56 ARE THE EFFECTS OF USE INHERITED ? 



best fliers would escape most frequently, or would 

 pine most if kept confined ? On the other hand, 

 birds with lessened powers of flight would not be 

 eliminated as under natural conditions, but would 

 be favoured ; and natural selection, together with 

 artificial selection of the most flourishing birds, 

 would thicken and strengthen the legs to meet 

 increased demands upon them. 



The diminution of the duck's wing is not great 

 even in the birds that "never fl)f," and from 

 this we must deduct the direct effect of disuse on 

 the individual during its lifetime. As Weismann 

 suggests, the inherited portion of the change could 

 only be ascertained by comparing the bones, &c., 

 of wild and tame ducks similarly reared. If 

 individual disuse diminished the weight of the 

 duck's wing-bones by 9 per cent, there would 

 be nothing left to account for. 



I suspect that investigation would reveal ano- 

 malies inconsistent with the theory of use- 



