MODIFIED HABITS AND INSTINCTS 221 



eliminate the possibility of the offspring learning by imitation 

 or suggestion. He must also exclude the possibility of selection. 

 He must remember that the offspring are probably as docile, as 

 plastic, as adaptable as their parents, or perhaps more so. Moun- 

 taineering mules come to have an extraordinary power of adapting 

 themselves to peculiar exercises, but mule does not inherit from 

 mule ! 



A hen becomes an adept in rearing ducklings : will her own 

 children, put to a similar task, be less fussy than she was at 

 first ? House-martins have learned to build beneath the eaves : 

 has there been any hereditary transmission of this acquired 

 habit, or is it merely "the result of intelligent adaptation through 

 the influence of tradition " ? Have grouse inherited the habit of 

 flying so as to avoid telegraph wires ? Is it indubitably the 

 case that the kittens of a cat " taught to beg for food like a 

 terrier" may spontaneously exhibit the same peculiar habit? 

 These are some of the cases which Lloyd Morgan discusses, and 

 his conclusion is that the evidence for the transmission of acquired 

 habit is insufficient. 



§ 10. As regards Mutilations and the Like 



When we think of the bellicose activities of our ancestors, it 

 seems almost absurd to discuss the question of the transmissi- 

 bility of the results of mutilations, wounds, and other injuries. 

 Moreover, it is well known that dishorning of cattle, docking of 

 horses' tails, curtailing of sheep, cropping of dogs' ears, and 

 similar practices, have been continued for many generations 

 without any known hereditary effect. The circumcision of the 

 children of Jews and Mohammedans has gone on for many cen- 

 turies, but there is no demonstrable structural result. Yet the 

 question is one of possibilities, and there is a huge literature of 

 observations and experiments. 



Few Useful Results. — The net result, it must be confessed, is 

 very disappointing, and the reasons for this are not far to seek. 



