132 ARE THE EFFECTS OF USE INHERITED? 



ance would be most free to develop necessary but 

 seldom-used organs, protective coverings such as 

 shells or skulls, and natural weapons, defences, 

 ornaments, special adaptations, and so forth ; and 

 this would be an advantage for survival would 

 obviously depend on the importance of a structure 

 or faculty in deciding the struggle for existence 

 and reproduction, and not on the total amount 

 of its using or nourishment. If natural selection 

 had on the whole favoured this officious ally and 

 frequent enemy, surely we should find better evi- 

 dence of its existence. 



Without laying undue stress upon the evil 

 effects of use-inheritance, a careful examination 

 of them in detail may at least serve to counter- 

 balance the optimistic a priori arguments for 

 belief in that plausible but unproven factor of 

 evolution. 



The benefits derivable from use-inheritance are 

 largely illusory. vThe effects of use, indeed, are 



