266 ARCHIVES OF NEUROLOGY AXD PSYCHIATRY 



thrust into the box tor the food. In the postoperative retention tests, 

 the left hand was not used at all. She first lifted the lid with her right 

 hand, then released it and attempted to grasp the food with the same 

 hand, but the lid falling back prevented this. On the first trial, she 

 finally held the lid back with her right hand, inserted her head in the 

 box and took the food in her teeth. On the second trial, she thrust 

 her head against the lid after raising it with the right hand and so held 

 it open while the hand was inserted in the box. The same method was 

 used on the third and fourth trials. On the fifth trial, she attempted 

 to hold up the lid with her left foot and finally succeeded in this after 

 overbalancing twice. In all later trials, she released the lid and allowed 

 it to fall against her right arm as this was thrust into the box. These 



Fig. 3. — The extent of the lesions in animal Xo. J. Reconstructed from 

 camera sketch and serial sections. Practically the whole of both precentral 

 gyri destroyed, including the paracentral gyrus and cortex within the central 

 sulcus. 



various acts were carried out with definite adaptation to the contour 

 of the box and had none of the elements of random pulling and thrust- 

 ing which characterize the initial stages of learning. As in the case of 

 Number 2, there seemed to be an immediate adaptation of movements 

 to opening the box, which had not been employed at any time in the 

 previous practice. 



Extent of Lesions. — The injured areas are shown in Figure 3 and sections in 

 Plate 3. 



Right Hemisphere: The lesion began at the posterior median end of the 

 central fissure and included practically all of the precentral gyrus. On the 

 median surface, all of the cortex above the callosomarginal fissure was destroyed. 

 Practically all of the gyrus within the rolandic fissure was involved. Laterad. 



