REMARKS ON NATURAL SELECTION. 351 



evolutionists justly dwelt upon as the most interesting 

 consideration in connection with the whole subject — 

 are more noteworthy factors of modification than the 

 factor that an animal, if born fitter for its conditions, 

 will commonly survive longer in the struggle for ex- 

 istence. If the first of these can be explained in such a 

 maimer as to be accepted as true, or highly probable, we 

 have a substantial gain to our knowledge. The second 

 is little — if at all — better than a truism. Granted, 

 if it were not generally the case that those forms are 

 most likely to survive which are best fitted for the 

 conditions of their existence, no adaptation of form to 

 conditions of existence could ever have come about. 

 "The survival of the fittest" therefore, or, perhaps 

 better, " the fertility of the fittest," is thus a sime qua 

 rum for modification. But, as we have just insisted, 

 this does not render " the fertility of the fittest " an 

 especial " means of modification," rather than any other 

 sine qua non for modification. 



But, to look at the matter in another light. Mr. 

 Darwin maintains natural selection to be "the most 

 important but not the exclusive means of modification." 



For " natural selection " substitute the words " sur- 

 vival of the fittest," which we may do with Mr. Darwin's 

 own consent abundantly given. 



To the words "survival of the fittest" add what is 

 elided, but what is, nevertheless, unquestionably as much 

 implied as though it were said openly whenever these 

 words are used, and without which "fittest" haa no 

 force — I mean, " for the conditions of their existence." 



We thus find that when Mr. Darwin says that natural 



