62 ARE THE EFFECTS OF USE INHERITED ? 



may be inherited although not fully exercised 

 during many generations." l In four out of twelve 

 breeds the wing-bones had become slightly heavier 

 relatively to the leg-bones. Do not these facts 

 tend to show that the changes in fowls' wings 

 are due to fluctuating variability and selective 

 influences rather than to a general law whereby the 

 effects of disuse are cumulatively inherited ? 



PIGEONS' WINGS. 



Concerning pigeons' wings Darwin says : " As 

 fancy pigeons are generally confined in aviaries 

 of moderate size, and as even when not confined 

 they do not search for their own food, they must 

 during many generations have used their wings 

 incomparably less than the wild rock-pigeon. . . . 

 but when we turn to the wings we find what at 



1 Variation of Animals and Plants under Domestication, i. 284. 



