LESION OF DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 537 
unimpaired as regards their motor power, were for a time markedly defective as 
regards sensibility. 
Notwithstanding the extensive lesion of the hippocampal region, there was no trace 
of descending degeneration in the opposite side of the spinal cord, though the animal 
had lived more than a year after the establishment of the lesion in question. 
Experiment 25 (Plate 29, figs. 110-116). 
In this animal the right occipital lobe was first exposed, and a wire cautery was 
thrust through the lobe at the anterior extremity of the superior occipital sulcus, in 
the convex aspect of the lobe, downwards and forwards, with a view to plough along 
the hippocampus. 
While the animal was recovering during the application of the surgical dressings the 
right pupil was observed to be somewhat smaller than the left. When set free the 
limbs on the left side were moved and planted with some appearance of uncertainty. 
An hour and a half after the operation there were signs of defective vision towards the 
left side, as the animal did not appear to observe threatening gestures made on the 
left, whereas it made grimaces when the same were made on the right front. 
Repeated tests were made as to the effects of thermal stimulation on the right and 
left side respectively, with the result of showing that though signs of sensation could be 
elicited on the left as well as on the right, they were much less distinct on the left 
side, whether on the ear, hand, trunk, foot, or tail. 
Next day similar observations were made as to the effects of heat, with similar 
results. As to the perception of mere contact, it was not easy to determine, as the 
animal was shy and difficult to approach. But as it was still hemiopic towards the 
left side, advantage was taken of this, and a long wire (cold) stuck in the end of 
a stick was made to come into contact with the hands and feet from the left, without 
attracting the animal’s sight. 
When the fingers or toes of the right side were touched gently, or scratched in this 
manner, the animal invariably looked and changed its position ; but when the same 
was done on the left there was not the slightest sign of perception, and no change in 
position was made. This was repeatedly verified. 
Next day similar observations were made with similar results, but occasionally there 
seemed to be less difference than before. But the left side of the tail was pricked with 
a pin without causing any sign of sensation, whereas the same on the right caused the 
animal to turn round and scratch the place in a lively manner. The left liemiopia was 
still apparent. 
On the eighth day the animal was seen to run about most actively, never knocking 
its head on one side or the other against any obstacles in its path. The hemiopic 
defect previously existing was now very doubtful. 
The cremasteric and cutaneous plantar reflexes appeared somewhat more active on 
the left side than on the right. 
3 z 
MDCCCLXXXIV. 
