasons, as
follows.

{a) No one is thus far entitled to conclude against
the possible transmission of acquired characters ; and,
so long as there is even so much as a possibility of
climatic (or any other admittedly non-utilitarian)
variations becoming in this way hereditary, the reply
before us merely begs the question.

{b) Even supposing, for the sake of argument, that
acquired characters can never in any case become
congenital, there remains the strong probability —
sanctioned as such even by Weismann — that changed
conditions of life may not unfrequently act upon the
material of heredity itself, thus giving rise to specific

28o Darwifiy and after Darwin,

changes which are from the first congenital, though
not utilitarian. Indeed, there are not a few facts
(Hoffmann's plants, Weismann's butterflies, &c.),
which can only be explained either in this way, or
as above (a). And in the present connexion it is
immaterial which of these alternative explanations
we choose to adopt, seeing that they equally
refute our opponents' objection. And not only
do these considerations— (^) and {h) — refute this
particular objection ; they overturn on new and
independent grounds the whole of our opponents'
generalization. For the generalization is, that the
principle of utility, acting through natural selection,
is " necessarily " the sole principle which can be
concerned in hereditary changes of specific type.
But here we perceive both a possibility [a] and a
probability (3), if not indeed a certainty, that quite
other principles have been largely concerned in the
production of such changes.

(c) Altogether apart from these considerations,
there remains a much more important one. For
the objection that fixed — or "stable" — climatic
varieties differ from true species in not being sub-
ject to heredity, raises the question — What are we
to understand by a " species " ? This question, which
was thus far purposely left in abeyance, had now
to be dealt with seriously. For it would clearly
be irrational in our opponents to make this highly
important generalization with regard to species and
specific characters, unless they are prepared to tell
us what they mean by species, and therefore by
characters as specific. In as far as there is any
ambiguity on this point it makes entirely for our

Characters as Adaptive and Specific. 281

side in the debate, because even any small degree
of uncertainty with regard to it would render the
generalization in question proportionally unsound.
Yet it is notorious that no word in existence is more
vague, or more impossible to define, than the word
"species." The very same men who at one time
pronounce their great generalization with regard to
species, at another time asseverate that "a species
is not a definite entity/' but a merely abstract term,
serving to denote this that and the other organic type,
which this that and the other systematist regards
as deserving such a title. Moreover it is acknow-
ledged that systematists differ among themselves
to a wide extent as to the kinds and degrees of
peculiarity which entitle a given form to a specific
rank. Even in the same department of systematic
work much depends on merely individual taste, while
in different departments widely different standards
of delimination are in vogue. Hence, our reductio
ad absurdum consists in this — that whether a given
form is to be regarded as necessarily due to natural
selection, and whether all its distinctive characters
are to be regarded as necessarily utilitarian characters,
will often depend on whether it has been described by
naturalist A or by naturalist B. There is no one
criterion — there is not even any one set of criteria —
agreed upon by naturalists for the construction of
specific types. In particular, as regards the principle
of heredity, it is not known of one named species
in twenty — probably not in a hundred — whether its
diagnostic characters are hereditary characters ; while,
on the other hand, even in cases where experiment
has proved " constant varieties " to be hereditary —

282 Darwifiy and after Darwin,

and even also cross-sterile with allied varieties — it is
only some three or four living botanists who for these
reasons advocate the elevation of such varieties to
the rank of species. In short, as we are not engaged on
any abstract question touching the principles on which
species ought to have been constituted by their makers,
but upon the actual manner in which they have been,
the criterion of heredity must needs be disregarded in
the present discussion, as it has been in the work of
systematists. And the result of this is, that any
objection to our introducing the facts of climatic varia-
tion in the present discussion is excluded. In par-
ticular, so far as any question of heredity is concerned,
all these facts are as assuredly as they are cogently
relevant. It is perfectly certain that there is " a large
proportional number " of named species — particularly
of plants; — which further investigation would resolve
into climatic varieties. With the advance of know-
ledge, "bad species" are always increasing at the
expense of "good species," so that we are now justified
in concluding with Kerner, Hackel, and other naturalists
best qualified to speak on this subject, that if we could
know as much about the past history and present rela-
tions of the remaining good species as we do about the
bad, all the former, without exception, would become
resolved into the latter. In point of fact, and apart
altogether from the inductive experience on which this
conclusion is based, the conclusion follows " as a neces-
sary deduction " from the general theory of descent.
For this theory essentially consists in supposing
either the past or the present existence of interme-
diate varietal forms in all cases, with the consequence
that *' good species " serve merely to mark lacunae in

Characters as Adaptive and Specific. 283

our knowledge of what is everywhere a finely gradu-
ated process of transmutation. Hence, if we place
this unquestionably " necessary deduction " from
the general theory of descent side by side with the
alleged "necessary deduction" from the theory of
natural selection, we cannot avoid the following
absurdity — Whether or not a given form is to be
regarded as necessarily due to natural selection,
and all its characters necessarily utilitarian, is to be
determined, and determined solely, by the mere
accident of our having found, or not having found,
either in a living or in a fossil state, its varietal
ancestry.

8. But this leads us to consider the final and
crowning incongruities which have been dealt with in
the present chapter. For here we have seen, not
only that our opponents thus draw a hard and fast
line between "varieties" and "species" in regard
to " necessary origin " and '* necessary utility," but that
they further draw a similar line between "species"
and '* genera " in the same respects. Yet, in ac-
cordance with the general theory of evolution, it is
plainly as impossible to draw any such line in the
one case as it is to do so in the other. Just as
fixed varieties are what Darwin called " incipient
species," so are species incipient genera, genera
incipient families, and so on. Evolutionists must
believe that the process of evolution is everywhere
the same. Nevertheless, while admitting all this, the
school of Huxley contradicts itself by alleging some
unintelligible exception in the case of *' species," while
the school of Wallace presses this exception so as to
embrace " specific characters." Indeed Mr. Wallace,

284 DarwiUy and after Darwin.

while maintaining that all specific characters must
necessarily be useful, maintains at the same time
that any number of varietal characters on the one
hand, and a good half of generic characters on
the other, are probably useless. Thus he contra-
dicts his argument from the "constancy of specific
characters" (seeing that generic characters are still
more constant), as later on we saw that he contra-
dicts his deductive generalization touching their
necessary utility, by giving a non-utilitarian ex-
planation of whole multitudes of specific characters.
I need not, however, again go over the ground so
recently traversed ; but will conclude by once more
recurring to the only explanation which I have
been able to devise of the otherwise inexplicable
fact, that in regard to this subject so many natural-
ists still continue to entangle themselves in the
meshes of absurdity and contradiction.

The only conceivable explanation is, that these
naturalists have not yet wholly divested themselves
of the special creation theory. Although professing
to have discarded the belief that '* species" are
" definite entities," differing in kind from " varieties "
on the one Kand and from "genera" on the other,
these writers are still imbued with a vague survival
of that belief. They well know it to belong to the
very essence of their new theory that "species"
are but *' pronounced varieties," or, should we prefer
it. "incipient genera"; but still they cannot alto-
gether escape the pre-Darwinian conception of species
as organic units, whose single mode of origin need
not extend to other taxonomic groups, and whose

Characters as Adaptive and Specific. 285

characters therefore present some exceptional signifi-
cance to the scientific naturalist. So to speak, such
divinity doth still hedge a species, that even in the
very act of declaring it but an idol of their own
creation, these naturalists bow before their fetish as
something that is unique — differing alike in its origin
and in its characters from the varieties beneath and
the genera above. The consequence is that they
have endeavoured to reconcile these incompatible
ideas by substituting the principle of natural selec-
tion for that of super-natural creation, where the
particular case of "species" is concerned In this
way, it vaguely seems to them, they are able to
save the doctrine of some one mode of origin as
appertaining to species, which need not " necessarily "
appertain to any other taxonomic division. All
other such divisions they regard, with their pre-
Darwinian forefathers, as merely artificial construc-
tions ; but, likewise with these forefathers, they look
upon species as natural divisions, proved to be such
by a single and necessary mode of origin. Hence,
Mr. Wallace expressly defines a species with reference
to this single and necessary mode of origin {see above,
p. 235), although he must be well aware that there is
no better, or more frequent, proof of it in the case
of species, than there is in that of somewhat less
pronounced types on the one hand (fixed varieties),
or of more pronounced types on the other (genera,
families, &c.). Hence, also, the theory of natural
selection is defined as par excellence a theory of the
origin of species ; it is taken as applying to the
particular case of the origin of species in a peculiarly
stringent manner, or in a manner which does not

286 Darwin^ and after Darwin.

apply to the origin of any other groups. And
I believe that an important accessory reason of the
continuance of this view for more than thirty years
after the publication of the Origin of Species by means
of Natural Selection, is to be found in the title of that
work. " Natural Selection " has thus become verbally
associated with " Origin of Species," till it is thought-
lessly felt that, in some way or another, natural selec-
tion must have a peculiar reference to those artificially
delineated forms which stand anywhere between
a fixed variety and a so-called genus. This verbal
association has no doubt had the effect of still further
preserving the traditional halo of mystery which clings
to the idea of a " species." Hence it comes that the
title which Darwin chose — and, looking to the circum-
stances of the time, wisely chose — for his great work,
has subsequently had the effect of fostering the very
idea which it was the object of that work to dissipate,
namely, that species are, peculiar entities, which differ
more or less in origin or kind from all other taxonomic
groups. The full title of this work is — The Origin of
Species by means of Natural Selection : or the Preserva-
tion of Favoured Races in the Struggle for Life. Now,
supposing that instead of this its author had chosen
some such title as the following: — The Origin of
Organic Types by means of Adaptive Evolution : or
Survival of the Fittest Forms in the Struggle for Life.
Of course this would have been a bad substitute from
various points of view ; but could any objection have
been urged against it from our present point of view ?
I do not see that there could. Yet, if such had been
the title, I have little doubt that we should never have
heard of those great generalizations with regard to

Characters as Adaptive and Specific. 287

species and specific characters, the futility of which it
has been the object of these chapters to expose.

In conclusion, it only remains to reiterate that in
thus combating what appears to me plainly errone-
ous deductions from the theory of natural selection,
I am in no wise combating that theory itself. On
the contrary, I hope that I am rendering it no unim-
portant service by endeavouring to relieve it of
a parasitic growth — an accretion of false logic.
Regarding as I do the theory of natural selection as,
primarily, a theory of the origin (or cumulative
development) of adaptations, I see in merely non-
adaptive characters-^ be they "specific" or other —
a comparatively insignificant class of phenomena,
which may be due to a great variety of incidental
causes, without any further reference to the master-
principle of natural selection than that in the presence
of this principle none of these non-adaptive characters
can be actively deleterious. But that there may be
" any number of indifferent characters " it is no part
of the theory of natural selection to deny ; and all
attempts to foist upon it apriori " deductions " opposed
alike to the facts of nature and to the logic of
the case, can only act to the detriment of the great
generalization which was expressly guarded from such
fallacies by the ever-careful judgement of Darwin.

APPENDICES AND NOTES

n.

APPENDIX I.

On Panmixia.

There are several points of considerable theoretical im-
portance connected with Panmixia, which were omitted
from the text, in order to avoid distracting attention from
the main issue which is there under consideration. These
side issues may now be appropriately presented in the form
in which they were published in Nature, March 13, 1890 ^
After stating, in almost the same words, what has already
been said in Chapter X, this paper proceeds, with the excep-
tion of a few verbal alterations, as follows.

"There is, however, one respect in which Professor Weismann's
statement of the principle of panmixia differs from that which was
considered by Mr. Darwin ; and it is this difference of statement
— which amounts to an important difference of theory— that I
now wish to discuss.

" The difference in question is, that while Professor Weismann
believes the cessation of selection to be capable of inducing de-
generation down to the almost complete disappearance of a rudi-
mentary organ, I have argued that, unless assisted by some other
principle, it can at most only reduce the degenerating organ to
considerably above one-half its original size— or probably not
through so much as one-quarter. The ground of this argument
(which is given in detail in the Nature articles of 1 873-1 874) is,
that panmixia depends for its action upon fortuitous variations
round an ever-diminishing average— the average thus diminish-
ing because it is no longer sustained by natural selection. But
although no longer sustained by natural selection^ it does con-
* Vol. xli. p. 438.

U 2 ,

292 DarwiHy and after Darwin,

tinue to be sustained by heredity ; and therefore, as long as the
force of heredity persists unimpaired, fortuitous variations alone—
or variation which is no longer controlled by natural selection —
cannot reduce the dwindling organ to so much as one-half of
its original size ; indeed, as above foreshadowed, the balance
between the positive force of heredity and the negative effects
of promiscuous variability will most likely be arrived at above
the middle line thus indicated. Only if for any reason the
force of heredity begins to fail can the average round which the
cessation of selection works become a progressively diminishing
average. In other words, so long as the original force of heredity
as regards the useless organ remains unimpaired, the mere with-
drawal of selection cannot reduce the organ much below the level
of efficiency above which it was previously maintained by the
f)resence of selection. If we take this level to be 80 or 90 per
cent, of the original size, cessation of selection will reduce the
organ through the 10 or 20 per cent., and there leave it fluc-
tuating about this average, unless for any reason the force of
heredity begins to fail — in which case, of course, the average will
progressively fall in proportion to the progressive weakening
of this force.

