Characters as Adaptive and Specific. 261 



the utility or non-utility of organic structures should 

 thus depend on the accidents of human knowledge ; 

 but this is the Darwinian faith, and he who doubts the 

 dogma is to be anathema. 



Turning next to the similar distinction which it 

 is sought to draw between species and genera, here 

 it will probably be urged, as I understand it to 

 be urged by Mr. Wallace, that generic characters 

 (and still more characters of families, orders, &c.) refer 

 back to so remote a state of things that utility 

 may have been present at their birth which has 

 disappeared in their maturity. In other words, it 

 is held that all generic characters were originally 

 specific characters ; that as such they were all origin- 

 ally of use ; but that, after having been rendered 

 stable by heredity, many of them may have ceased 

 to be of service to the descendants of those species 

 in which they originated, and whose extinction has 

 now made it impossible to divine what that service 

 may have been. 



Now, in the first place, this is not the interpretation 

 adopted by Darwin. For instance, he expressly 

 contrasts such cases with those of vestigial or " rudi- 

 mentary" structures, pointing out that they differ 

 from vestigial structures in respect of their perma- 

 nence. One quotation will be sufficient to establish 

 the present point. 



"A structure which has been developed through long-con- 

 tinued selection, when it ceases to be of service to a species, 

 generally becomes variable, as we see with rudimentary organs, 

 for it will no longer be regulated by this same power of 

 selection. But when, from the nature of the organism and 

 of the conditions, modifications have been induced which are 



