TEST OF MENTAL POWERS 161 



drink from the bottle while he was holding it, but when he 

 let it go, it hung in such a position that they could not get 

 the water out of it at all. At length Aaron solved the 

 problem by climbing up one side of the cage and getting 

 on a level with the bottle ; then he reached across the 

 angle formed by the two sides of the cage and drank. In 

 this position it was no matter to him how much the water 

 ran out ; it could n't touch him. Elisheba watched him 

 until she quite grasped the idea ; then she climbed up in 

 the same manner and slaked her thirst. I scolded the boy 

 for serving them with such cruel tricks ; but it taught me 

 another lesson of value concerning the mental resources 

 of the chimpanzee, for no philosopher could have found a 

 much better scheme to obviate the trouble than did this 

 cunning little sage in the hour of necessity. 



I have never regarded the training of animals as the true 

 measure of their mental powers. The real test is to reduce 

 the animal to his own resources, and see how he will con- 

 duct himself under conditions that present new problems. 

 Animals may be taught to do many things in a mechanical 

 way, and without any motive that relates to the action ; 

 but when they can work out the solution without the aid 

 of man, it is only the faculty of reason that can guide 

 them. 



One thing that Aaron could never figure out was — what 

 became of the chimpanzee that he saw in a mirror. I have 

 seen him hunt for that mysterious ape an hour at a time. 

 He once broke a piece off a mirror I had in trying to find 

 the other fellow, but he never succeeded. I have held the 

 glass firmly before him, while he put his face up close 



