The Excitable Cortex of the Chiinpauzee, Orang-Utan, and Goiilhi 195 



animal climbs about cage and runs about the room. Ri<;ht knee-jerk ia 

 the more brisk. 



July 20. — l^ight knee-jerk exaggerated as compared with left, but 

 as the animal's free movements are examined when playing with other 

 animals and in iroinc; about cajje and room, there is no clear evidence to 

 inspection of abnormality in the leg movements. The bar is grasped by 



&c-iif> 



5tK. 



ntk. 



Fig. 23. — Outlines ( x3 nat. size) of cross-sections of the spinal cord, 

 showing the degenerations following ablation of part of the leg 

 area of left hemisphere ; chimpanzee, ablation-experiment 3. 



rio-ht foot deftly, and apparently with power, certainly with enough power 

 to swing the animal from it. 



July 24. — Animal anaesthetised and the central gyri of both hemi- 

 spheres examined systematically by unipolar faradisation. The lesion in 

 leg area, left hemisphere, includes less of that area than was expected ; 

 points 262 and 281, both of them, now yield movement 343. The contrac- 

 tion of the lesion which has occurred seems to have narrowed the lesion 

 laterally and to have displaced it toward mesial edge of hemisphere, so 