" Now, according to my views, the force of heredity under such
circumstances is always bound to fail, and this for two reasons.
In the first place, it must usually happen that when an organ
becomes useless, natural selection as regards that organ will not
only cease ^ but become reversed. For the organ is now absorbing
nutriment, causing weight, occupying space, and so on, uselessly.
Hence, even if it be not also a source of actual danger, ' economy
of growth ' will determine a reversal of selection against an organ
which is now not merely useless, but deleterious. And this de-
generating influence of the reversal of selection will throughout be
assisted by the cessation of selection, which will now be always
acting round a continuously sinking average. Nevertheless,
a point of balance will eventually be reached in this case, just as
it was in the previous case where the cessation of selection was
supposed to be working alone. For, where the reversal of selec-
tion has reduced the diminishing organ to so minute a size that
its presence is no longer a source of detriment to the organism,
the cessation of selection will carry the reduction a small degree

Appendix L 293

further; and then the organ will remain as a 'rudiment.* And
so it will remain permanently, unless there be some further reason
why the still remaining force of heredity should be abolished.
This further (or second) reason I found in the consideration that,
however enduring we may suppose the force of heredity to be, we
cannot suppose that it is actually everlasting; and, therefore,
that we may reasonably attribute the eventual disappearance of
rudimentary organs to the eventual failure of heredity itself. In
support of this view there is the fact that rudimentary organs,
although very persistent, are not everlasting. That they should
be very persistent is what we should expect, if the hold which
heredity has upon them is great in proportion to the time during
which they were originally useful, and thus firmly stamped upon
the organization by natural selection causing them to be strongly
inherited in the first instance. For example, we might expect
that it would be more difficult finally to eradicate the rudiment of
a wing than the rudiment of a feather ; and accordingly we find
it a general rule that long-enduring rudiments are rudiments of
organs distinctive of the higher taxonomic divisions— i.e. of
organs which were longest in building up, and therefore longest
sustained in a state of working efficiency.

" Thus, upon the whole, my view of the facts of degeneration
remains the same as it was when first published in these columns
seventeen years ago, and may be summarized as follows.

" The cessation of selection when working alone (as it probably
does during the first centuries of its action upon structures
or colours which do not entail any danger to, or perceptible drain
upon, the nutritive resources of the organism) cannot cause de-
generation below, probably, some lo to 20 per cent. But if from
the first the cessation of selection has been assisted by the
reversal of selection (on account of the degenerating structure
having originally been of a size sufficient to entail a perceptible
drain on the nutritive resources of the organism, having now
become a source of danger, and so forth), the two principles
acting together will continue to reduce the ever-diminishing
structure down to the point at which its presence is no longer
a perceptible disadvantage to the species. When that point is
reached, the reversal of selection will terminate, and the cessation
of selection will not then be able of itself to reduce the organ

294 DarwiUy and after Darwin,

through more than at most a very few further percentages of its
original size. But, after this point has been reached, the now
total absence of selection, either for or against the organ, will
sooner or later entail this further and most important consequence,
a failure of heredity as regards the organ. So long as the
organ was of use, its efficiency was constantly maintained by
the /r^j'<??/^^ of selection — which is merely another way o: saying
that selection was constantly maintaining the force of heredity as
regards that organ. But as soon as the organ ceased to be of
use, selection ceased to maintain the force of heredity; and thus,
sooner or later, that force began to waver or fade. Now it is
this wavering or fading of the force of heredity, thus originally
due to the cessation of selection, that in turn co-operates with
the still continued cessation of selection in reducing the structure
below the level where its reduction was left by the actual reversal
of selection. So that from that level downwards the cessation
of selection, and the consequent failing of heredity, act and react
in their common work of causing obsolescence. In the case of
newly added characters, the force of heredity will be less than
in that of more anciently added characters ; and thus we can
understand the long endurance of * vestiges ' characteristic
of the higher taxonomic divisions, as compared with those
characteristic of the lower. But in all cases, if time enough be
allowed under the cessation of selection, the force of heredity
will eventually fall to zero, when the hitherto obsolescent structure
will finally become obsolete. In cases of newly added and
comparatively trivial characters, with regard to which reversal
of selection is not likely to take place (e.g. slight differences of
colour between allied species), cessation of selection is likely to
be very soon assisted by a failure in the force of heredity ; seeing
that such newly added characters will not be so strongly
inherited as are the more ancient characters distinctive of higher
taxonomic groups.

" Let us now turn to Weismann*s view of degeneration. First
of all, he has omitted to perceive that ' panmixia ' alone (if un-
assisted either by reversed selection or an inherent diminishing
of the force of heredity) cannot reduce a functioniess organ
to the condition of a rudiment. Therefore he everywhere
represents panmixia (or the mere cessation of selection) as of

Appendix I. 295

itself sufficient to cause degeneration, say from too to 5, instead
of from 100 to 90 or 80, which, for the reasons above given,
appeared (and still appears) to me about the most that this
principle can accomplish, so long as the original force of heredity
continues unimpaired. No doubt we have here what must be
regarded as a mere oversight on the part of Professor Weis-
mann; but the oversight is rendered remarkable by the fact
that he does invoke the aid of reversed selection in order to
explain the final disappearance of a rudiment. Yet it is self-
evident that the reversal of selection must be much more active
during the initial than during the final stages of degeneration,
seeing that, ex hypothesis the greater the degree of reductionr
which has been attained the less must be the detriment arising
from any useless expenditure of nutrition, &c.

" And this leads me to a second oversight in Professor Weis-
mann's statement, which is of more importance than the first.
For the place at which he does invoke the assistance of reversed
selection is exactly the place at which reversed selection must
necessarily have ceased to act. This place, as already ex-
plained, is where an obsolescent organ has become rudimentary,
or, as above supposed, reduced to 5 per cent, of its original size ;
and the reason why he invokes the aid of reversed selection at
this place is in order to save his doctrine of * the stability of
germ-plasm.' That the force of heredity should finally become
exhausted if no longer maintained by the presence of selection,
is what Darwin's theory of perishable gemmules would lead
us to expect, while such a fact would be fatal to Weismnnn's
theory of an imperishable germ-plasm. Therefore he seeks to
explain the eventual failure of heredity (which is certainly a fact)
by supposing that after the point at which the cessation of selec-
tion alone can no longer act (and which his first oversight has
placed some 80 per cent, too low), the reversal of selection will
begin to act directly against the force of heredity as regards the
diminishing organ, until such direct action of reversed selection
will have removed the organ altogether. Or, in his own words,
* The complete disappearance of a rudimentary organ can only
take place by the operation of natural selection; this principle
will lead to its diminution, inasmuch as the disappearing struc-
ture takes the place and the nutriment of other useful and im-

296 Darwin, and after Darwin,

portant organs.* That is to say, the rudimentary organ finally
disappears, not because the force of heredity is finally exhausted,
but because natural selection has begun to utilize this force
against the continuance of the organ— always picking out those
congenital variations of the organ which are of smallest size, and
thus, by its now reversed action, reversing the force of heredity
as regards the organ.

" Now the oversight here is in not perceiving that the smaller
the disappearing structure becomes, the less hold must *this
principle' of reversed selection retain upon it. As above
observed, during the earlier stages of reduction (or while co-
operating with the cessation of selection) the reversal of selec-
tion will be at its juaximtnn of efficiency ; and, as the process
of diminution continues, a point must eventually be reached at
which the reversal of selection can no longer act. Take the
original mass of a now obsolescent organ in relation to that
of the entire organism of which it then formed a part to be
represented by the ratio i : 100. For the sake of argument we
may assume that the mass of the organism has throughout
remained constant, and that by ' mass ' in both cases is meant
capacity for absorbing nutriment, causing weight, occupying
space, and so forth. Now, we may further assume that when
the mass of the organ stood to that of its organism in the ratio
of 1 : 100, natural selection was strongly reversed with respect
to the organ. But when this ratio fell to i : 1000, the activity of
such reversal must have become enormously diminished, even
if it still continued to exercise any influence at all. For we must
remember, on the one hand, that the reversal of selection can
only act as long as the presence of a diminishing organ con-
tinues to be so injurious that variations in its size are matters of
life and death in the struggle for existence ; and, on the other
hand, that natural selection in the case of the diminishing organ
does not have reference to the presence and the absence of the
organ, but only to such variations in its mass as any given
generation may supply. Now, the process of reduction does
not end even at i : 1000. It goes on to i : 10,000, and eventually
I : oc. Consequently, however great our faith in natural selec-
tion may be, a point must eventually come for all of us at which
we can no longer believe that the reduction of an obsolescent

Appendix L 297

organ is due to reversed selection. And I cannot doubt that if
Professor Weismann had sufficiently considered the matter, he
would not have committed himself to the statement that * the
complete disappearance of a rudimentary organ can only take
place by the operation of natural selection'

" According to my view, the complete disappearance of a rudi-
mentary organ can only take place by the cessation of natural
-selection, which permits the eventual exhaustion of heredity,
when heredity is thus simply left to itself. During all the earlier
stages of reduction, the cessation of selection was assisted in its
work by the reversal of selection ; but when the rudiment
became too small for such assistance any longer to be supplied,
the rudiment persisted in that greatly reduced condition until
the force of heredity with regard to it was eventually worn
out. This appears to me, as it appeared in 1873, the only
reasonable conclusion that can be drawn from the facts. And
it is because this conclusion is fatal to Professor Weismann's
doctrine of the permanent * stability ' of germ-plasm, while
quite in accordance with all theories which belong to the family
of pangenesis, that I deem the facts of degeneration of great
importance as tests between these rival interpretations of the
facts of heredity. It is on this account that I have occupied so
much space with the foregoing discussion ; and I shall be glad
to ascertain whether any of the followers of Professor Weismann
are able to controvert these views.

" George J. Romanes.'^

"P.S. — Since the above article was sent in, Professor Weismann
has published in these columns (February 6) his reply to a criti-
cism by Professor Vines (October 24, 1889). In this reply
he appears to have considerably modified his views on the
theory of degeneration ; lor while in his Essays he says (as in
the passage above quoted) that * the complete disappearance of
a rudimentary organ can only take place by the operation
of natural selection' — i.e. only by the reversal of selection, — in
his reply to Professor Vines he says, * I believe that I have
proved that organs no longer in use become rudimentary, and
must" finally disappear, solely by ''panmixia"; not through the
direct action of disuse, but because natural selection no longer

298 Darwin, arid after Darwin,

sustains their standard structure' — i.e. solely by the cessation
of selection. Obviously, there is here a flat contradiction. If
Professor Weismann now believes that a rudimentary organ
*must finally disappear solely^ through the withdrawal of
selection, he has abandoned his previous belief that *the
complete disappearance of a rudimentary organ can only take
place by the operation of selection. ' And this change of belief
on his part is a matter of the highest importance to his system
of theories as a whole, since it betokens a surrender of his
doctrine of the *stabihty' of germ-plasm— or of the virtually
everlasting persistence of the force of heredity, and the
consequent necessity for a reversal of this force itself (by natural
selection placing its premium on minus instead of on plus
variations), in order that a rudimentary organ should finally
disappear. In other words, it now seems he no longer believes
that the force of heredity in one direction (that of sustaining
a rudimentary organ) can only be abolished by the active influence
of natural selection determining this force in the opposite
direction (that of removing a rudimentary organ). It seems he
now believes that the force of heredity, if merely left to itself
by the withdrawal of natural selection altogether, will sooner or
later become exhausted through the mere lapse of time. This,
of course, is my own theory of the matter as originally published
in these columns ; but I do not see how it is to be reconciled
with Professor Weismann's doctrine of so high a degree of
stability on the part of germ-plasm, that we must look to the
Protozoa and the Protophyta for the original source of congenital
variations as now exhibited by the Metazoa and Metaphyta.
Nevertheless, and so far as the philosophy of degeneration is
concerned, I shall be very glad if (as it now appears) Professor
Weismann's more recent contemplation has brought his principle
of panmixia into exact coincidence with that of my cessation
of selection."

Before passing on it may here be noted that, to any one
who believes in the inheritance of acquired characters, there
is open yet another hypothetical cause of defeneration, and
one to which the final disappearance of vestigial organs may
be allribuied. Roux has shown in his work on The Struggle

Appendix /. 299

for Existence between Parts of an Organism that the principle
of selection must operate in every constituent tissue, and as
between every constituent cell of which an organism is com-
posed. Now, if an organ falls into disuse, its constituent cells
become worsted in their struggles with other cells in the
organism. Hence, degeneration of the disused organ may
progressively increase, quite independently of any struggle
for existence on the part of the organism as a whole. Con-
sequently, degeneration may proceed without any reference
to the principle of " economized nutrition " ; and, if it does
so, and if the effects of its doing so are transmitted from
generation to generation, the disused organ will finally dis-
appear by means of Roux's principle.

