LASH LEY— CEREBRAL FUNCTION 261 



The short time required for opening the boxes in the postoperative 

 retention tests gives clear evidence for some retention of the habits. 

 Much of the delay apparent was due to the weakness and clumsiness 

 of the right hand. With each problem-box the attack in the postopera- 

 tive retention tests was directly on the latches. The methods employed 

 were at first those used before operation, and the movements were 

 definitely adapted to solving the problems, although lacking force and 

 accuracy; for example, efforts were all directed to turning the crank 

 counter-clockwise. 



The weakness of the right arm led to a surprising readjustment on 

 the part of this animal. The operation on the right hemisphere made 

 the left arm weak and spastic during training. In all of the trials of 

 training and preliminary retention tests the left arm was used only as 

 a pro]), and the left hand was not once used in manipulating the latches 

 of any of the boxes. After the second operation, the right hand was 

 much more affected than the left, which had largely recovered, and 

 an almost immediate shift to the left hand in opening all of the boxes 

 occurred. 



Pull Box : Postoperative retention tests. Trial 1 : Fumbled in hole with 

 right hand, removed hand, peered into hole; again inserted right hand and again 

 pulled lever ; twenty-seven seconds. 



Trial 2 : Right hand, fairly accurately, seven seconds. 



Trial 3: He fumbled with right, then inserted left, grasped lever and pulled: 

 seven seconds. 



Trial 4 : He inserted left hand at once ; three seconds. 



Trial 5: Left hand used at once; five seconds. 



The right hand was used only four times in the succeeding forty trials. 



Crank Box: Trial 1: He grasped the crank with his right hand at once 

 and turned counter-clockwise. The crank stuck in the third quadrant. He 

 pushed at it feebly, gave up, returned to the attack from the side of the box 

 and pulled it through final segment ; 160 seconds. 



Trial 2: He grasped the crank with the right hand. Apparently, he was 

 unable to move it. He grasped it with both hands and swung it around ; 

 twenty-five seconds. 



Trials 3, 4 and 5: He used only the right hand and turned with difficulty 

 moving to side of box and exerting direct pull instead of his former transverse- 

 rotary movement. 



Trial 6: He grasped with the left hand and turned counter-clockwise; 

 six seconds. All later trials were made with the left hand only. 



Hasp Box: On the first three days of the postoperative tests, he pulled 

 out the plug and disengaged the hasp promptly with his right hand, but lacked 

 strength to lift the lid. He gave up after a few attempts with his right hand. 



On the fourth day, he drew out the plug and disengaged the hasp with his 

 right hand, then lifted the lid with his left foot. It fell back as he attempted 

 to reach the food. He lifted it again with his left hand, climbed to the edge 

 of the box, bringing his right side against the lid, so holding it up while he 

 grasped the food with his left hand. On the second trial, he lifted with the 

 left hand and held it up with his left hand, inserting his head for the food. In 



