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PROFESSORS D. FERRIER AND G. F. YEO ON THE EFFECTS OF 
upper extremity of the superior temporo-sphenoidal convolution was eroded 
superficially. 
The rest of the brain was perfectly normal. 
Remarks. —In this case of superficial destruction of the cortex of the left angular 
gyrus and ascending parietal convolution there was no perceptible affection of vision on 
the side of lesion, and none could be made out on the opposite side within two hours 
after the operation. The right hand was somewhat weaker than the left, but there 
was no paralysis of any movement. 
The subsequent entire removal of the right occipital lobe and considerable destruc¬ 
tion of the right angular gyrus caused defect in vision in both eyes which proved to be 
of the nature of hemiopia to the left. By repeated tests applied to the right and left 
eye respectively, it was found that the limitation of vision towards the left was greater 
in the left eye than in the right. 
The hemiopic defect gradually diminished, and within three weeks after the second 
operation it was not possible to discover in the animal’s behaviour or mode of activity 
any such defect as had been at first so evident. 
Experiment 12 s (Plate 21, figs. 20, 21, and 22). 
In this animal both angular gyri were seared by the galvanic cautery, and both 
occipital lobes severed and scooped out. The portion removed from the right side 
weighed 2'25 grms., that from the left weighed 2‘5 grms. On recovery of conscious¬ 
ness the animal was observed to have both eyes open, the pupils of moderate size, and 
the conjunctival reflex distinct on both sides. This was seen within a quarter of an 
hour after the operation was finished. 
An hour after the operation the animal was able to walk about, moving all its limbs 
perfectly. Tactile sensibility was unimpaired, judging by its attention to and dislike 
of being touched on any part. That it could smell was indicated by a sudden grab at 
a piece of apple placed under its nose, which however it failed to seize. 
It was absolutely blind and knocked its head against everything in its path. The 
slightest sound made in its vicinity caused it to start and look round. 
Next day it was well and vigorous. Muscular powers were unimpaired, and every 
faculty of sense except vision. In this respect it was totally deficient, making no sign 
of perception of anything in the way of threats, &c., and yet so shy and timid that the 
slightest touch caused it to start and endeavour to escape. In such attempts it 
knocked its head full against whatever lay in its path. 
Next day the condition was the same. The animal took its food when this was 
put in its hands, but could not find anything that was merely offered to it, or that 
accidentally dropped from its grasp. 
A week subsequently it was still in the same condition ; well in health, and in no 
wise deficient except as regards vision. An ophthalmoscopic examination of the eyes 
showed the media, retina, and optic discs of perfectly normal appearance. 
