LESION OF DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 557 
over the whole of the right side. The demonstrations of sensation to heat, pinching, 
pricking, &c., were much more lively on the right side than on the left, and the sensa¬ 
tion caused by plucking the hairs on the right hand was, judging from the animal’s 
gestures, much more acute on the right side. 
Gentle sounds near the right ear caused the animal to turn and look exactly as on 
the left. The condition as to vision was not determined this day. 
Next day the animal was able to run about actively and climb as usual. Hearing 
was evidently equally acute on both sides, but there seemed some impairment of vision 
towards the right. No difference could be detected as regards smell in the two 
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nostrils. When a fine wire dipped in oil of bergamot was held to each nostril—the 
other being closed—the animal sniffed equally as if smelling. (This odour seems very 
agreeable to Monkeys, as they always sniff it as if enjoying it.) 
As to tactile sensibility no difference could be made out between the two sides. 
The hypersesthesia of the day before had disappeared. 
On the seventh day there still seemed slight uncertainty as to the exact position 
of things on the extreme right, but the animal was able to pick up things lying on the 
floor of the cage to the right as well as to the left side. 
On the tenth day the animal seemed perfectly normal in respect to all its faculties 
and powers. 
Four weeks subsequently to the first operation the right hemisphere was exposed 
over the region of the incisura prse-occipitalis, and by means of a cautery, guided by a 
director, the temporo-sphenoidal lobe was incised along the middle temporo-sphenoidal 
convolution and also horizontally inwards towards the gyrus hippocampi. The portion 
of brain between the two incisions was left in situ , with a view to prevent tire risk of 
secondary haemorrhage, which had previously proved so fatal. 
Within half an hour after the operation the animal was able to sit up, but 
unsteadily, the left limbs being planted awkwardly, and tending to double up. 
Tactile sensibility at this time was greatly impaired all over the left side. The 
animal allowed a degree of heat which excited the most lively demonstration, and 
rubbing of the part touched, on the right side, to be applied to the left side of the 
tail, trunk, hand, and foot without making any sign of uneasiness. 
So also pricking, gently tickling and ruffling of the hair on the left side caused no 
sign of perception, whereas on the right the animal invariably put its head or foot to 
the part, and in so doing fell over on the left side. 
Tickling of the right nostril caused evident sign of uneasiness ; of the left no 
perceptible sign. 
The condition as to hearing and vision on the left was not determined. Hearing was 
undoubted towards the right however. 
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Next day vision was seen to be unimpaired to both sides, the animal picking up 
minute objects to either side equally well. Hearing also was retained in the left ear 
—the animal turning to sounds on the left exactly as on the right. 
