276 Darwin, and after Darwin. 



taxonomic divisions, that the theory which accounts 

 for these adaptations accounts also for the forms which 

 present them, i. e. becomes also a theory of the origin 

 of species. This, however, is clearly but an accident of 

 particular cases ; and, therefore, even in them the 

 theory is primarily a theory of adaptations, while it is 

 but secondarily a theory of the species which present 

 them. Or, otherwise stated, the theory is no more a 

 theory of the origin of species than it is of the origin 

 of genera, families, and the rest ; while, on the other 

 hand, it is everywhere a theory of the adaptive modifi- 

 cations whereby each of these taxonomic divisions has 

 been differentiated as such. Yet, sufficiently obvious 

 as the accuracy of this definition must appear to any 

 one who dispassionately considers it, several naturalists 

 of high standing have denounced it in violent terms. 

 I shall therefore have to recur to the subject at some- 

 what greater length hereafter. At present it is enough 

 merely to mention the matter, as furnishing another 

 and a curious illustration of the not infrequent 

 weakness of logical perception on the part of minds 

 well gifted with the faculty of observation. It may be 

 added, however, that the definition in question is in 

 no way hostile to the one which is virtually given by 

 Darwin in the title of his great work. The Origin of 

 Species by means of Natural Selection is beyond 

 doubt the best title that could have been given, 

 because at the time when the work was published the 

 fact, no less than the method, of organic evolution had 

 to be established ; and hence the most important 

 thing to be done at that time was to prove the 

 transmutation of species. But now that this has been 

 done to the satisfaction of naturalists in general, it is, 



