32 APES AND MONKEYS 



the Rhesus. The fact that monkeys generally seem to be 

 attracted by brilliant colors is doubtless due to the readi- 

 ness with which these catch the attention ; but when 

 reduced to a choice between two colors, they do not 

 seem to give preference to brilliant ones. 



A unique but simple experiment was made in order to 

 ascertain whether or not monkeys enumerate. I placed 

 on a small platter one nut and a small piece of apple or 

 carrot cut in the shape of a cube. On another platter 

 were placed two or three such articles of like color and 

 size. Holding the two just out of reach of the monkey, 

 and changing hands from time to time, I observed that he 

 tried to reach the platter containing the greater number, 

 thus indicating that he discerned which contained the 

 greater quantity or number of articles. It was long a 

 matter of doubt as to whether it was by number or by 

 quantity that his choice was controlled. But by taking 

 one piece larger than the others and of different shape, it 

 was ascertained that he appreciated the difference of quan- 

 tity. Then, by taking a platter containing one piece and 

 another platter containing several similar pieces, it was 

 seen that he could distinguish singular from plural. 



Another experiment was to determine to what extent he 

 was able to enumerate. To this end I constructed a small 

 square box and made a hole in one side of it. The box 

 was cushioned inside so that the contents would not rattle. 

 In the box were placed three marbles of the same size and 

 color. The hole was just large enough for the monkey to 

 withdraw his hand with one marble at a time. After let- 

 ting him play with these for a while, putting them into the 