The long communication above quoted led to a still longer
correspondence in the pages of Nature, For Professor Ray
Lankester wrote ^ to impugn the doctrine of panmixia,or cessa-
tion of selection, in toto^ arguing with much msistence that
" cessation of selection must be supplemented by economy of
growth in orc'er to produce the results attributed to panmixia.**
In other words, he denied that panmixia alone can cause
degeneration in any degree at all : at most, he said, it can
be but " a condition,*' or ** a state," which occurs when an
organ or part ceases to be useful, and therefore falls under
the degenerating influence of active causes, such as economy
of nutrition. Or, in yet other words, he refused to recognize
that any degenerative process can be due to natural selection
as merely withdrawn : only when, besides being withdrawn,
natural seleciion is reversed, did he regard a degenerative
process as possible. As a result of the correspondence,
however, he eventually '^ agreed that, if thc^ " birth-mean *' of
an organ, in respect either of size or complexity of structure,
be lower than the '* seleciion-mean ** while the organ is useful
(a fact which he does not dispute) ; then, if the organ ceases

' Nature, vol xli. p. 486. ' Ibid. vol. xlii. p. «>2,

300 Darwiriy and after Darwin,

to be useful, it will degenerate by the withdrawal of selection
alone. Which, of course, is merely a re- statement of the
doctrine of panmixia, or cessation of selection, in somewhat
varied terminology — provided that the birth-mean be taken
over a number of generations, or not only over a few follow-
ing the selection-mean of the structure while still in its
highest stale of efficiency. For the sake of brevity I will
hereafter speak of these " few following " generations by the
term of " first generations."

It remains to consider the views of Professor Lloyd
Morgan upon the subject. In my opinion he is the
shrewdest, as well as the most logical critic that we have
in the field of Darwinian speculation; therefore, if possible,
I should like to arrive at a full agreement with him upon
this matter. His latest utterance with regard to it is as
follows : —

"To account for the diminution of organs or structures
no longer of use, apart from any inherited effects of disuse,
Mr. Romanes has invoked the Cessation of Selection; and
Mr. Francis Galton has, in another connexion, summarized the
effects of this cessation of selection in the convenient phrase
* Regression to Mediocrity.' This is the Panmixia of Professor
Weismann and his followers; but the phrase regression to
mediocrity through the cessation of selection appears to me
preferable. It is clear that so long as any organ or structure
is subject to natural selection through elimination, it is, if not
actually undergoing improvement, kept at a high standard of
efficiency through the elimination of all those individuals in
which the organ in question falls below the required standard.
But if, from change in the environment or any other cause, the
character in question ceases to be subject to selection, elimina-
tion no longer takes place, and the high standard will no longer
be maintained. There will be reversion to mediocrity. The
probable amount of this reversion is at present a matter under
discussion '."

' Presidential Address to the Bristol Naturalist f Society, 1891.

Appendix I, 301

So far, then, Professor Lloyd Morgan is in complete
agreement with previous writers upon the subject. He does
not doubt that the cessation of selection must always be
a cause of degeneration : the only question is as to the
potency of this cause, or the amount of degeneration which
it is capable of effecting.

Taking, first, the case of bulk or size of an organ, as
distinguished from its organization or complexity, we have
seen that Weismann represents the cessation of selection —
even if working quite alone, or without any assistance from
the reversal of selection — to be capable of reducing a fully
developed organ to the state of a rudiment, or even, if we
take his most recent view, of abolishing the organ in toto.

Professor Lloyd Morgan, on the other hand, does not
think that the cessation of selection alone can cause reduc-
tion further than the level of "mediocrity" in the first
generations — or, which is much the same thing, further than
the difference between the " birth-mean " and the " selection-
mean " of the first generations. This amount of reduction
he puts at 5 per cent., as " a very liberal estimate."

Here, then, we have three estimates of the amount of
degeneration which can be produced by panmixia alone,
where mere size or bulk of an organ is concerned — say,
3 to 5 per cent., lo to 20 per cent., and 95 per cent, to o.
At first sight, these differences appear simply ludicrous;
but on seeking for the reasons of them, we find that they
are due to different views touching the manner in which
panmixia operates. The oversights which have led to
Weismann's extremely high estimate have already been
stated. The reason of the difference between the extremely
low estimate of Professor Lloyd Morgan, as compared with
my own intermediate one, is, that he supposes the power
of panmixia to become exhausted as soon as the level of
mediociity of the first generations has become the general
level in succeeding generations. In my view, however, the

302 Darwin^ and after Darwin,

level of mediocrity is itself a sinking level in successive
generations, with the result that there is no reason why the
reducing power of panmixia should ever become exhausted,
save that the more reduction it effects the greater is the
force of heredity which remains to be overcome, as
previously explained. Thus the only question between
Professor Lloyd Morgan and myself is — Does the level of
mediocrity fall in successive generations under the cessation
of selection, or does it remain permanently where it used to
be under the presence of selection ? Does the " birth-mean "
remain constant throughout any number of generations,
notwithstanding that the sustaining influence of selection
has been withdrawn ; or does it progressively sink as a con
sequence of such withdrawal ?

In order to answer this question we had better begin by
considering now the case of organization of structure, as
distinguished from mere size of structure. Take any case
where a complex organ — such as a compound eye — has been
slowly elaborated by natural selection, and is it not self-
evident that, when natural selection is withdrawn, the com-
plex structure will deteriorate ? In other words, the level of
mediocrity, say in the hundred thousandth generation after
the sustaining influence of natural selection has been with-
drawn, will not be so high as it was in the first generations.
For, by hypothesis, there is now no longer any elimination
of unfavourable variations, which may therefore perpetuate
themselves as regards any of the parts of this highly complex
mechanism ; so that it is only a matter of time when the
mechanism must become disintegrated. I can scarcely
suppose that any one who considers the subject will question
this statement, and therefore I will not say anything that
might be said in the way of substantiating it. But, if the
statement be assented to, it follows that there is no need to
look for any cause of deterioration, further than the with-
(irawal of selection — or cessation of the principle which (as

Appendix L 303

we are supposing) had hitherto been the sole means of

maintaining efficient harmony among all the independently
variable parts of the highly complex structure.

Now, I hold that the same thing is true, though in a lesser
degree, as regards degeneration of size. That there is no
difference in kind between the two cases. Professor Lloyd
Morgan implicitly allows ; for what he says is —

"In any long-established character, such as wing-power in
birds, brain-development, the eyes of Crustacea, &c., no short-
comer in these respects would have been permitted by natural
selection to transmit his shortcomings for hundreds of genera-
tions. All tendency to such shortcomings would, one would
suppose, have been bred out of the race. If after this long
process of selection there still remains a strong tendency to
deterioration, this tendency demands an explanation *."

Here, then, deterioration as to size of structure (wings of
birds), and deterioration as to complexity of structure (brain
and eyes) are expressly put upon the same footing. There-
fore, if in the latter case the "tendency to deterioration"
does not " demand an explanation," beyond the fact that the
hitherto maintaining influence has been withdrawn, neither
is any such further explanation demanded in the former case.
Which is exactly my own view of the matter. It is also
Mr. Galton's view. For although, in the passage formerly
quoted, Professor Lloyd Morgan appears to think that by the
phrase " Regression to Mediocrity " Mr. Galton means to
indicate that panmixia can cause degeneration only as far as
the mediocrity level of the first generations, this, in point of
fact, is not what Galton means, nor is it what he says. The
phrase in question occurs "in another connexion/* and,
indeed, in a different publication. But where he expressly
alludes to the cessation of selection, this is what he says.
The italics are mine.

* Presidential Address to the Bristol Naturalists^ Society, 1891.

304 Darwin^ and after Daruutn,

**A special cauce may be assigned for the effects of use in
causing hereditary atrophy of disused parts. It has already
been shown that all exceptionally developed organs tend to de-
teriorate : consequently, those that are not protected by selec-
tion will dwindle. The level of muscular efficiency in the wing
of a strongly flying bird [curiously enough, the same case that
is chosen by Professor Lloyd Morgan to illustrate his opposite
view], is like the level of water in the leaky vessel of a Danaid,
only secured to the race by constant effort^ so to speak. Let
the effort be relaxed ever so little^ and the level immediately
falls \"

I take it, then, that the burden of proof lies with Professor
Lloyd Morgan to show why the withdrawal of selection is
not sufficient to account for degeneration any further than
the mediocrity-level in the former presence of selection.
Why does "the strong tendency* to deterioration demand
an explanation," further than the fact that when all variations
below the average in every generation are allowed to survive,
they must gradually lower the average itself through a series
of generations ? To answer that any such tendency "would
have been bred out of the race " by the previous action of
selection, is to suppose that the function of selection is at an
end when once it has built up a structure to the highest
point of working efficiency, — that the presence of selection
is no longer required to maintain the structure at that point.
But it is enough to ask in reply — Why, under the cessation
of selection, does complexity of structure degenerate so
much more rapidly than size of structure ? Why is it, for
instance, that "the eyes of Crustacea" in dark caves have
entirely disappeared, while their foot-stalks (when originally
present) still remain? Can it be maintained that "for
hundreds of generations " natural selection was more intent

* A Theory of Heredity, Journal of Anthropological Institute, 1875.
Vol. V. p. 345.

^ No one has supposed that the tendency need be "strong": it has
only to be persistent.

Appendix /. 305

on developing the foot-stalks than the eyes which were
mounted upon them — so that while the latter were left by
selection with " a strong tendency to deterioration," the
former have had this tendency " bred out in the race " * ?

To sum up. There is now no question in any quarter
touching the fact that panmixia, or the cessation of selection,
is a true cause of degeneration. The only question is as to
the amount of degeneration which it is able to effect when
not assisted by the reversal of selection, or any other
cause of degeneration. Moreover, even with regard to this

* Of course it must be observed that degeneration of complexity
involves also degeneration of size, so that a more correct statement
of the case would be — Why, under the cessation of selection, does an
organ of extreme complexity degenerate much more rapidly than one of
much less complexity? For example, under domestication the brains
of rabbits and ducks appear to have been reduced in some cases by
as much as 50 per cent. (Darwin, and Sir !• Crichton Browne.) But
if it is possible to attribute this effect — or part of it — to an artificial
selection of stupid animals, I give in the text an example occurring
under nature. Many other cases, however, might be given to show the
general rule, that under cessation of selection complexity of structure
degenerates more rapidly — and also more thoroughly — than size of it.
This, of course, is what Mr. Galton and I should expect, seeing that the
more complex a structure the greater are the number of points for
deterioration to invade when the structure is no longer "protected by
selection." (On the other hand, of course, this fact is opposed to the
view that degeneration of useless structures below the "birth-mean" of
the first generations, is exclusively due to the reversal of selection ; for
economy of growth, deleterious effect of weight, and so forth, ought to
affect size of structure much more than complexity of it.) But I choose
the above case, partly because Professor Lloyd Morgan has himself
alluded to " the eyes of Crustacea," and partly because Professor Ray
Lankester has maintained that the loss of these eyes in dark caves is due
to the reversal of selection, as distinguished from the cessation of it. In
view of the above parenthesis it will be seen that the point is not of
much importance in the present connexion ; but it appears to me that
cessation of selection must here have had at least the larger share in the
process of atrophy. For while the economy of nutrition ought to have
removed the relatively \2i\^<t footstalks as rapidly as the eyes, I cannot
see that there is any advantage, other than the economy ot nutrition, to
be gained by the rapid loss ot hard- coated eyes^ even though they have
ceased to be of use.

II. X

3o6 Darwin^ and after Darwin.

question of amount, there is no doubt on any side that
panmixia alone causes degeneration more rapidly where it
has to do with complexity of organization, than it does where
it is concerned with a mere reduction of mass.

The question as to the amount of degeneration that is
caused by the cessation of selection alone is without any
practical importance where species in a state of nature are
concerned, because here the cessation of selection is probably
always associated more or less with the reversal of it ; and it
is as impossible as it is immaterial to determine the relative
shares which these two co-operating principles take in
bringing about the observed results. But where organisms
in a state of domestication are concerned, the importance of
the question before us is very great. For if the cessation of
selection alone is capable of reducing an organ through
lo or 12 per cent, of its original size, nearly all the direct
evidence on which Darwin relied in favour of use-inheritance
is destroyed. On the other' hand, if reduction through 5 per
cent, be deemed a " very liberal estimate " of what this
principle can accomplish, the whole body of Darwin's direct
evidence remains as he left it. I have now given my reasons
for rejecting this lower estimate on the one hand, and what
seems to me the extravagant estimate of Weismann on the
other. But my own intermediate estimate is enough to
destroy the apparent proof of use-inheritance that was given
by Darwin. Therefore it remains for those who deny
Lamarckian principles, either to accept some such estimate,
or else to acknowledge the incompatibility of any lower one
with the opinion that there is no evidence in favour of these
principles.

APPENDIX II.

On Characters as Adaptive and Specific.

It is the object of this Appendix to state, more fully than
in the text, the opinions with regard to this subject which
have been published by the two highest authorities on the
theory of natural selection — Darwin and Professor Huxley.
I will take first the opinion of Professor Huxley, quoted in
extenso, and then consider it somewhat more carefully than
seemed necessary in the text.

As far as I am aware, the only occasion on which
Professor Huxley has alluded to the subject in question, is in
his obituary notice of Darwin in the Proceedings of the Royal
Society, Vol. XLIV, No. 269, p. xviii. The allusion is to my
paper on Physiological Selection^ in the Journal of the
Linncean Society, Zool. Vol. XIX, pp. 33 7-4 11. But it will be
observed that the criticism has no reference to the theory
which it is the object of that paper to set forth. It refers
only to my definition of the theory of natural selection as
primarily a theory of the origin, or cumulative development,
of adaptations. This criticism, together with my answer
thereto at the time, is conveyed in the following words.

