160 Inheritance of Acquired Characters 



so on, can not constitute any satisfactory proof in the 

 absence of reliable observation and confirmation of the 

 facts. 



Darwin draws especial attention to the inheritance of 

 characters acquired by domestic animals. "The domes- 

 ticated duck," he remarks, "flies less and walks more than 

 the wild duck and the bones of its anterior and posterior 

 limbs have become respectively diminished and increased 

 in comparison with those of the wild duck. A horse is 

 trained to certain paces and the colt inherits similar con- 

 sensual movements. The domesticated rabbit becomes 

 tame from close confinement ; the dog intelligent from as- 

 sociating with man; the retriever is taught to fetch and 

 carry; and these mental endowments and bodily powers 

 are all inherited." 127 



These examples, one must admit, deserve all considera- 

 tion, especially the first. But one encounters here the ob- 

 jection which can always be raised against such examples : 

 As functional adaptation has a great modifying influence 

 upon the organism, how can we be certain that the greater 

 size of the bones of the legs in the domestic duck really 

 springs from inheritance of acquired characters rather 

 than from the daily exercise of the individual itself? 

 Would not a wild duck if it were obliged to walk during 

 all its life from its coming out of the egg acquire a similar 

 hypertrophy of these bones? Unfortunately we have not 

 exact measurements on this point which alone could de- 

 cide the question whether hypertrophy acquired during 

 the life of an individual could attain the same degree as 

 that which has been observed in the domestic duck. 



Several travellers have remarked that when men have 



127 Darwin : The Variation of Animals and Plants under Vol. II. 

 P. 367. 



