150 University of California Publications in Anatomy [Vol. 2 



or both hands together. On the next day (last day of observation) the 

 monkey took just the pieces of food lying to his left side, never those 

 to his right. When picking up the morsels he behaved in a peculiar 

 way, different from that of other monl^eys, with a possible exception 

 of a monkey with an isolated damage to tlie macular cortex of both 

 sides (Experiment V-c). Wlien descending to the floor of the cag'e 

 where the pieces of food were scattered he was cautious, hesitating 

 when looking straight forward, as if not recognizing sufficiently 

 rapidly the various objects or morsels which were to his liking: The 

 exclusive choosing of objects falling into the left halves of his visual 

 fields was a well ascertained fact, as was also the preponderant use of 

 his left hand. Only occasionally did he pick up objects with his right 

 hand. In contradistinction to this he used his right hand very well 

 in bringing food to the mouth, although he generally used both hands 

 for this purpose. It was remarkable that even during a prolonged 

 observation (the last day about three hours) the objects to the right 

 were persistently left out of consideration. Another interesting feature 

 was that, though he made no proper circus movements — that is more 

 or less rapid movements around his own axis — when he sometimes 

 slowly explored the rubbish covering the floor of the cage wherein 

 various food particles lay scattered, he seemed to "follow" the func- 

 tioning halves of his visual fields, in this case to the left, in such a way 

 that in the course of one or of several minutes he described one-half 

 or even one complete circle counter-clockwise in direction. A similar 

 movement to the right in a sense opposite to the dial movement was 

 never observed. Further observation shows that when the monkey 

 used both hands, as in exploring the fur of his companion, the right 

 hand was used in a more passive, accessory way. In picking up the 

 ' ' lice ' ' or dandruff he seemed more slow than the animals with normal 

 sight; he gazed every time for a while at the object before he 

 actually "found" it. He seemed to have difficulties either in fixing, 

 or in recognizing and identifying the objects, though this function 

 appeared to be impaired rather in degree than in quality. The same 

 disturbance was apparent when the monkey tried to take one of the 

 peanuts from its shell. When he saw the edible nut he was quasi- 

 puzzled, and then after a few seconds when he realized its meaning, 

 he carried it to his mouth (the other nut, perhaps unseen or unrecog- 

 nized, fell to the floor). The left pupil immediately after deep narcosis 

 and after death appeared somewhat smaller. 



