ISO ARE THE EFFECTS OF USE INHERITED? 



distinguished from other more powerful and de- 

 monstrable factors of evolution. So little does it 

 care to display its powers where they would be 

 easily verifiable as well as useful that practical 

 breeders ignore it. So slight is its independent 

 power that it seems to allow natural selection or 

 sexual selection or artificial selection to modify 

 organisms in sheer defiance of its utmost opposi- 

 tion, just as readily as they modify organisms in 

 other directions with its utmost help. If it 

 partially perpetuates and extends the pecked-out 

 indentations in the motmot's tail feathers, it on the 

 other hand fails to transmit the slightest trace of 

 mutilation in an almost infinite number of 

 ordinary cases, and even where the mutilation is 

 repeated for a hundred generations ; and it 

 apparently repairs rather than transmits the 

 ordinary and oft-repeated losses caused by 

 plucking hair, down and feathers, and the wear 

 and tear of claws, teeth, hoofs and skin. 



