THE ORIGIN OF SPECIES 43 



the transmission of characters from one generation to 

 another (heredity). Individuals varying in directions 

 giving them an advantage in the struggle for existence 

 are more likely to survive and leave offspring than their 

 fellows, i.e., have a better chance of being '* naturally 

 selected." And the inheritance of such characters, in- 

 creased in amount by further variation, may be supposed 

 in the end to lead to sufficient divergence from the 

 original stock to constitute new species, just as the 

 "breeds" of domesticated animals have been brought 

 into existence by '' artificial selection." 



Until Darwin's work appeared Huxley neither affirmed 

 nor denied the possibility of transmutation of species, 

 and his scientific work on the lines laid down by 

 Johannes Miiller and Von Baer kept him more than 

 occupied, without troubling unduly about the matter. 

 Even the influence of Herbert Spencer, who held 

 evolution to be a logical necessity, had failed to make 

 him adopt positive evolutionary views. Writing long 

 afterwards on this point he says : — 



" I took my stand upon two grounds : — Firstly, that up to 

 that time, the evidence in favour of transmutation was wholly 

 insufficient ; and secondly, that no suggestion respecting the 

 causes of transmutation assumed, which had been made, was in 

 any way adequate to explain the phenomena. Looking back 

 at the state of knowledge at that time, I really do not see that 

 any other conclusion was justifiable " (Darwin's Life and 

 Letters, ii. p. i88). 



In the same place Huxley tells us that the influence 

 of Lyell, 



" was perhaps more potent than any other in keeping alive a 

 sort of pious conviction that evolution, after all, would turn out 

 true. I have recently read afresh the first edition of the 

 Principles of Geology ; and when I consider that this remarkable 



