Darwinism | Page 2

the subject of specific variability; and it will be
found that, throughout the work, I have frequently to appeal to these
diagrams and the facts they illustrate, just as Darwin was accustomed to
appeal to the facts of variation among dogs and pigeons.
I have also made what appears to me an important change in the
arrangement of the subject. Instead of treating first the comparatively
difficult and unfamiliar details of variation, I commence with the
Struggle for Existence, which is really the fundamental phenomenon on
which natural selection depends, while the particular facts which
illustrate it are comparatively familiar and very interesting. It has the
further advantage that, after discussing variation and the effects of
artificial selection, we proceed at once to explain how natural selection
acts.
Among the subjects of novelty or interest discussed in this volume, and
which have important bearings on the theory of natural selection, are:
(1) A proof that all specific characters are (or once have been) either
useful in themselves or correlated with useful characters (Chap. VI); (2)
a proof that natural selection can, in certain cases, increase the sterility
of crosses (Chap. VII); (3) a fuller discussion of the colour relations of

animals, with additional facts and arguments on the origin of sexual
differences of colour (Chaps. VIII-X); (4) an attempted solution of the
difficulty presented by the occurrence of both very simple and very
complex modes of securing the cross-fertilisation of plants (Chap. XI);
(5) some fresh facts and arguments on the wind-carriage of seeds, and
its bearing on the wide dispersal of many arctic and alpine plants (Chap.
XII); (6) some new illustrations of the non-heredity of acquired
characters, and a proof that the effects of use and disuse, even if
inherited, must be overpowered by natural selection (Chap. XIV); and
(7) a new argument as to the nature and origin of the moral and
intellectual faculties of man (Chap. XV).
* * * * *
Although I maintain, and even enforce, my differences from some of
Darwin's views, my whole work tends forcibly to illustrate the
overwhelming importance of Natural Selection over all other agencies
in the production of new species. I thus take up Darwin's earlier
position, from which he somewhat receded in the later editions of his
works, on account of criticisms and objections which I have
endeavoured to show are unsound. Even in rejecting that phase of
sexual selection depending on female choice, I insist on the greater
efficacy of natural selection. This is pre-eminently the Darwinian
doctrine, and I therefore claim for my book the position of being the
advocate of pure Darwinism.
I wish to express my obligation to Mr. Francis Darwin for lending me
some of his father's unused notes, and to many other friends for facts or
information, which have, I believe, been acknowledged either in the
text or footnotes. Mr. James Sime has kindly read over the proofs and
given me many useful suggestions; and I have to thank Professor
Meldola, Mr. Hemsley, and Mr. E.B. Poulton for valuable notes or
corrections in the later chapters in which their special subjects are
touched upon.
GODALMING, March 1889.

CONTENTS

CHAPTER I
WHAT ARE "SPECIES" AND WHAT IS MEANT BY THEIR
"ORIGIN"
Definition of species--Special creation--The early
transmutationists--Scientific opinion before Darwin--The problem
before Darwin--The change of opinion effected by Darwin--The
Darwinian theory--Proposed mode of treatment of the subject

CHAPTER II
THE STRUGGLE FOR EXISTENCE
Its importance--The struggle among plants--Among
animals--Illustrative cases--Succession of trees in forests of
Denmark--The struggle for existence on the Pampas--Increase of
organisms in a geometrical ratio--Examples of rapid increase of
animals--Rapid increase and wide spread of plants--Great fertility not
essential to rapid increase--Struggle between closely allied species
most severe--The ethical aspect of the struggle for existence

CHAPTER III
THE VARIABILITY OF SPECIES IN A STATE OF NATURE
Importance of variability--Popular ideas regarding it--Variability of the
lower animals--The variability of insects--Variation among
lizards--Variation among birds--Diagrams of bird-variation--Number of
varying individuals--Variation in the mammalia--Variation in internal

organs--Variations in the skull--Variations in the habits of
animals--The variability of plants--Species which vary
little--Concluding remarks

CHAPTER IV
VARIATION OF DOMESTICATED ANIMALS AND
CULTIVATED PLANTS
The facts of variation and artificial selection--Proofs of the generality
of variation--Variations of apples and melons--Variations of
flowers--Variations of domestic animals--Domestic
pigeons--Acclimatisation--Circumstances favourable to selection by
man--Conditions favourable to variation--Concluding remarks

CHAPTER V
NATURAL SELECTION BY VARIATION AND SURVIVAL OF
THE FITTEST
Effect of struggle for existence under unchanged conditions--The effect
under change of conditions--Divergence of character--In insects--In
birds--In mammalia--Divergence leads to a maximum of life in each
area--Closely allied species inhabit distinct areas--Adaptation to
conditions at various periods of life--The continued existence of low
forms of life--Extinction of low types among the higher
animals--Circumstances favourable to the origin of new
species--Probable origin of the dippers--The importance of
isolation--On