" Every variety which is selected into a species is favoured
and preserved in consequence of being, in some one or more
respects, better adapted to its surroundings than its rivals.
In other words, every species which exists, exists in virtue
of adaptation, and whatever accounts for that adaptation ac-
counts for the existence of the species. To say that Darwin

X 2

3o8 Darwin^ and after Darwin,

has put forward a theory of the adaptation of species, but not of
their origin, is therefore to misunderstand the first principles
of the theory. For, as has been pointed out, it is a necessary
consequence of the theory of selection that every species
must have some one or more structural or functional pecu-
liarities, in virtue of the advantage conferred by which it has
fought through the crowd of its competitors, and achieved a
certain duration. In this sense, it is true that every species
has been 'originated' by selection."

Now, in the first place, I have nowhere said that "Darwin
has put forward a theory of the adaptation of species, but not
of their origin." I said, and continue to say, that he has
put forward a theory of adaptations in general^ and that
where such adaptations appertain to species only (i.e. are
peculiar to particular species), the theory becomes ^^ also a
theory of the origin of the species which present them." The
only possible misunderstanding, therefore, which can here be
alleged against me is, that 1 fail to perceive it as a " necessary
consequence of the theory of selection that every species 7nust
have some one or more structural or i\mQ.'i\or\?\ peculiarities^^
of an adaptive or utilitarian kind. Now, if this is a misunder-
standing, I must confess to not having had it removed by
Mr. Huxley's exposition.

The whole criticism is tersely conveyed in the form t)f two
sequent propositions — namely, "Every species which exists,
exists in virtue of adaptation ; and whatever accounts for that
adaptation accounts for the existence of the species." My
answer is likewise two-fold. First, I do not accept the premiss ;
and next, even if I did, I can show that the resulting con-
clusion would not overturn my definition. Let us consider
these two points separately, beginning with the latter, as the
one which may be most briefly disposed of.

I. Provisionally conceding that " every species which exists,
exists in virtue of adaptation," I maintain that my definition
of the theoiy of natural selection still holds good. For even
on the basis of this concession, or on the ground of this
assumption, the theory of natural selection is not shown to be
*^ primarily " a theory of the origin of species. It iollows, indeed,
from the assumption — is, in fact, part and parcel ol the as-

Appendix II. 309

sumption — that all species have been originated by natural
selection; but why? Only because natural selection has origin-
ated those particular adaptive features in virtue of which {by the
hypothesis) species exist as species. It is only in virtue of having
created these features that natural selection has created the
species presenting them — ^just as it has created genera, families,
orders, &c., in virtue of other adaptive features extending through
progressively wider areas of taxonomic division. Everywhere
and equally this principle has been " primarily '* engaged in the
evolution of adaptations, and if one result of its work has
been that of enabling the systematist to trace lines of genetic
descent under his divisions of species, genera, and the rest,
such a result is but "secondary" or "incidental."

In short, it is '"'• pjimarily^^ a. theory of adaptations wher-
ever these occur, and only becomes " also^* or ^^ incidentally^'
a theory of species in cases where adaptations happen to be
restricted in their occurrence to organic types of a certain order
of taxonomic division.

II. Hitherto, for the sake of argument, I have conceded
that, in the words of my critic, " it is a necessary consequence
of the theory of selection that every species must have some
one or more structural or functional peculiarities" of an
adaptive kind. But now I will endeavour to show that this
statement does not " follow as a necessary consequence "
from "the theory of selection."

Most obviously " it follows " from the theory of selection that
" every variety which is selected into a species is favoured and
preserved in consequence of being, in some one or more
respects, better adapted to its surroundings than its rivals."
This, in fact, is no more than a re-statement of the theory
itself. But it does not follow that " every species which exists,
exists in virtue of adaptation" peculiar to that species \ i.e.
that every species which exists, exists in virtue of having
Ifeen *^ selected" This may or may not be true as a matter
of fact : as a matter of logic, the inference is not deducible
from the selection theory. Every variety which is ^^ selected
into** a species must, indeed, present some such peculiar
advantage ; but this is by no means equivalent to saying, " in
other words," that every variety which becomes a species

3IO Darwifiy and after Darwin,

must do so. For the latter statement imports a completely
new assumption — namely, that every variety which becomes
a species must do so because it has been " selected into " a
species. In short, what we are here told is, that if we believe
the selection principle to have given origin to some species,
we must further believe, "as a necessary consequence," that
it has given origin to all species.

The above reply, which is here quoted verbatim from
Nature, Vol. 38, p. 616-18, proceeded to show that it does
not belong to " the first principles of the theory of natural
selection " to deny that no other cause than natural selection
can possibly be concerned in the origin of species ; and facts
were given to prove that such unquestionably has been
the case as regards the origin of *' local " or " permanent "
varieties. Yet such varieties are what Darwin correctly
terms "incipient" species, or species in process of taking
origin. Therefore, if Professor Huxley's criticism is to stand
at all, we must accept it " as a necessary consequence of the
theory of selection," that every such variety " which exists,
exists in virtue of adaptation " — a statement which is proved
to be untrue by the particular cases forthwith cited. But as
this point has been dealt with much more fully in the text of the
present treatise, I shall sum up the main points in a few words.

The criticism is all embodied in two propositions — namely,
(a) that the theory of natural selection carries with it, as
a ** necessary consequence," the doctrine that survival of the
fittest has been the cause of the origin of all species ; and
(3) that therefore it amounts to one and the same thing
whether we define the theory as a theory of species or as
a theory of adaptations. Now, as a mere matter of logical
statement, it appears to me that both these propositions are
unsound. As regards the first, if we hold with Darwin that
other causes have co-operated with natural selection in the
origination of some (i. e. many) species, it is clearly no part
of the theory of natural selection to assume that none of

Appendix II, 311

these causes can ever have acted independently. In point
of fact, as we have seen in the foregoing chapters, such has
probably and frequently been the case under the influences
of isolation, climate, food, sexual selection, and laws of
growth ; but I may here adduce some further remarks with
regard to yet another possible cause. If the Lamarckian
principles are valid at all, no reason can be shown why in
some cases they may not have been competent 0/ themselves
to induce morphological changes of type by successive
increments, until a transmutation of species is effected by
their action alone — as, indeed, Weismann believes to have
been the case with all the species of Protozoa *. That such
actually has often been the case also with numberless species
of Metozoa, is the belief of the neo-Lamarckians ; and
whether they are right or wrong in holding this belief, it is
equally certam that, as a matter of logical reasoning, they are
not compelled by it to profess any disbelief in the agency of
natural selection. They may be mistaken as to the facts, as
Darwin in a lesser degree may have been similarly mistaken ;
but just as Darwin has nowhere committed himself to the
statement that all species must necessarily have been originated
by natural selection, so these neo-Lamarckians are perfectly
logical in holding that some species may have been wholly
caused by the inheritance of acquired characters, as other
species may have been wholly cau'^^d by the natural selection
of congenital characters. In short, unless we begin by
assuming (with Wallace and against Darwin) that there
can be no other cause of the origin of species than that which
is furnished by natural selection, we have no basis for
Professor Huxley's statement "that every species has been
originated by selection " ; while, if we do set out with this
assumption, we end in a mere tautology. What ought to
be done is to prove the validity of this assumption ; but, as

* Since the above was written Professor Weismann has transferred
this doctrine from the Protozoa to their ancestor!.

312 Darwin, and after Darwin,

Professor Huxley makes no attempt to do this, his criticism
amounts to mere begging of the question.

And now, as regards the second point (3), even if we grant
the assumption that natural selection is the only possible
cause of the origin of species — or, which is the same thing,
that every species has been originated by natural selection, — is
it likewise the same thing whether we define the theory of
natural selection as a theory of species or as a theory of
adaptations ? Professor Huxley's criticism endeavours to show
that it is ; but a little consideration is enough to show that it
is not. What does follow from the assumption is, that, so far
as specific characters are concerned, it is one and the same thing
to say that the theory is a theory of species, and to say that
it is a theory of adaptations. But specific characters are not
conterminous with adaptive characters; for innumerable
adaptive characters are not distinctive of species, but of
genera, families, orders, classes, and sub-kingdoms. There-
fore, if it is believed (as, of course. Professor Huxley
believes) that the theory in question explains the evolution
of all adaptive characters, obviously it is not one and the
same thing to define it indifferently as a theory of species or
as a theory of adaptations.

Now, all this is not merely a matter of logic chopping. On
the contrary, the question whether we are to accept or to
reject the deduction that all species must necessarily have
owed their origin to natural selection, is a question of no
small importance to the general theory of evolution. And
our answer to this question must be determined by that
which we give to the ulterior question— Is the theory of
natural selection to be defined as a theory of species, or
as a theory of adaptations ?

We now pass on to our consideration of Darwin's opinion
touching the question, as stated by himself, — " I'he doctrine
of utility, how far true ? " As I cannot ascertain that Darwin

I

Appendix II , 313

has anywhere expressed an opinion as to whether natural
selection has been necessarily concerned in the origin of all
species, the issue here is as to whether he held this with
regard to all specific characters. It will be remembered that
while opposing this doctrine as erroneous both in logic and
in fact, I have represented that it is not a doctrine which
Darwin sanctioned ; but, on the contrary, that it is one
which he expressly failed to sanction, by recognizing the
frequent inutility of specific characters. Mr. Wallace, on the
other hand, alleges that Darwin did believe in the universal —
as distinguished from the general — utility of such characters.
And he adds that he has " looked in vain in Mr. Darwin's
works " for any justification of my statements to the contrary ^
Therefore I will endeavour to show that Mr. Wallace's search
has not been a very careful one.

We must remember, however, that it was not until the
appearance of my paper on Physiological Selection, four
years after Darwin's death, that the question now in debate
was raised. Consequently, he never had occasion to deal
expressly with this particular question — viz. whether "the
doctrine of utility'* has any peculiar reference to specific
characters — as he surely would have done had he entertained
the important distinction between specific and all other
characters which Mr. Wallace now alleges that he did
entertain. But, be this as it may, we cannot expect
lO find in Darwin's writings any express allusion to a
question which had not been raised until 1886. The
most we can expect to find are scattered sentences which
])rove that the distinction in question was never so much
as present to his mind, — i.e. never occurred to him as
even a possible distinction.

* Darwinism, p. 131. He says: — "I have looked in vain in
Mr. Darwin's works for any such acknowledgement " (i.e. "that a large
proportion of specific distinctions must be conceded useless to the species
l^resenting them ").

314 Darwin^ and after Darwin.

I will first take the passages which Mr. Wallace him-
self supplies from among those which I had previously
indicated.

"But when, from the nature of the organism and of the
conditions, modifications have been induced which are unim-
portant for the welfare of the species, they may be, and ap-
parently often have been, transmitted in nearly the same state
to numerous, otherwise modified, descendants ^"

On this passage Mr. Wallace remarks that the last five
words "clearly show that such characters are usually not
' specific,' in the sense that they are such as distinguish
species from one another, but are found in numerous allied
species." But I cannot see that the passage shows anything
of the sort. What to my mind it does show is, {a) that
Mr. Darwin repudiated Mr. Wallace's doctrine touching the
necessary utility of all specific characters : (J)) that he takes
for granted the contrary doctrine touching the inutihty of
some specific characters: (r) that without in this place
alluding to the proportional number of useless specific
characters, he refers their origin in some cases to " the
nature of the organism" (i.e. "spontaneous variability" due
to internal causes), and in other cases to " the conditions '*
(i.e. variability induced by external causes): {cl) that when
established as a specific character by heredity, such a useless
character was held by him not to tend to become obsolete by
the influence of natural selection or any other cause ; but, on
the contrary, to be " transmitted in nearly the same state to
numerous, otherwise modified, descendants " — or progeny of
the species in genera, families, &c. : {e) and, therefore, that
useless characters which are now distinctive of genera,
families, &c., were held by him frequently, if not usually, to
point to uselessness of origin, when first they arose as merely
specific characters. Even the meaning which Mr. Wallace
reads into this passage must imply every one of these points ;
* Origin of Species, p. 175. Italics mine.

Appendix 11. 315

and therefore I do not see that he gains much by apparently
seeking to add this further meaning — viz. that in Darwin's
opinion there must have been some unassignable reason
preventing the occurrence of useless specific characters in
cases where species are not destined to become the parents
of genera.

Moreover, any such meaning is out of accordance with
the context from which the passage is taken. For, after
a long consideration of the question of utility, Darwin sums
up, — "We thus see that with plants many morphological
changes may be attributed to the laws of growth and the
interaction of parts, independently of natural selection^* And
then he adds, — " From the fact of the above characters being
unimportant for the welfare of the species, any slight variations
which occurred in them would not have been augmented
through natural selection.^' Again, still within the same
passage, he says, while alluding to the causes other than
natural selection which lead to changes of specific characters, —
"If the unknown cause were to act almost uniformly for
a length of time, we may infer that the result would be
almost uniform ; and in this case all the individuals of the
species would be modified in the same manner/' For my
own part I do not understand how Mr. Wallace can have
overlooked these various references to species, all of which
occur on the very page from which he is quoting. The
whole argument is to show that " many morphological
changes may be attributed to the laws of growth and the
inter-action of parts \^plus external conditions of life],
independently of natural selection " ; that such non-adaptive
changes, when they occur as " specific characters," may, if
the species should afterwards give rise to genera, families,
&c., become distinctive of these higher divisions. But there
is nothing here, or in any other part of Darwin's writings,
to countenance the inconsistent notion which Mr. Wallace
appears to entertain, — viz. that species which present useless

3i6 Darwifiy and after Darwin,

characters are more apt to give rise to genera, families, &c.,
than are species which do not present such characters.

