PKEFACE 



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 poAver 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 



