THE THEORY OF ORGANIC EVOLUTION. 427 



Spencer and Wallace, Haeckel and Huxley. (&) 

 He applied the evolution-idea to various sets of facts, 

 such as the expression of the emotions and the de- 

 scent of man, and showed what a powerful organon 

 it was. Here, again, he was greatly aided by his 

 contemporaries, and Spencer's work in this direction 

 is even more important than Darwin's, (c) At the 

 same time as Alfred Kussel Wallace, he elaborated 

 the theory of natural selection, of which there had 

 been a few previous suggestions." * 



(6) Since Darwin secured the general acceptance 

 of the evolution-idea, the attention of evolutionists 

 has been chiefly directed to a discussion and criti- 

 cism of the factors in the evolution-process. Natu- 

 ral Selection working on germinal variations has 

 seemed to some an adequate formula; and this con- 

 sistent Darwinism had been strengthened by a recog- 

 nition of the importance of Isolation (Romanes and 

 Gulick), while Weismann has added the subtle idea 

 of " Germinal Selection." In spite of the growing 

 scepticism as to the transmissibility of functional 

 and environmental modifications, many adhere to 

 the Lamarckian and Buffonian position, that these 

 are of direct importance in evolution. This may or 

 may not be combined with a recognition of the im- 

 portance of Selection. Others, again, following 

 Goethe and Nageli, regard the evolution of organisms 

 as pre-eminently a story of self-differentiating and 

 self-integrating growth, cumulative, selective, defi- 

 nite, and harmonious like crystallisation. Believ- 

 ing in progressive variations in definite directions as 

 opposed to indefinite sports, they find little need to 

 invoke Natural Selection except as pruning the occa- 



* Op. cit. p. 223. 



