1932] Poliak: A-ff event Fiber Systems, Primate Cerebral Cortex 145 



the inferior parietal (supramarginal) convolution was slightly dam- 

 aged. The rest of the left hemisphere and the entire opposite hemi- 

 sphere did not show any changes whatever. 



Immediately after the operation the pupil ipsilateral with the dam- 

 aged hemisphere was found to be dilated (or the opposite pupil 

 constricted ) . Although the animal was a. husky one, the operation 

 proved to be a severe shock. It was doubtful whether the monlcey 

 ate and drank during the first few days after the operation. Ten days 

 later the monkey was still dull and shy. There was no difference in 

 the size of the pupils so far as it was possible to ascertain. Three days 

 later the monkey successfully gathered "lice" and dandruff from his 

 companion with both hands, snatching them with his lips. In collecting 

 food, climbing, and like activities, he used both hands. On the fol- 

 lowing day the monl^ey promptly turned his head to the right from 

 which the visual stimuli came. He was constantly occupied in catch- 

 ing the "lice" of his companion, and he did this with interest. One 

 day later he saw to the right as well as to the left, though it was 

 questionable whether he directed both eyes correctly toward the 

 objects. A day later he certainly preferred the pieces of the carrot 

 falling into the left halves of his visual fields. The pieces of food fall- 

 ing into the right halves of his visual fields up to the median sagittal 

 plane he did not consider. The monkey did not even look to the right 

 side, which to him probably appeared "empty." In picking up the 

 morsels he mostly used his left hand ; on other occasions, however, he 

 used both hands. Two days later Dr. H. Kliiver found a homonymous 

 hemianopsia on the right side with a fair degree of certainty. This 

 was established by larger pieces of apple (2-3 cm.) and by smaller 

 pieces (1 cm.) and also by peanuts, placed two at a time on a black 

 cardboard. The monl^ey invariably chose the pieces falling into the 

 left halves of his visual fields. Three days later the monkey again, as 

 several times before, appeared to see to the right also. This was deter- 

 mined, however, by a simple observation of the animal picking the 

 food and moving around in the cage. Two days later the homonymous 

 hemianopsia on the right side was again apparent. The wa\dng of the 

 hand to his right remained unnoticed. When taking a peanut from 

 its shell he held it with bioth hands, tore the pieces of the shell with 

 his teeth, held the nut correctly with his fingers, and carried it with 

 his right hand to the mouth. In general the monkey appeared passive, 

 almost stupid, was constantly terrorized by other companions, though 

 he in no way appeared physically weak. 



