DARWIN LEARNS A WORD 43 



intelligence. He was a quiet, sedate, and thoughtful little 

 monkey. His gray hair and beard gave him quite a vener- 

 able aspect, and for this reason I called him Darwin. For 

 some reason he was afraid of me, and I gave him but little 

 attention. In an adjacent cage lived the little brown Cebus, 

 called Puck. The cages were only separated by an open 

 wire partition, through which they could easily see and hear 

 each other. For some weeks I visited Puck almost daily, 

 and in response to his sound for food, I supplied him with 

 nuts, bananas, or other food. I never gave him anything 

 to eat unless he asked me for it in his own speech. 



On one occasion my attention was attracted by little 

 Darwin, who was making a strange sound, such as I had 

 never before heard one of his species utter. At first I did 

 not recognize the sound, but finally discovered that it was 

 intended to imitate the sound of the brown monkey, in 

 response to which I always gave him some nice morsel of 

 food. Darwin had observed that when Puck made this 

 sound he w r as always rewarded with something to eat, 

 and his own evident motive was to secure a like reward. 

 After this I gave him a bit of food in acknowledgment of 

 his efforts. From day to day he improved in making the 

 sound, until at length it could scarcely be detected from 

 that made by Puck. This was accomplished within a period 

 of less than six weeks from the time of my first visit. In 

 this instance, at least, I have witnessed one step taken by 

 a monkey, in learning the speech of another. This was 

 doubly interesting to me in view of the fact that I had long 

 believed, and had announced the belief, that no monkey 

 ever tried to acquire the sounds made by one of another 



