LESION OF DIFFERENT REGION'S OF THE CEREBRAL HEMISPHERES. 499 
it was sitting with its right side close against the left side of another Monkey which 
was eating an apple. It was looking very eagerly and covetously, and on the apple 
being accidentally dropped by the other, it reached across with its left hand, seized 
the apple, and made off with it. 
On the tenth day it was seen while sitting on the top of a hot-water pipe to reach 
down with its right hand, and pick up a chestnut lying in its cage. 
On the eleventh day it was seen to spring past objects on either side without once 
knocking its head. 
From the thirteenth day onward it was impossible to discover any traces of hemi- 
opia,, as the animal was able to pick up grains of oats, &c., scattered on the floor to 
the right as well as the left, and without making any perceptible motion of its head. 
It seemed to have cpute recovered ; and it remained in excellent health till it was 
killed with chloroform five months after the operation. 
Post-mortem examination .—The left hemisphere was truncated, exposing the upper 
surface of the left side of the cerebellum. The convex aspect of the left hemisphere 
was sharply limited posteriorly by a line corresponding almost exactly with the intra- 
parietal sulcus (the posterior margin of the ascending parietal convolution was slightly 
grazed). From this line the surface of the left hemisphere sloped downwards and 
backwards, and ended abruptly at the point where the middle temporo-sphenoidal 
convolution passes into the occipital lobe. 
Of the convex aspect of the occipital lobe scarcely a trace existed. The anterior 
limb of the angular gyrus, both on its convexity and where it bounds the intraparietal 
sulcus, had disappeared, and as before stated, the posterior margin of the ascending 
parietal convolution was also grazed. 
The convexity of the posterior limb of angular gyrus was also almost entirely oblite¬ 
rated, but the grey matter in the depth of the parieto-occipital fissure was not 
destroyed. The upper extremity of the superior temporo-sphenoidal convolution 
remained clearly defined and intact, except for slight superficial erosion of the cortex. 
The grey matter of the sulci separting it from the anterior and posterior limb of the 
angular gyrus was uninjured. 
The rest of the brain was in every respect normal. [The vertical line seen in the 
figure is an accidental defect in the photograph]. 
Remarks .—In this case we have complete removal of the convexity of the left occipital 
lobe and the greater portion of the angular gyrus followed by transient total blindness 
m the right eye, giving place to right hemiopia ; and this in turn giving place to 
such restoration of vision within a fortnight that no defect could be discovered by 
any methods applicable to the lower animals. 
Experiment IF" (Plate 21, fig. 16). 
In this animal the left angular gyrus and adjacent margin of the ascending parietal 
convolution were exposed and the cortex seared with the galvanic cautery. 
3 S 2 
