114 ROBERT M. YERKES 



of methods which would be used by the animal in the first few 

 presentations of a situation. It is practically certain that both 

 of these monkeys would have succeeded ultimately in solving 

 the problem of obtaining the food had they been left in the 

 cage with a number of boxes, for Skirrl very early indicated 

 interest in moving the boxes about, and Sobke showed a ten- 

 dency in that direction which perhaps was inhibited partially 

 by his distrust of the experimenter. 



Draw-in Experiment 



For Sobke, as for Julius and Skirrl, the draw-in test was 

 made by putting food on a shelf outside the cage, beyond the 

 reach of the animal, and placing in the cage with the animal 

 one or two sticks long enough to be used for drawing in the bait. 



Sobke was first given this test on July 24. He tried per- 

 sistently to reach the banana with his hand, seized the box 

 which supported the bait, shook it, picked up one or other of 

 the sticks, and chewed at it repeatedly, but not once did he 

 make any move to use a stick to draw the food toward him. 



This experiment was repeated on July 27, 29, 30 and 31, a 

 period of thirty minutes being allowed on each day for obser- 

 vation. At no time did Sobke show any inclination to use 

 either a stick or any other object as a means of reaching the 

 bait. Instead, he confined himself strictly to the use of hands 

 and teeth. 



This test makes it fairly certain that Sobke had no natural 

 tendency to use objects as tools. In so far as he attended to 

 things about the cage or laboratory, it seemed to be rather to 

 play with them in a general way than to use them ideationally 

 or otherwise for definite purposes. 



The definitely negative result of the draw-in experiment ren- 

 dered needless prolonged observation with the box and pole 

 test, whose results are now to be presented. 



Box and Pole Experiment 



The eighty-four inch box, previously used for a similar test 

 with Julius, was presented to Sobke on August 24, the wooden 

 cover having been replaced by a wire one so that the monkey 

 could readily see the bait in the middle of the box. Sobke, 



