472 H. S. 'Jennings. 



plexity. To control animal behavior it is necessary to study 

 animal nature, in much the same way that it is necessary to study 

 human nature in order to control human behavior. It is neces- 

 sary to know the past history of the organisms, and what is going 

 on within them, in order to predict what they will do. He who 

 expects even the lower anmials to behave always in certain snnple 

 invariable ways when acted upon by the various forces of nature 

 has many disappointments in store, when he comes to make a 

 thorough study of the matter. The internal modifying conditions 

 must be made the object of deliberate and extended investigation 

 in lower animals as w^ell as in higher ones, before the study of 

 behavior can be placed on a really scientific basis. 



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