106 ROBERT M. YERKES 



boxes whose edges had been bound with tin so that it was 

 impossible for the monkey to destroy them. He spent several 

 minutes searching for a starting point on the middle sized box, 

 but finding none, he dragged it under the banana, looked up, 

 mounted the box, but, as previously, did not reach for the bait 

 because it was beyond his reach. He then played with the 

 boxes for several minutes. Finally he worked the two smaller 

 boxes to a position directly under the banana, put the middle 

 sized one on end, mounted it, and looked at the bait, but again 

 abandoned the attempt without reaching. 



During the thirty minutes of observation he made no definite 

 effort to place one box upon another. Three times he mounted 

 one or another of the boxes when it was under the banana or 

 nearly so, but in no case was it possible for him to reach the bait. 



From the above description of this monkey's behavior, it 

 seems fairly certain that with sufficient opportunity, under 

 strong hunger, he would ultimately succeed in obtaining the 

 bait by the use of two or more boxes. For his somewhat abor- 

 tive and never long continued efforts to drag two boxes together 

 or to place the one upon the other clearly enough indicate a 

 tendency which would ultimately yield success. The possibility 

 of imitation is not excluded, for Skirrl had opportunities to see 

 Julius and the experimenter handle the boxes. 



Because of the other work which seemed more important at 

 the time, this experiment was not continued further. The re- 

 sults obtained suggest the desirability of testing thoroughly the 

 ability of monkeys to use objects as only the anthropoid apes 

 and man have heretofore been thought capable of using them. 



Box and Pole Experiment 

 Skirrl was first tested with the box and pole experiment on 

 August 12. As in the case of JuHus, a half banana was placed 

 in the middle of the long box and the attention of the monkey 

 was attracted to the bait by small pieces of carrot placed near 

 each open end. Two poles were placed near the box on the 

 floor of the cage. When admitted to the cage Skirrl went 

 almost directly to the ends of the box, took the pieces of carrot 

 which were in sight, but apparently failed to perceive the bait 

 in the middle of the box. For a while he played with the locks 

 on the box, shoved it about, and amused himself with it, showing 



