PREFACE 
The present work treats the problem of the Origin of Species 
on the same general lines as were- adopted by Darwin ; but 
from the standpoint reached after nearly thirty years of 
discussion, with an abundance of new facts and the advocacy 
of many new or old theories. 
While not attempting to deal, even in outline, with the 
vast subject of evolution in general, an endeavour has been 
made to give such an account of the theory of Natural Selec¬ 
tion as may enable any intelligent reader to obtain a clear 
conception of Darwin’s work, and to understand something 
of the power and range of his great principle. 
Darwin wrote for a generation which had not accepted 
evolution, and which poured contempt on those who upheld 
the derivation of species from species by any natural law of 
descent. He did his work so well that “ descent with 
modification ” is now universally accepted as the order of 
nature in the organic world ; and the rising generation of 
naturalists can hardly realise the novelty of this idea, or that 
their fathers considered it a scientific heresy to be condemned 
rather than seriously discussed. 
The objections now made to Darwin’s theory apply, solely, 
to the particular means by which the change of species has 
been brought about, not to the fact of that change. The 
objectors seek to minimise the agency of natural selection 
and to subordinate it to laws of variation, of use and disuse, 
of intelligence, and of heredity. These views and objections 