The next passage which Mr. Wallace quotes, with his
comments thereon, is as follows. The italics are his.

"'Thus a large yet undefined extension may safely be given
to the direct and indirect results of natural selection ; but I
now admit, after reading the essay of Nageli on plants, and
the remarks by various authors with respect to animals, more
especially those recently made by Professor Broca, that in
the earlier editions of my Origin of Species I perhaps attri-
buted too much to the action of natural selection, or the sur-
vival of the fittest. I have altered the fifth edition of the
Origin so as to confine my remarks to adaptive changes of
structure ; but I am convinced^ from the light gained during
even the last few years^ that very many structures which now
appear to be useless^ will hereafter be proved to be useful^
and will therefore come within the range of natural selection.
Nevertheless I did not formerly consider sufficiently the exis-
tence of structures which, as far as we can at present judge,
are neither beneficial nor injurious ; and this I believe to be
one of the greatest oversights as yet detected in my work.'

Now it is to be remarked vhat neither in these passages
nor in any of the other less distinct expressions of opinion on
this question, does Darwin ever admit that " specific characters "
—that is, the particular characters which serve to distinguish
one species from another— are ever useless, much less that
"a large proportion of them" are so, as Mr. Romanes makes
him "freely acknowledge." On the other hand, in the passage
which I have italicised he strongly expresses his view that
much of what we suppose to be useless is due to our ignor-
ance ; and as I hold myself that, as regards many of the sup-
posed useless characters, this is the true explanation, it may
be well to give a brief sketch of the progress of knowledge
in transferring characters from the one category to the other'."

It is needless to continue this quotation, because ot course
no one is disputing that an enormous number of specific

* Darwinism, p. 132.

Appendix 11. 317

characters whose utility is unknown are nevertheless useful,
and therefore due to natural selection. In other words,
the question is not — Are there not many useful specific
characters whose utility is unknown? but — Does it follow
from the theory of natural selection that all specific
characters must necessarily be useful ? Well, it appears to
me that without going further than the above passage,
which Mr. Wallace has quoted, we can see clearly enough
what was Darwin's opinion upon the subject. He did not
believe that it followed deductively from his theory that all
specific characters must necessarily be useful; and therefore
he regarded it as a question o{ fad — to be determined
by induction as distinguished from deduction — in what
proportional number of cases they are so. Moreover he
gives it as his more matured opinion, that, '*as far as we can
at present judge ** (i. e. from the present state of observation
upon the subject : if, with Mr. Wallace, his judgement were
a priori, why this qualification?), he had not previously
sufficiently considered the existence of non-adaptive characters
— and this he ended by believing was one of the greatest
oversights as yet detected in his work. To me it has always
seemed that this passage is one of the greatest exhibitions of
candour, combined with solidity of judgement, that is to be
met with even in the writings of Darwin. There is no talk
about any deductive "necessity"; but a perfect readiness to
allow that causes other than natural selection may have been
at work in evoking non-adaptive characters, so that the fifth
edition of the Origin of Species was altered in order to
confine the theory of natural selection to " adaptive changes "
— i.e. to constitute it, as I have said in other words,
"a theory of the origin, or cumulative development, of
adaplalions."

If to this it be said that in the above passage there
is no special mention of species, the quibble would admit
of a threetold reply. In the first place, the quibble in

3i8 Darwin, and after Darwin,

question had never been raised. As already stated, it is
only since the appearance of my own paper on Physiological
Selection that anybody ever thought of drawing a distinction
between species and genera, such that while all specific char-
acters must be held necessarily useful, no such necessity extends
to generic characters. In the second place, that Darwin must
have had specific characters (as well as generic) in his mind
when writing the above passage, is rendered unquestionable
by the fact that many of the instances of inutility adduced by
Nageli and Broca have reference to specific characters.
Lasdy, as shown in the passages previously quoted from the
sixth edition of the Origin of Species^ Darwin attributed the
origin of useless generic characters to useless specific
characters; so that Mr. Wallace really gains nothing by his
remark that specific characters are not specially mentioned
in the present passage.
Once more : —

"Darwin's latest expression of opinion on this question is
interesting, since it shows he was inclined to return to his
earlier view of the general, or universal, utility of specific
characters '."

This " latest expression of opinion," as I shall immediately
prove, shows nothing of the kind — being, in fact, a mere
re-statement of the opinion everywhere and at all times
expressed by Darwin, touching the caution that must be
observed in deciding, with respect to individual cases, whether
an apparently useless specific character is to be regarded as
really useless. Moreover, at no time and in no place did
Darwin entertain any "view of the general, or universal,
utility of specific characters." But the point now is, that if
(as was the case) Darwin "inclined" to depart more and
more from his earlier view of the highly general utility of
specific characters ; and if (as was not the case) he ended by
showing an inclination " to return " to this earlier view ; what
* Darwinism, p. 142.

Appendix II , 319

becomes of the whole of Mr. Wallace's contention against
which this Appendix is directed, namely, that Darwin never
entertained any other view than that of the ^* general, or
universal, utility of specific characters " ?

The " latest expression of opinion " which Mr. Wallace
quotes, occurs in a letter written to Professor Semper in
1878. It is as follows : —

"As our knowledge advances, very slight differences, con-
sidered by systematists as of no importance in structure, are
continually found to be functionally important ; and I have
been especially struck with this fact in the case of plants, to
which my observations have of late years been confined. There-
fore it seems to me rather rash to consider the slight differ-
ences between representative species, for instance those in-
habiting the different islands of the same archipelago, as of
no functional importance, and as not in any way due to natural
selection \"

Now, with regard to this passage it is to be observed, as
already remarked, that it refers to the formation of final
judgements touching/^r//<f«/^r cases : there is nothing to show
that the writer is contemplating general principles, or advo-
cating on deductive grounds the dogma that specific char-
acters must be necessarily and universally adaptive characters.
Therefore, what he here says is neither more nor less than
I have said. For I have always held that it would be " rather
rash *' to conclude that any given cases of apparent inutility
are certainly cases of real inutility, merely on the ground that
utility is not perceived. But this is clearly quite a distinct
matter from resisting the a priori generalization that all cases
of apparent inutility must certainly be cases of real utility.
And, I maintain, in every part of his wiitings, without any
exception, where Darwin alludes to this matter of general
principle, it is in terms which directly contradict the de-
duction in question. As the whole of this Appendix has ^

' Life and Letters, vol. iii. p. i6i .

320 Darwin, and after Darwin,

been directed to proving that such is the case, it will now,
I think, be sufficient to supply but one further quotation, in
order to show that the above "latest expression of opinion,"
far from indicating that in his later years Darwin "inclined "
to Mr. Wallace's views upon this matter, is quite compatible
with a distinct " expression of opinion " to the contrary, in
a letter written less than six years before his death.

" In my opinion the greatest error which I have committed^
has been not allowing sufficient weight to the direct action of
the environment, i.e. food, climate, &c., independently of natural
selection. Modifications thus caused, which are neither of
advantage nor disadvantage to the modified organisms, would
be especially favoured, as I can now see chiefly through
your observations, by isolation in a small area, where only
a few individuals lived under nearly uniform conditions^"

I will now proceed to quote further passages from
Darwin's works, which appear to have escaped the notice of
Mr. Wallace, inasmuch as they admit of no doubt regarding
the allusions being to specific characters.

" We may easily err in attributing importance to characters,
and in believing that they have been developed through natural
selection. We must by no means overlook the effects of the
definite action of changed conditions of life, — of so-called
spontaneous variations, which seem to depend in a quite
subordinate degree on the nature of the conditions, — of the
tendency to reversion to long-lost characters, — of the complex
laws of growth, such as of correlation ^ compensation, of
pressure of one part on another, &c., and finally of sexual
selection, by which characters of use to one sex are often
gained and then transmitted more or less perfectly to the

* Life and Letters, \o\. iii. p. 158.

^ It must be observed that Darwin uses this word, not as Mr. Wallace
always uses it (viz. as if correlation can only be with regard to adaf>tive
characters;, but in the wider sense that any change in one part of an
organism — whether or not it happens to be an adaptive change — is apt
to induce changes in other pans.

Appendix II. 321

other sex, though of no use to this sex. But structures thus
indirectly gained, although at first of no advantage to a species^
may subsequently have been taken advantage of by its modified
descendants, under new conditions of life and newly acquired
habits V»

It appeared — and still appears — tome, that where so many
causes are expressly assigned as producing useless specific
characters, and that some of them (such as climatic influences
and independent variability) must be highly general in their
action, I was justified in representing it as Darwin's opinion
that "a large proportional number of specific characters"
are useless to the species presenting them, although after-
wards they may sometimes become of use to genera, families,
&c. Moreover, this passage goes on to point out that
specific characters which at first sight appear to be obviously
useful, are sometimes found by fuller knowledge to be really
useless — a consideration which is the exact inverse of the
argument from ignorance as used by Mr. Wallace, and
serves still further to show that in Darwin's opinion utility is
by no means an invariable, still less a *' necessary," mark of
specific character. The following are some of the instances
which he gives.

" The sutures in the skulls of young mammals have been ad-
vanced as a beautiful adaptation for aiding parturition, and no
doubt they may facilitate, or be indispensable for this act ;
but as sutures occur in the skulls of young birds and reptiles,
which have only to escape from a broken ^gg^ we may infer
that this structure has arisen from the laws of growth^ and
has been taken advantage of in the parturition of the higher
animals ^"

" The naked skin on the head of a vulture is generally con-
sidered as a direct adaptation for wallowing in putridity;
and so it may be, or it may possibly be due to the direct
action of the putrid matter ; but we should be very cautious

* Origin of Species, pp. 157-8. =* Ibid.

II. Y

322 Darwin^ and after Darwin,

in drawing any such inference [i.e. as to utility] when we see
the skin on the head of the clean-feeding male Turkey is
likewise naked V*

Similarly, in the Descent of Man it is said : —

" Variations of the same general nature have often been taken
advantage of and accumulated through sexual selection in re-
lation to the propagation of the species, and through natural
selection in relation to the general purposes of life. Hence,
secondary sexual characters^ when equally transmitted to both
sexes, can be distinguished from ordinary specific characters,,
only by the light of analogy. The modifications acquired
through sexual selection are often so strongly pronounced
that the two sexes have frequently been ranked as distinct
species, or even as distinct genera ^"

As Mr. Wallace does not recognize sexual selection, he
incurs the burden of proving utility (in the life-preserving
sense) in all these ** frequently " occurring cases where there
are such '* strongly pronounced modifications," and we have
already seen in the text his manner of dealing with this
burden. But the point here is, that whether or not we
accept the theory of sexual selection, we must accept
it as Darwin's opinion — first, that in their beginnings, as
specific characters, these sexual modifications were often
of a merely '^general nature" (or without reference to
utility even in the Hfe-embellishing sense), and only after-
wards "have often been taken advantage of and accumu-
lated through sexual selection**: and, secondly, that "we
know they have been acquired in some instances at the
cost not only of inconvenience, but of exposure to actual
dangers '/'

We may now pass on to some further, and even stronger,
expressions of opinion with regard to the frequent inutihly of
specific characters.

* Origin of Species, pp. 157-8.

• Descent of Man, p. 615. " Ibid,

Appendix II. 323

** I have made these remarks only to show that, if we are un-
able to account for the characteristic differences of our several
domestic breeds, which nevertheless are generally admitted to
have arisen through ordinary generation from one or a few
parent stocks, we ought not to lay too much stress on our
ignorance of the precise cause [i.e. whether natural selection
or some other cause] of the slight analogous differences between
true species. ... I fully admit that many structures are now
of no use to their possessors, and may never have been of
any use to their progenitors ; but this does not prove that
they were formed solely for beauty or variety. No doubt the
definite action of changed conditions, and the various causes
of modification, lately specified, have all produced an effect,
probably a great effect^ independently of any advantage thus

gained. It is scarcely possible to decide how much

allowance ought to be made for such causes of change, as
the definite action of external conditions, so-called spontaneous
variations, and the complex laws of growth ; but, with these
important exceptions^ we may conclude that the structure of
every living creature either now is, or formerly was, of some
direct or indirect use to its possessor V

Here again, if we remember how "important" these
" exceptions " are, I cannot understand any one doubting
Darwin's opinion to have been that a large proportional
number of specific characters are useless. For that it is
" species " which he here has mainly in his mind is evident
from what he says when again alluding to the subject in
his " Summary of the Chapter " — namely, " In many other
cases [i.e. in cases where natural selection has not been
concerned] modifications are probably the direct result of
the laws of variation or of growth, independently of any
good having been thus gained." Now, not only do these
"laws" apply as much to species as they do to genera;
"but," the passage goes on to say, "even such structures
have often, we may feel assured, been subsequently taken

* Descent of Man, pp. i59-6o#
Y a

324 Darwin y and after Darwin.

advantage of, and still further modified, for the good of
species under new conditions of life/' Obviously, there-
fore, the inutility in such cases is taken to have been prior
to any utility subsequently acquired; and genera are not
historically prior to the species in which they originate.
Here is another quotation : —

" Thus, as I am inclined to believe, morphological differences,
which we consider as important— such as the arrangement of
the leaves, the divisions of the flower or of the ovarium, the
position of the ovules, Sic.^/irst appeared in matiy cases as
fluctuating va7iations^ which sooner or later became constant
through the nature of the organism and of the surrounding
conditions, as well as through the intercrossing of distinct in-
dividuals, but not through natural selection ; for as these
morphological characters do not affect the welfare of the
species^ any slight deviations in them could not have been
governed or accumulated through this latter agency. It is a
strange result which we thus arrive at, namely, that characters
of slight vital importance to the species^ are the most im-
portant to the systematist ; but, as we shall hereafter see when
we treat of the genetic principle of classification, this is by
no means so paradoxical as it may at first appear V

Clearly the view here expressed is that characters which
are now distinctive of higher taxonomic divisions ** first
appeared" in the parent species of such divisions; for
not only would it be unreasonable to attribute the rise and
preservation of useless characters to " fluctuating variations "
affecting a number of species or genera similarly and simul-
taneously ; but it would be impossible that, if such were the
case, they could be rendered "constant through the nature
of the organism and of the surrounding conditions, as well as
through the intercrossing of distinct individuals V

* Descent of Matty ^. 176.

