88 SUPEK-ORGANIC EVOLUTION 



first advance of psychic action towards another 

 series. . . . 



" The skin, being the part that is more immedi- 

 ately sensible to different kinds of external 

 stimulus, necessarily undergoes a change where 

 the psychic variations take their origin. This 

 mutual connection between the internal and 

 external relations, which constitute intelligence in 

 all its forms, must take its rise in every case from 

 the internal action of things upon the organism." 



For a positivist these ideas imply an acquaint- 

 ance with phylogeny, ontogeny, embryology, and 

 comparative anatomy, which the illustrious philo- 

 sopher had so fully at his command. 



Apropos of this, let us see what E. Haeckel 

 states : " Comparing the embryogenic evolution of 

 the various sense-organs, it is clear that, at the 

 moment of their appearance, they assume the 

 simplest form imaginable ; and only by degrees do 

 they attain their admirable state of perfection, 

 whereby the sense-organs finally acquire the 

 very curious and complicated structure of the 

 organism." 1 



The same author adds : " It is easy to under- 

 stand the extraordinary impression these facts 

 impose upon anyone who wishes to form a just 

 idea of intellectual life. All science will undergo a 



1 E. Haeckel, Anthropogenic, ou evolution humaine, p. 470. 



