92 ARE THE EFFECTS OF USE INHERITED? 



from the lessened use of the wings and the in- 

 creased use of the legs." " Use " is at bottom the 

 determining circumstance in evolution generally/ 

 The trunk of the elephant, the fin of the fish, the 

 wing of the bird, the cunning hand of man and his 

 complicated brain and, in short, all organs and 

 faculties whatsoever can only have been moulded 

 and developed by use by usefulness and by using 

 but not necessarily by use-inheritance, not ne- 

 cessarily by directly inherited effects of use or 

 disuse of parts in the individual. So, too, reduced 

 or rudimentary organs are due to disuse, but it by 

 no means follows that the diminution is caused by 

 any direct tendency to the inheritance of the effects 

 of disuse in the individual. The effects of natural 

 selection are commonly expressible as effects of use 

 and disuse, just as adaptation in nature is expres- 

 sible in the language of teleology. But use-inherit- 

 ance is no more proven by one of these necessary 

 coincidences than special design is by the other. 



