134 University of California Puhlications in Anatomy [Vol. 2 



Experiment V-c 



In this experiment the intent was to make several small injuries to 

 the macular portion of the striate area in both hemispheres and to 

 study the number, size, extent, and above all the position of the 

 degenerated zones in both external geniculate bodies. It was hoped 

 that if the cortical injuries were sufficiently small and confined to the 

 striate cortex, and sufficiently isolated from one another, this would be 

 reflected in the size, location, and arrangement of the degenerated 

 zones in the geniculate bodies. Since the arrangement of the cortical 

 injuries could easily be determined this would give, it was expected, 

 enough data to find out whether the ' ' figure ' 'or the ' ' configuration ' ' 

 of the macular cortical lesion was preserved in the macular segments 

 of the lateral geniculate bodies. 



For this purpose the following experiments were performed on a 

 half-grown Macacus rhesus : 



(a) In the left hemisphere three small lesions of about equal size 

 and almost equally distant from each other were made in the macular 

 portion of the striate area, two along the simian sulcus {h and c in 

 1 and 2, fig. 17), and the third along the lower limit of the macular 

 cortex (d in 1 and 2, fig. 17) ; in this same hemisphere a fourth and 

 considerably larger lesion was made in the upper edge of the occipital 

 operculum extending as far back as the occipital pole (a in 1, 2, and 

 ^,%. 17). 



(b) In the right hemisphere one small lesion was made in the upper 

 portion of the occipital operculum (marked with a double cross in 

 3 and 4, fig. 17) ; a second and a more extensive lesion was made in the 

 lower third of the occipital operculum (marked with an asterisk in 

 3 and 4, fig. 17). 



Observation of the visual behavior of the Tuonkey beginning with 

 the fifteenth day after the operation revealed a general disturbance 

 of the vision. Besides that, hemianoptic symptoms to the right 

 were apparent: the monkey never noticed a morsel of food offered 

 from the right side ; but he saw it immediately when it reached the 

 middle sagittal plane, or when it was offered from his left side (he 

 reached for it with his left hand). However, he usually passed the 

 object to the left and also miscalculated the distance. He grasped the 

 object with the hand in a clumsy way, and he climbed slowly, cau- 

 tiously, hesitatingly, in a quasi-ataetic manner. This was understood 



