CHAPTER X. 



Characters as Adaptive and Specific 

 {concluded). 



Our subject is not yet exhausted. For it remains 

 to observe the consequences which arise from the 

 dogma of utility as the only raison d'Hre of species, 

 or of specific characters, when this dogma is applied 

 in practice by its own promoters. 



Any definition of "species" — excepting Nos. i, a, 

 and 5, which may here be disregarded — must needs 

 contain some such phrase as the one with which Nos. 3 

 and 4 conclude. This is, that peculiar characters, in 

 order to be recognized as of specific value, must 

 present neither more nor less than "some certain 

 degree of distinctness." If they present more than 

 this degree of distinctness, the form, or forms, in 

 question must be ranked as generic ; while if they 

 present less than this degree of distinctness, they 

 must be regarded as varietal — and this even if 

 they are known to be mutually sterile. What, 

 then, is this certain degree of distinctness.' What 

 are its upper and lower limits.? This question is 

 one that cannot be answered. From the very 

 nature of the case it is impossible to find a 