* The pa-^sage to which these remarks apply is likewise quoted,
in the same Connexion as above, in my paper on Physiological Selection.

Appendix IL 325

Here is another passage to the same geneial effect. In
alluding to the objection from inutility as advanced by
Bronn, Broca, and Nageli, Mr. Darwin says : — " There is
much force in the above objection"; and, after again
pointing out the important possibility in any particular
cases of hidden or former use, and the action of the laws of
growth, he goes on to say, — " In the third place, we have
to allow for the direct and definite action of changed con-
ditions of life, and for so-called spontaneous variations, in
which the nature of the conditions plays quite a sub-
ordinate part \" Elsewhere he says, — '* It appears that I
formerly underrated the frequency and value of these latter
forms of variation as leading to permanent modifications of
structure independently of natural selection *." The *' forms of
variation " to which he here alludes are " variations which
seem to us in our ignorance to arise spontaneously"; and
it is evident that such variations cannot well " arise " in
two or more species of a genus similarly and simultane-
ously, so as independently to lead " to permanent modifica-
tions of structure" in two or more parallel lines. It is
further evident that by " spontaneous variations " Darwin
alludes to extreme cases of spontaneous departure from
the general average of specific characters; and therefore
that lesser or more ordinary departures must be of still
greater '* frequency,"

Again, speaking of the principles of classification,
Darwin writes: —

" We care not how trifling a character may be — let it be the
mere inflection of the angle of the jaw, the manner in which

In criticising that paper in Nature (vol. xxxix. p. 127), Mr. Thiselton
Dyer says of my interpretation of this passage, " the obvions drift of this
does not relate to specific- differences, but to those which are charac-
teristic of family." But in making this remark Mr. Dyer could not
have read the passage with sufficient care to note the points which I have
now explained.

* Origin of Species, p. 171. • Ibid, p. 431.

326 Darwin y and after Darwin,

an insect's wing is folded, whether the skin be covered by
hair or feathers— if it prevail throughout many and different
species, especially those having very different habits of life,
it assumes high value [i.e. for purposes of classification]; for
we can account for its presence in so many forms with such
different habits^ only by inheritance from a common parent.
We may err in this respect in regard to single points of structure,
but when several characters, let them be ever so trifling, concur
througliout a large group of beings having different habits, we
may feel almost sure, on the theory of descent, that these
characters have been inherited from a common ancestor; and
we know that such aggregated characters have especial value
in classification ^"

Now it is evident that this argument for the general
theory of evolution would be destroyed, if Wallace's as-
sumption of utility of specific characters as universal were
to be entertained. And the fact of apparently "trifling*
characters occurring throughout a large group of beings
" having different habits " is proof that they are really trifling,
or without utilitarian significance.

It is needless to multiply these quotations, for it appears
to me that the above are amply sufl[icient to establish
the only point with which we are here concerned, namely,
that Darwin's opinion on the subject of utility in relation
to specific characters was substantially identical with my
own. And this is established, not merely by the literal
meaning of the sundry passages here gathered together
from different parts of his writings ; but likewise, and per-
haps still more, from the tone of thought which pervades
these writings as a whole. It requires no words of mine
to show that the literal meaning of the above quotations
is entirely opposed to Mr. Wallace's view touching the
necessary utility of all specific characters ; but upon the
other point — or the general tone of Mr. Darwin's thought
regarding such topics — it may be well to add two remarks.
» Origin of Species, pp. 373-373-

Appendix IL 327

In the first place, it must be evident that so soon as
we cease to be bound by any a priori deduction as to
natural selection being " the exclusive means of modifica-
tions," it ceases to be a matter of much concern to the theory of
natural selection in what proportion other means of modifi-
cation have been at work — especially when non-adaptive
modifications are concerned, and where these have refer-
ence to merely "specific characters,'* or modifications oi
the most incipient kind, least generally diffused among
organic types, and representing the incidence of causes of
less importance than any others in the process of organic
evolution considered as a whole. Consequently, in the
second place, we find that Darwin nowhere displays any
solicitude touching the proportional number of specific char-
acters that may eventually prove to be due to causes other
than natural selection. He takes a much wider and
deeper view of organic evolution, and, having entirely
emancipated himself from the former conception of
species as the organic units, sees virtually no significance
in specific characters, except in so far as they are also
adaptive characters.

Such, at all events, appears to me the obvious interpretation
of his writings when these are carefully read with a view to
ascertaining his ideas upon "Utilitarian doctrine: how far
true." And I make these remarks because it has been laid
to my charge, that in quoting such passages as the above I
have been putting " a strained interpretation " upon Darwin's
utterances : " such admissions," it is said, " Mr. Romanes
appears to me to treat as if wrung from a hostile witness \"
But, from what has gone before, it ought to be apparent
that I take precisely the opposite view to that here imputed.
Far from deeming these and similar passages as " admissions
wrung from a hostile witness," and far from seeking

* Mr. Thiselton Dyer in Nature^ loc. cit.

328 Darwiriy and after Darwin,

to put any " strained interpretation '* upon them, I believe
that they are but the plain and unequivocal expressions
of an opinion which I have always understood that
Darwin held. And if any one has been led to think other-
wise, I throw back this charge of " strained interpretation,*'
by challenging such a person to adduce a single quotation
from any part of Darwin's works, which can possibly be
held to indicate that he regarded passages like those
above quoted as in any way out of conformity with his
theory of natural selection — or as put forward merely
to "admit the possibility of explanations, to which really,
however, he did not attach much importance." To the
best of my judgement it is only some bias in favour of
Mr. Wallace's views that can lead a naturalist to view in
this way the clear and consistent expression of Darwin's.

That Mr. Wallace himself should be biassed in this matter
might, perhaps, be expected. After rendering the following
very unequivocal passage from the Origin of Species (p. 72) —
" There can be little doubt that the tendency to vary in the
same manner has often been so strong, that all individuals of
the same species have been similarly modified without the aid of
any form of selection" — Mr. Wallace says, "But no proof
whatever is offered of this statement, and it is so entirely
opposed to all we know of the facts of variation as given by
Darwin himself, that the important word ' all ' is probably an
oversight." But, if Mr. Wallace had read the very next
sentence he would have seen that here the important
word "all" could not possibly have been "an oversight."
For the passage continues, — " Or only a third, fifth, or tenth
part of the individuals may have been thus affected, of which
fact several instances could be given. Thus Graba estimates
I hat about one-fifth of the guillemots in the Faroe Islands
consist of a variety so well marked, that it was formerly
ranked as a distinct species under the name of Una
lacrymans." And even if this passage had not been thus

Appendix II, 329

specially concerned with the question of the proportion in
which " individuals of the same species have been similarly
modified without the aid of any form of selection^' the oversight
with respect to " the important word ' all * " would still have
remained an oversight of a recurrent character, as the fol-
lowing additional quotations from other parts of Darwin's
writings may perhaps render apparent.

" There must be some efficient cause for each slight individual
difference, as well as for more strongly marked variations
which occasionally arise ; and if the unknown cause were to
act persistently, it is almost certain that all the individuals
of the species would be similarly modified \"

" The acquisition of a useless part can hardly be said to
raise an organism in the natural scale We are so igno-
rant of the exciting cause of the above specified modifications ;
but if the unknown cause were to act almost uniformly for a
length of time, we may infer that the result would be almost
uniform ; and in this case all the individuals of the species
would be modified in the same manner V

Moreover, when dealing even with such comparatively
slight changes as occur between our domesticated varieties —
and which, a fortiori, are less likely to become " stable "
through the uniform operation of causes other than selec-
tion, seeing that they are not only smaller in amount than
occurs among natural species, but also have had but a
comparatively short time in whicli to accumulate — Darwin
is emphatic in his assertion of the same principles. For
instance, in the twenty-third chapter of the Variation of
Plants and Animals under Domestication, he repeatedly
uses the term " definite action of external conditions," and
begins the chapter by explaining his use of the term
thus : —

"By the term definite action, as used in this chapter, I mean
an action of such a nature that, when many individuals of

* Origin of Species, p. 171. * Ibid. p. 175.

330 Darwin, and after Darwin,

the same variety are exposed during: several generations to
any change in their physical conditions of life, a//, or nearly
ally the individuals are modified in the same manner. A new
sub-variety would thus be produced without the aid of selec-
Hon\*

As an example of the special instances that he gives,
I may quote the following from the same work : —

" Each of the endless variations which we see in the plumage
of our fowls must have had some efficient cause ; and if the
same cause were to act uniformly during a long series of
generations on many individuals, all probably would be modi-
fied in the same manner."

And, as instances of his more general statements in Chapter
XXIII, these may suffice : —

"The direct action of the conditions of life, whether leading
to definite or indefinite results, is a totally distinct consider-

ation from the effects of natural selection The

direct and definite action of changed conditions, in contra-
distinction to the accumulation of indefinite variations, seems
to me so tmj)0?tant that I will give a large additional body
of miscellaneous facts V

Then, after giving these facts, and showing how in the
case of species in a state of nature it is often impossible to
decide how much we are to attribute to natural selection and
how much to the definite action of changed conditions, he
begins his general summary of the chapter thus: —

" There can be no doubt, from the facts given in the early
part of this chapter, that extremely slight changes in the
conditions of life sometimes act in a definite manner on our
already variable domesticated productions [productions, there-
fore, with regard to which unilormity and "stability" of
modification are least likely to arise] ; and, as the action
of changed conditions in causing general or indefinite vari-

* Variation, &c., vol. ii.p. 260. * Ibid, vol.ii. p. 261.

Appendix II. 331

ability is accumulative, so it may be with their definite ac-
tion. Hence it is possible that great and definite modifications
of structure may result from altered conditions acting during
a long series of generations. In some few instances a marked
effect has been produced quickly on nll^ or nearly ally the
individuals which have been exposed to some considerable
change of climate, food, or other circumstance *."

Once more, in order to show that he retained these views
to the end of his life, I may quote a passage from the second
edition of the Descent of Man, which is the latest expression
of his opinion upon these points: —

" Each of the endless diversities in plumage, which we see
in our domesticated birds, is, of course, the result of some de-
finite cause ; and under natural and more uniform conditions,
some one tint, assuming that it was in no way injurious^ would
almost certainly sooner or later prevail. The free-inter-
crossing of the many individuals belonging to the same species
would ultimately tend to make any change of colour thus in-
duced uniform in character. .... Can we believe that the
very slight differences in tints and markings between, for in-
stance, the female black-grouse and red-grouse serve as a
protection ? Are partridges as they are now coloured, better
protected than if they had resembled quails? Do the slight
differences between the females of the common pheasant, the
Japan and golden pheasants, serve as a protection, or might
not their plumage have been interchanged with impunity ?
From what Mr. Wallace has observed of the habits of certain
gallinaceous birds in the East, he thinks that such slight
differences are beneficial. For myself, I will only say, I am
not convinced V

Yet *' convinced " he certainly must have been on merely
a priori grounds, had he countenanced Mr. Wallace's
reasoning from the general theory of natural selection ; and
the fact that he here tails to be convinced even by "what
Mr. Wallace has observed of the habits of certain gallinaceous

* Variation^ &c., vol. ii. p. 280. * Descent of Man, pp. 473-4.

332 Darwin^ and after Darwin,

birds," appears to indicate that he had considered the question
of utility with special reference to Mr. Wallace's opinion.
That opinion was then, as now, the avowed result of a theo-
retical prepossession ; and this prepossession, as the above
quotations sufficiently show, was expressly repudiated by
Darwin.

Lastly, this is not the only occasion on which Darwin
expressly repudiates Mr. Wallace's opinion on the point
in question. For it is notorious that these co-authors of
the theory of natural selection have expressed divergent
opinions concerning the origin by natural selection of the
most general of all specific characters — cross-sterility.
Although allowing that cross- sterility between allied species
may be of adaptive value in " keeping incipient species from
blending," Darwin persistently refused to be influenced by
Wallace's belief that it is due to natural selection; i. e. the
belief on which alone can be founded the " necessary de-
duction " with which we have been throughout concerned.

Note A to Page 57.

I THINK it is desirable here to adduce one or two concrete
illustrations of these abstract principles, in order to show how,
as a matter of fact, the structure of Weismann's theory is
such as to preclude the possibility of its assumptions being
disproved— and this even supposing that the theory is false.

