MENTAL LIFE. OF MONKEYS AND APES 103 



It looked very much like imitation of the human act of using 

 the key, and I therefore planned a test to ascertain whether 

 Julius could readily and skillfully use a key or could learn 

 quickly to do so by watching me. 



The first test was made on May 15 with a heavy box whose 

 hinged lid was held securely in position by means of a hasp 

 and a padlock. The key, which was not more than an inch in 

 length, was fastened to a six inch piece of wire so that Julius 

 could not readily lose it. With the animal opposite me, I 

 placed a piece of banana in the box, then closed the lid and 

 snapped the padlock. I next handed Julius the key. He im- 

 mediately laid it on the floor opposite him and began biting the 

 box, rolling it around, and occasionally biting also at the lock 

 and pulling at it. During these activities he had pulled the 

 box toward his cage. Now he suddenly looked up to the posi- 

 tion where the banana had been suspended in the box experi- 

 ment. Evidently the box had suggested to him the banana. 

 For thirty minutes he struggled with the box almost contin- 

 uously, chewing persistently at the hinges, the hasp, or the 

 lock. Then he took the key in his teeth and tried to push it 

 into one of the hinges, then into the crack beneath the lid of 

 the box. 



Subsequently I allowed him to see me use the key repeatedly, 

 and as a result, he came to use it himself now and then on the 

 edge of the box, but he never succeeded in placing it in the 

 lock, and the outcome of the experiment was total failure on 

 the part of the animal to unfasten the lock of his own initiative 

 or to learn to use the key by watching me do so. I did not 

 make any special attempt to teach him to use the key, but 

 merely gave him opportunity to imitate, and it is by no means 

 impossible that he would have succeeded had the key been 

 larger arid had the situation required less accurately coordinated 

 movements. However, it is fair to say that the evidence of 

 the idea of using the key in the lock was unconvincing. My 

 assistant's observation was, perhaps, misleading in so far as it 

 suggested that idea. It may and probably was purely by ac- 

 cident that the animal used the splinter on the padlock. 



