FROM LAMARCK TO ST. HILAIRE 241 



wants necessarily bring about parallel "changes in 

 their actions. If the new wants become constant or 

 very lasting, the animals form new habits. ... If 

 new circumstances becoming permanent in a race of 

 animals have given them new habits, there will result 

 the preferred use of such a part and, in certain 

 cases, the total lack of use of such a part as has be- 

 come useless. 



He illustrates his theory in advancing proofs 

 that it is not the organ which gives origin to the 

 habit, but the habit which gives origin to the 

 organ, and points out examples of the effects 

 of use and disuse. He refers all rudimentary 

 structures to disuse, such as the embryonic teeth 

 of the whale-bone whales which had recently 

 been discovered by St. Hilaire, the eyes of the 

 mole and of the Proteus, the blind salamander of 

 the Austrian caves. He is inconsistent with his 

 own theory when he says that the organ of hear- 

 ing has been developed everywhere by the direct 

 action of vibrations of sound. Again, he explains 

 the development of the webbed feet of birds by 

 their being attracted to swamp ground by hun- 

 ger and making efforts to swim by spreading the 

 toes, the skin being thus stretched between them. 



His conception of the initial causal relation of 

 the desires and wants of animals is illustrated in 

 the following paragraphs:^ 



^Histoire Naturelle, 1835, vol. 1, p. 167. 