At first sight nothing could seem more conclusive on the
side of Darwinian or Lamarckian principles than are the facts
of hereditary disease, in cases where the disease has unques-
tionably been acquired by the parents. Take, for example,
the case of gout. Here there is no suspicion of any microbe
being concerned, nor is there any question about the fact
of the disease being one which is frequently acquired by
certain habits of life. Now, suppose the case of a man who
in middle age acquires the gout by these habits of life — such
as insufficient exercise, over-sufficient food, and free indulgence
in wine. His son inherits the gouty diathesis, and even though
the boy may have the fear of gout before his eyes, and con-
sequently avoid over-eating and alcoholic drinking, &c., the
disease may overtake him also. Well, the natural explanation
of all this is, that the sins of the fathers descend upon the
children ; that gout acquired may become in the next generation
gout transmitted. But, on the other hand, the school of
Weismann will maintain that the reason why the parent
contracted the gout was because he had a congenital, or
" blastogenetic," tendency towards that disease— a tendency
which may, indeed, have been intensified by his habits of
life, but which, in so far as thus intensified, was not trans-
mitted to his offspring. All that was so transmitted was the

334 Darwin, and after Darwin,

congenital tendency ; and all that is proved by such cases as
those above supposed, where the offspring of gouty parents
become gouty notwithstanding their abstemious habits, is that
in such offspring the congenital tendency is even more pro-
nounced than it was in their parents, and therefore did not
require so much inducement in the way of unguarded living
to bring it out. Now, here again, without waiting to consider
the relative probabilities of these two opposing explanations,
it is enough for the purposes of the illustration to remark
that it is obviously impossible to disprove either by means
of the other, or by any class of facts to which they may
severally appeal.

I will give only one further example to show the elusiveness
of Weismann's theory, and the consequent impossibility of
finding any cases in nature which will satisfy the conditions
of proof which the theory imposes. In one of his papers
Weismann says that if there be any truth in the Lamarckian
doctrine of the transmission of acquired characters, it ought
to follow that the human infant should speak by instinct.
For, ever since man became human he has presumably been
a talking animal: at any rate it is certain that he has been
so for an innumerable number of generations. Therefore, by
this time the faculty of language ought to have been so
deeply impressed upon the psychology of the species, that
there ought to be no need to teach the young child its use
of language; and the fact that there is such need is taken
by Weismann to constitute good evidence in proof of the
non-transmissibility of individually acquired characters. Or,
to quote his own words, "it has never yet been found that
a child could read of itself, although its parents had throughout
their whole lives practised this art. Not even are our children
able to talk of their own accord ; yet not only have their
parents, but, more than that, an infinitely long line of ancestors
have never ceased to drill their brains and to perfect their
organs of speech. . . . From this alone we may be disposed
to doubt whether acquired capabilities in the true sense can
ever be transmitted." Well, in answer to this particular case,
we have first of all to remark that the construction of even
the simplest language is, psychologically considered, a matter

Note A. 335

of such enormous complexity, that there is no real analogy
between it and the phenomena of instinct : therefore the fact
that Lamarckian principles cannot be applied to the case
of language is no evidence that they do not hold good as
regards instinct. Secondly, not only the construction, but
still more the use of language is quite out of analogy with
all the phenomena of instinct ; for, in order to use, or speak,
a language, the mind must already be that of a thinking
agent; and therefore to expect that language should be in-
stinctive is tantamount to expecting that the thought of which
it is the vehicle should be instinctive — i.e. that human parents
should transmit the whole organization of their own intellectual
experiences to their unborn children. Thirdly, even neglecting
these considerations, we have to remember that language has
been itself the product of an immensely long course of evolution;
so that even if it were reasonable to expect that a child
should speak by instinct without instruction, it would be
necessary further to expect that the child should begin by
speaking in some score or two of unknown tongues before
it arrived at the one which alone its parents could under-
stand. Probably these considerations are enough to show
how absurd is the suggestion that Darwinians ought to expect
children to speak by instinct. But, now, although it is for
these reasons preposterous under any theory of evolution to
expect that children should be able to use a fully developed
language without instruction, it is by no means so preposterous
to expect that, if all languages present any one simple set
of features in common, these features might by this time
have grown to be instinctive ; for these simple features, being
common to all languages, must have been constantly and
forcibly impressed upon the structure of human psychology
throughout an innumerable number of sequent generations.
Now, there is only one set of features common to all languages ;
and this comprises the combinations of vowel and consonantal
sounds, which go to constitute what we know as articulate
syllables. And, is it not the case that these particular features,
thus common to all languages, as a matter of fact actually
are instinctive ? Long before a young child is able to under-
stand the meanings of any words, it begins to babble articulate

336 Darwin^ and after Darwin,

syllables ; and I do not know that a more striking fact can
be adduced at the present stage of the Weismann controversy
than is this fact which he has thus himself unconsciously
suggested, namely, that the young of the only talking animal
should be alone in presenting— and in unmistakably pre-
senting—the instinct of articulation. Well, such being the
state of matters as regards this particular case, in the course
of a debate which was held at the Newcastle meeting of the
British Association upon the heredity question, 1 presented
this case as I present it now. And subsequently I was met,
as I expected to be met, by its being said that after all the
faculty of making articulate sounds might have been of con-
genital origin. Seeing of how much importance this faculty
must always have been to the human species, it may very
well have been a faculty which early fell under the sway
of natural selection, and so it may have become congenital.
Now, be it remembered, 1 am only adducing this case in
illustration of the elusiveness of Weismann's theory. First
of all he selects the faculty of articulate speech to argue that
it is a faculty which ought to be instinctive if acquired char-
acters ever do become instinctive ; and so good does he deem
it as a test case between the two theories, that he says Jrom
it alone we should be prepared to accept the doctrine that
acquired characters can never become congenital. Then, when
it is shown that the only element in articulate speech which
possibly could have become congenital, actually has become
congenital, the answer we receive is a direct contradiction
of the previous argument : the faculty originally selected as
representative of an acquired character is now taken as repre-
sentative of a congenital one. By thus playing fast and loose
Hfith whatever facts the followers of Darwin may adduce, the
followers of Weismann bring their own position simply to
this : — All characters which can be shown to be inherited
we assume 10 be congenital, or as we term it, " blastogenetic,"
while all characters which can be shown not to be inherited,
we assume to be acquired, or as we term it, " somatogenetic " —
and this merely on the ground that they have been shown
to be inherited or not inherited as the case may be. Now,
there need be no objection to such assumptions, provided

Note B, 337

they are recognized as assumptions ; but so long as the very
question in debate has reference to their validity as assumptions,
it is closely illogical to adduce them as arguments. And this
is the only point with which we are at present concerned.

Note B to Page 89.

In answer to this illustration as previously adduced by me,
Mr. Poulton has objected that the benefit arising from the
peculiar mode of stinging in question is a benefit conferred,
not on the insect which stings, but upon its progeny. The
point of the illustration however has no reference to the
maternal instinct (which here, as elsewhere, I doubt not is
due to natural selection) ; it has reference only to the particular
instinct of selective stinging, which here ministers to the pur-
poses of the other and more general instinct of rearing progeny.
Given then the maternal instinct of stinging prey for the use
of progeny, the question is— What first determined the ancestors
of the Sphex to sting their prey only in nine particular points ?
Darwin's answer to this question is as follows : —

" I have been thinking about Pompilius and its allies. Please
take the trouble to read on perforation of the corolla by Bees, p. 425
of my * Cross-fertilization,' to end of chapter. Bees show so much
intelligence in their acts, that it seems not improbable to me that the
progenitors of Pompilius originally stung caterpillars and spiders, &c.*
in any part of their bodies, and then observed by their intelligence
that if they stung them in one particular place, as between certain
segments on the lower side, their prey was at once paralyzed. It
does not seem to me at all incredible that this action should then
become instinctive, i. e. memory transmitted from one generation
to another. It does not seem necessary to suppose that when
Pompilius stung its prey in the ganglion it intended or knew that
their prey would keep long alive. The development of the larvae
may have been subsequently modified in relation to their half-dead,
instead of wholly dead prey ; supposing that the prey was at first
quite killed, which would have required much stinging. Turn this
over in your mind," &c.

11. Z •

338 Darwin, and after Darwin,

Weismann, on the other hand, can only suppose that this
intensely specialized instinct had its origin in fortuitous varia-
tions in the psychology of the species. But, neglecting the
consideration that, in order to become fixed as an instinct
by natural selection, the particular variation required must
have occurred in many difterent individuals, not only in the
first, but also in the sequent generations, the chances against
its occurring only once, or in but one single individual case, are
many thousands if not millions to one.

INDEX

Acceleration and retardation, i6.
Acquired characters, heredity of,

39' '03,133. ^ ^

Adaptation, 7, 13, 55, 62, 67, 71,
I59> 165; of species and of
specific characters, 166.

Allen, Mr., reterred to, 209.

All-sufficiency of Natural Selection^
referred to, 65, 95.

Alone with the Hairy Ainu, re-
ferred to, 26.

American and European trees
compared, 201.

American Journal of Science^ re-
ferred to, 273.

American Naturalist, referred to,

35. 58. . ^

Ammonites, species of, 254.

Animal Intelligence, referred to, 93.

Animal Life, referred to, loi.

Animal Life and Intelligence, re-
ferred to, 33, 36.

Apparent Paradox in Mental
Evolution^ referred to, 90.

Appendages of Normandy and
Irish pigs, 188.

Articulation and inheritance, 335.

Artistic faculties of man, 27.

Babington, Prof., referred to, 252.
Bachman, Dr., referred to, 186.
Bailey, Prof, referred to, 127.
Baker, Mr., referred lo, 252.

Balancing of brainless frog, 78.

Ball, Mr. Piatt, referred to, 3.
96 ; quoted, 50.

Bateson, Mr. \V., referred to, 36.

Beddard, Mr. F., referred to,
174.

Bentham, Mr., referred to, 253.

Uiids, diagnostic characters of,
176; of Australia, effect of cli-
mate on, 310 ; influence of food
on, 218.

Blastogenetic, 123, 242, 245, 250.

Blending of adaptations, 67.

Brain, referred to, 80.

Broca, Prof., referred to, 64, 67,
174, 318.

Bronn, Prof., referred to, 174.

Brooks, Prof., referred to, 14.

BROWN-SiQUARD,relerredto, 104,
122, 142; quoted, 104.

Buckley, Mr., referred to, 147.

BUCKMAN, Prof. James, referred
to, 125.

BucKMAN, Prof. S. S., referred to,
24.

Butler, Mr. A. G., referred to,

2 54-
BiT'iLER, Mr. Samuel, referred to,

>^7-
Butt rfly, seasonal changes of, 210;
influence of food on, 217.

C.

Carnivora, instincts of, 89.
Carriere, M. L. a., referred to,
133.

%

340

Index.

Cave animals, colour-changes in,

211.

Cave Fauna of North America,
quoted, 211.

Cessation of Selection, 99, 199,
212, 292.

Characters, adaptive and specific,
1 59, 307 ; specific, due to Natural
Selection, 171.

Charadriidae, Geograph ical Distri-
bution of the Family^ quoted,

173.
Chimpanzee, counting of, 31.
Climate, influence of, on plants,

300 ; on animals, 209.
Co-adaptation, 64.
Cjckerell, Prof., referred to,

218.
Colour, 269.
Colour-changes in butterflies, 210.

in cave animals, 211.
Colours of Animals, referred to.

Congenital, as opposed to acquired
characters, 134.

Constancy of characters not neces-
sarily due to Natural Selection,
186.

Conteviporary Review, referred to,
60, 65, 95.

Continuity of germ-plasm, 44, 61,
135; absolute and relative, 134,

155-
Contributions to the Theory of

Natural Selection, referred to, 2 ;

quoted, 180.
Cope, Prof, referred to, 14, 15,

20, 63, 256 ; quoted, 16.
Correlation, 171, 184, 211, 222,

268.
Costa, M., quoted, 217.
Cunningham, Mr. J. T., quoted,

103; referred to, 95, 122.

D.

Dall, Prof, referred to, 14.

Darwin, Charles, referred to,
1-13, 20-22, 25, 44, 45, 51-53,
56, 66, 67, 74, 87, 88, 93, 95,
96-100, 149, 159, 160, 167, 173,
174, 181-183, 187-191, 193.

195, 198, 200-203, ai3-ai6,
218, 219, 226, 256, 261-265,
268, 271, 277, 283, 287, 291,
305-307» 3 '3-33 2, 337; quoted,
ii> 53> 66, 96, 181, 182, 186-
191, 193, 195, 201, 202, 213-
215, 261, 262, 265, 313-316,
319-322, 324-326, 328-331,

337-
Darwin et ses Pricurseurs Fran-

fuis, referred to, 234.
Danvinian Theory of the Origin

of Species, quoted, 254.
Daiwinisni, quoted, 22, 27, 67,

i8r, 182, 186, 189-191, 221,

222, 235, 236, 252, 253, 269,

270* 273, 313, 316; referred

to, 7, 12, 15, 20, 70,
De Candolle, Prof, referred to,

206.
Deep-sea faunas, 212.
Delbceuf, referred to, 224.
Descent of Man, quoted, 25, 322-

•324, 331.

Development of the Hard Parts oj
the Mammalia, referred to, 14.

De Vries, Prof., referred to, 122,
174.

Diai;nostic charactersof birds, 1 76 ;
Marsupials, 178.

