LESION OF DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 501 
On the fourth day the animal was observed for some time with both its eyes free. 
It was able to pick up grains of corn scattered on the floor, to the right, but not to 
the left. The right eye 'was then bandaged. It continued to pick up grains to the 
right, but not to the left; and in running knocked its head on the left side against 
the leg of a table. 
The left eye was then bandaged, and the right freed. It continued to see well to 
the right and keenly watched flies buzzing about on this side. It looked about both 
to right and left, and in picking up grains frequently reached well across the middle 
line towards the left side. Vision to the extreme left however was deficient. 
Similar observations were made on the seventh day. 
On the tenth day, when the left eye was bandaged, the animal was able with only 
a slight turn of the head to pick up grains, &c., towards the left side. 
With the right eye bandaged, vision to the right was clear, but things to the left of 
the middle line were lost. 
On the fourteenth day, with the left eye bandaged, the animal ran about, skilfully 
catching flies with the right hand to the right side, and also to the left with a slight 
turn of the head. It was also seen on this day to take a fly offered it on the left side, 
with its left hand ; appearing a little uncertain as to its exact position. Did not 
knock its head anywhere though passing and repassing objects on the right and left 
constantly. 
On another occasion it was held up facing a wall on which many flies were settled. 
It caught one or two on its left front with its left hand, without turning its head. 
On the seventeenth day it was seen to run about everywhere without once knocking 
its head, passing close to obstacles right and left. It was also seen to catch flies with 
either hand to right and left. 
The right eye was then bandaged. It still continued able to catch flies with the 
left hand. Whether vision was equally distinct to left as right could not be deter¬ 
mined, but it was certainly not blind to the left side as it had been formerly. Four 
months subsequently, vision to the right and left was to all appearance equally good, 
as the animal was able to pick up minute objects to right and left indifferently, and 
without any abnormal turning of the head. It was killed with chloroform nearly five 
months after the second operation. 
Post-mortem examination .—On the left side the grey matter of the convexity of the 
angular gyrus was merely eroded, and the grey matter at the bottom of the sulci was 
uninjured. There was also slight erosion of the ascending parietal convolution, and of 
the upper extremity of the superior temporo-sphenoidal convolution. The occipital 
lobe was intact, as also the rest of the hemisphere (Plate 21, fig. 16). 
On the right side the occipital lobe was entirely gone, having been cut off exactly 
at the parieto-occipital fissure. The ridges of the angular gyrus were also almost 
entirely obliterated, but the grey matter in the depth of the sulci separating it from 
the ascending parietal and superior temporo-sphenoidal convolutions was intact. The 
