x SOME EXPERIMENTAL RESULTS 201 



animals, principally, I think, because they got no definite 

 impression of the thing to be done. The other bolt was 

 pulled out. There was a definite change, which the 

 animal soon learnt was a necessary preliminary to the 

 opening of the box. The cat altogether failed with this 

 trick, trying to draw the bolt out like the other one. 

 Even the chimpanzee failed, though repeatedly shown. 

 The little Rhesus monkey, Jimmy, of whom I shall have 

 to say more, dealt with the difficulty by turning the box 

 over and over, till presently the bolt fell. 1 Afterwards, I 

 kept my foot on the box, and he gradually learnt how to 

 deal with the bolt by constantly experimenting with it. 

 A similar box with an ordinary iron bolt fitted with a 

 catch was placed in a cage with three large Drills. The 

 bolt was drawn several times in their presence, but they 

 were far too wild to be systematically shown. They made 

 no attempt at it, and it was not till two days after that 

 the box was first found open. 



That day, it was opened twice. Three days later it was again 

 found open, and the next day it was opened half a dozen times. 

 The next day I saw it done for the first time. At the first trial 

 two of the three still bit at the box, but the third pulled the bolt. 

 At the second trial a second 2 monkey attacked the bolt, which 

 was now placed with the catch down. He took the handle, 

 raised it out of the catch by an up and down movement, and con- 

 tinuing the same movement, gradually worked it back. Evidently 

 he had learnt to free the bolt from the catch by repeatedly work- 

 ing the handle up and down, and he kept up this movement when 

 there was no need for it. 



The monkeys, when they did learn this trick, learnt it 

 properly. The case was different with Jack and the 

 elephant. In all, I gave Jack about ninety lessons, and at 

 the end I do not think he clearly appreciated what he had 

 to do. The reason probably is that the staples hid the 



1 On the other hand, a little female monkey did it at sight. She had 

 lived in a house before, and must, I think, have had experience with 

 bolts. 



2 I wish I could be quite sure that it was not the same monkey, as it 

 would throw light on the question of imitation ; but the truth is that the 

 three were so much alike and so wild in their movements that it was 

 difficult to tell. Both Mr. Cray thorn and I were under the impression 

 that it was not the same monkey. 