Divergent Evolution through
Cumulative Segregation, c^oXt^,
224.

Dixon, Mr. Charles, referred to,
174; quoted, 177, 22.:;.

Doctrijte of Descent and Darwin-
ism, quoted, 2'^o.

Dogs, scratching, reflex of, 80;
shaking off water, 84 ; trans-
plantation of ovaries, 143.

DORFMEISTER, Dr., referred to,
211.

Ducks, use-inheritance in, 96;
losing true plumage, 187.

DUPUY, Dr., referred to, 105.

Dyer, Mr. Thistleton, quoted.
325,337.

E.

Effect of External Influences upon
Development, referred to, 66,95.

Index,

341

Effects of Use and Disuse, quoted,

50.

EiMER, Prof., referred to, 14, 174,
217.

Entomological Society, Trans, of,
quoted, 211 ; referred to, 217.

Epilepsy of guinea-pigs, 104,

Essays on Heredity, quoted, 56,
91, 97, 107, 152; referred to,
12, 36,65, 105, no.

Eudes-Deslongchamps, M., re-
ferred to, 188.

European and American trees,
compared, 201.

Everest, Rev. E., quoted, 213.

Evolution without Natural Selec-
tion, quoted, 127-

Examination of Weismannism,
referred to, 39-42, 44, 100, 122,
123, 134, 136, 138-140, 156.

Experiments in Pangenesis, re-
ferred to, 145.

Fabre, M., referred to, 88.

Factors of organic evolution :
Natural Selection, 2, 5, 6 ; use-
inheritance, 3, II.

Factors of Organic Evolution, re-
ferred to, 8.

Faculties and organs, 39.

Fertility, 229.

Flat-fish, Mr. Cunningham on,
103.

Floral Structures, referred to, 19.

FOCKE, Dr., referred to, 174.

Fonctions du Cerveau, referred to,
109,

Food, influence of, 317.

Foot, of man, 23.

Frog, brainless, balancing of, 78.

G.

Galton, Mr. Francis, referred to,
40-48, 100, 103, 134-139, I45>
146,152,154,156,300,303-305;
quoted, 46, 100.

Gangrene, effects of, 54, 105.

Gardener's Chronicle, quoted, 127.

Gartner, Dr., referred to, 206.

Geddes, Prof., referred to, 15, 30,
174-

Gemmnles, 47,145, i55-
Genera and species, 261.
Germ-plasm and Stirp, 40; and

pangenesis, 42 ; isolation of, 137;

stability of, 243.
Germ-plasm, referred to, 128.
GlARD, Prof., referred to, 14, 174.
Giraffe, co-adaptation in, 64.
GoLTZ, Prot, referred to, 80, 84.
Gould, Mr., referred to, 210.
Graft-hybridization, 143.
Growth, laws of, 333, 326, 248,

270, 321.
Guinea-pigs, epilepsy of, 104.
GULICK, Mr. , referred to, 1 74, 259,

260, 271 ; quoted, 224, 273.
Gute und schlechte Arten, quoted,

203.

H.
Habit, henditary, 87.
Habit and Intelligence, quoted, 335.
Hand, of man, 24.
Handbook of British Flora, referred

to, 252.
Haycraft, Prof., referred to, 80.
Heapk, Mr. Walter, referred to,i47.
Henslow, Prof George, referred

to, 18-20, 127-132, 174, 208;

quoted, 19, 130, 131.
Heredity, problems of, 39.
Hering, Prof., referred to, 87.
Hewitt, Mr., referred to, 187.
Hill, Prof. Leonard, quoted, 132.
Haeckel, Prof., referred to, 174,

260, 282.
Hoffmann, Dr., referred to, 123,

280.
Horse, callosities of, 265.
Huxley, Prof. T. H., referred to,

167-170, 185, 256, 275, 283,

307-312; quoted, 307-309.
Huxleyan doctrine of species, 167.
Hyatt, Prof., referred to, 14, 15.
Hymenoptera, social, 93.

Inadequacy of Natural Selection,

refeired to, 65, 95.
Inconsistencies of Utilitarianism as

the Exclusive Theory of Organic

Evolution, quoted, 373.

342

Index.

Indifferent characters, 171, 185,

208, 247.
Insects, instincts of, gr.
Instability of useless characters,

186.
Instinct and hereditary habit, 87;

of Sphex, 88 ; of carnivora, 89 ;

of man, 89; Prof. Weismann's

views on, 90 ; of insects, 91.
Intercrossing, 67-71.
Isolation, 223 tf/jtf^.

J.
Jordan, Dr., referred to, 206,252.

K.

Karyokinesis, 140.

Kerner, Prof., referred to, 174,

202-206, 231, 239, 260, 282;

quoted, 203.
Koch, Dr., referred to, 217.
KoLLlKER, Prof., referred to, 174.

Lamarck, referred to, 9-15.
Lamarckism, g, 61, 113.
Landor, a. H. Savage, referred to,

26.
Language and Weismannism, 334.
Lankester, Prof. Ray, quoted,

245, 299 ; referred to, 305.
Lesage, M., referred to, 126.
Life and Letters of Charles Darwin J

quoted, 319, 320 ; referred to, 11.
Luciani, referred to, 109.

M.

Making of Flowers, referred to, 19.

Manual of British Botany, re-
ferred to, 252.

Manual of Dental Anatomy, figure
from, 267.

Marsupials, diagnostic characters
of, ip.

Materials for the Study of Varia-
tion, referred to, 36.

Meehan, Mr., referred to, 201.

Meldola, Prof., referred to, 68.

Mental Evolution in Animals, re-
ferred to, 25, 88, 89, 9a.

On Truth, referred to, 317.
Orang-utan, teeth of, 267.
Mental Evolution in Man, referred

to, 31.
Merrifield, Mr., referred to, 211.
Mije, mutilation of tails of, '48.
MlVART, Prof. St. George, referred

to, 4, 174, 217.
Monstrosity, in turkeys, 181 ; in

cattle, 196.
Morgan, Prof. Lloyd, referred

to, 33, 36, I74» 271, 300 305;

quoted, 300, 303.
Moseley, Prof., referred to, 26.
Murphy, Mr. J. J., referred to,

224.
Mutilations, inheritance of, 53, 148.

N.

Nageli, Prof., referred to, 174,

206, 318.
Naked skin of man, 25.
Nathusius, referred to, 188.
Natural Selection, range of, 3, 5,

51, 62, 92 ; a theory of species,

1 6 1 , 1 69 ; and cave animals, 211;

and Porto Santo rabbits, 21 a
Natural Selection and Tropical

Nature, quoted, 23.
Natural Science, quoted, 104.
Wa/Mr^, quoted, 132, 223, 24=,, 99,

325 ; referred to, 68, 98, 218.
Neci-Darwinian school, 10, 61.
Neo-Lamarckian school,i3, 62, 63.
Ntuer Beitrag zum geologischen

Beweis der Darwin schen

Theorie, quoted, 2.A4.
Neuter Lnsects and Darwinism,

referred to, 95.
Neuter Insects a}td Lamarckism,

referred to, 95.
Neuters of hymenopterous insects,

92.
Newman, Cardinal, referred to, 20.
Niata cattle, 191.

O.

Obersteiner, Dr., referred to,

105, 106.
Oesierreichischemedicinischejahr-

biicher, referred to, 105.

Index.

343

Organic Evolution^ referred to,

217.
Origin of the Fittest, quoted, 16;

referred to, 14.
Origine des Plantes Domestiques,

dimontrie par la culture du

Kadis sauvagCy referred to,. 123.
Origin of Sex, referred to, 17.
Origin of Species, Q^oXxA, 3, 4, 181,

1S2, 186, 188,190,261,262, 265,

321,322,325,326,329; referred

to, 67, 159, 227, 286.
OsBOftN, Prof., referred to, 14, 58,

63.
Owen, Sir Richard, referred to,

191.
Oxen, skulls of, compared, 193.
Oysters, change of, 317.

P.

Packard, Prof., referred to, 14,

213.
Pangenesis, ii, 42.
Panmixia, 97, 212, 391.
Parsimony, law of, 51.
Parsnips, variation of, 125.
Pasco E, Mr., referred to, 174;

quoted. 254.
Perkier, Prof., referred to, 14,

93 9.'5-

Peter, Dr., referred to, 206.

Pfeffer, Herr, referred to, 15.

Ffliigers Archiv, referred to, 80.

Philosophical Transactions, re-
ferred to, 103.

Physiological Selection, referred to,
187, 307, 313, 324; quoted, 188,
308.

PiCKARD Cambridge, Rev. O.,
quoted, 221.

Pig, old Irish, 188.

Plants, influence of climate on,
122-207.

Porto Santo rabbits, 314.

PouLTON, E. B., referred to, 36,

217- 337-
Presidential Address to the Bristol

Naturalists Society y\2>gi^<{\iiOteAf

300, 303-
I Proceedings of the Royal Society,

referred to, 145, 147; quoted,

307.

Protective resemblance, 73.
Protrusion of eyeball, in epileptic
guinea-pigs, iii.

QuATREFAGES, M., referred to,

234-

R.

Rabbits, and use-inheritance, 96;
transplantation of ovaries, 143 ;
Porto Santo, 214.

Radish, variation of, 123.

Rats, scratching, reflex of, 81.

Maupen und Schmetterlinge der
Wetterau, referred to, 217.

Reflex action and use-inheritance,
64-87.

Rejoinder to Prof Weismann^ re-
ferred to, 95.

Reversal of selection, loi, 292.

Fevue Gdnirale de Botanie, referred
to, 126.

Richardson, referred to, 188.

Roux, Prof, referred to, 298.

Rudiments, 294.

Ryder, Prof., referred to, 14.

S.

Sachs, Prof., referred to, 15, 174.
"Sally," counting of, 31.
Sauermann, Dr., referred to, 218.
SCHAFER, Prof., referred to, 145.
Schmetterlinge des Siidivestlichen

Deutschlands, referred to, 217,
Schmidt, Dr. Oscar, quoted, 260.
Schools of Evolutionists, i3-Jo.
Scott, Prof., referred to, 63.
Scratching, reflex, in dogs, 80 ; in

rats, 81.
Seasonal changes of butterflies,

210.
Seebohm, Mr. Henry, quoted,

173 ; referred to, 174.
Selection, cessation of, 99, 393;

reversal of, loi, 292.

• sexual, 219 ^/ seq.

Selective value, 73.
Self-adaptation, 18.
Semper, Prof. Karl, referred to»

lOI.

Sexual selection, %\^et seq.

344

Index,

Sole, pigment of, 104,
Somatogcnetic and somatoplasm,

133,137,155,343-249-
Some Laws of Heredity y referred

to, 34.
Species, stress laid on origin of,

159; necessarily due to natural

selection, 168.

definitions of, 229.

Si-RNCER, Herbert, referred to, 8,

64-68, 95.
Sphex, instincts of, 88, 337.
Stebbing, Rev. T. R., quoted, 35.
Sterility, 8.

Stirp'and germ-plasm, 40, 47, 138.
Struggle for Existence between the

parts of an Organism^ referred

to, 299.

T.

T%eory of Heredity, referred to,
40»47» »37, 154; quoted, 46, 47.

Thomas, Mr. Oldfield, referred to,
178.

Thomson, J. A., referred to, 15.

Todd, J. E., referred to, 35.

Tomes, Mr., referred to, 267.

Transfusion of blood in rabbits,

145.
Transplantation of ovaries in

rabbits, 143, 147.
Trees, comparison of European

and American, 201.
Turkey, tuft of hair of, 181 ; losing

metallic tints, 186.

Use-inheritance, 3, 49, 77,95, 151.

Utility, law of, 8, 20, 1 59 ; uni-
versality of, 166; of specific
characters, 172; <rf specific
characters in birds, 1 76 ; of
specific characters in Mammals,
178.

Variation of Animals and Plants
under Domestiea^ioH, qaotedf 3,

4, 53, ^«, 9^, 187, 189, 191,

193, 195, 213-216, 330, 331.
Varieties, climatic, 238.
Vestigial characters, 171, 184, 261,

294.
Vines, Prof, referred to, 297.
Vitality, plumes of birds due to

surplus, 270, 25.
Voice, of man, 25.

W.

Wagner, Moritz, referred to, 217,
Wallace, Mr. A. R., referred to,
2, 6, 9, II, 15, 20-35, 50,66-
70, 167, 169, 173-175, 180-198,
310, 218-227,235-237, 252,256,
258, 263-278, 285, 313-323,
328, 331, 333; quoted, 22-24,
27, 67, 180-182, 185, 186, igo,
191, 221-223, 235, 236, 269,

273, .^13-

Wallacean doctrine of species, 167,
169.

Weismann, Prof, referred to, 3,
7, 9, 12, 13, 39-60, 65, 66. 90-
105, 112, 128, 134-142, 148,
149, 151, 152, 155, 156, 173,
241, 243, 244, 246, 279, 280,
291, 294, 297, 298, 300, 311,
338; quoted, 56, 91, 97, 152,
343, 244, 297.

Weismannism, diagram of con-
stituent theories, 43, 136; elu-
siveness of, 334.

Weismannism once more, referred
to, 66, 95.

Welry, Hon. Lady, referred to,
90.

Westphal, Prof., referred to, 105,
107.

Withdrawal of foot by reflex action,

75-
WWrtenberger, Dr., referred to,

354.

Yarrell, Mr., referred to, 186.

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