LESION" OP DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 555 
region, as well as implicating to a slight extent the superior temporo-sphenoidal where 
it borders on the first temporo-sphenoidal fissure. 
The crura cerebri, internal capsule, and central ganglia are seen to be free from 
lesion in both hemispheres. 
Remarks .—This case shows that destruction of the whole of the inferior temporo- 
sphenoidal, and portion of the middle temporo-sphenoidal convolutions, with con¬ 
siderable destruction of the medullary fibres passing to the gyrus hippocampi and 
cornu ammonis, only partially impaired tactile sensibility on the opposite side. 
At first the impairment was very distinct, and amounted almost to analgesia, but 
this gradually gave way and ultimately entirely disappeared, So that within a fort¬ 
night it was not possible to discover any difference in the reactions of the two sides. 
Sight and hearing were unimpaired from the first, and there was no motor paralysis. 
The subsequent destruction of the hippocampal, and medullary fibres of the 
inferior temporo-sphenoidal region on the left, induced almost absolute analgesia as 
well as complete insensibility to mere contact on the right side ; motor power, vision, 
and hearing being clearly retained. 
(Jnfortunately the permanency of the symptoms could not be determined owing to 
the death of the animal very shortly after the establishment of this lesion. 
Experiment 31 (Plate 34, figs. 157-163). 
In this animal the left hemisphere was exposed in the region of the incisura prae-occipi- 
talis, and two incisions made with the cautery, one along the posterior border of the 
middle temporo-sphenoidal convolution, and another horizontally inwards from the 
upper extremity of this incision so as to divide the upper or posterior portion of the 
gyrus hippocampi from the rest. The portion of brain included between these two 
incisions was disorganised by the cautery, and the surface touched with perchloride of 
iron to arrest haemorrhage. 
An hour after the operation the animal, which had quite recovered consciousness, 
was very unsteady when it tried to move about, falling down on the right side. 
Heat applied to any part of the right side caused barely any sign of reaction, 
whereas on the left the most lively signs of sensation were evoked. 
Some time subsequently while the animal was being held numerous tests were 
made as to tactile sensibility. Pricking and pinching the fingers and toes of the right 
side caused very slight if any indications of sensation, but on the left the same caused 
the animal to exhibit signs of uneasiness, rub the part, and struggle to get away. 
Tickling the interior of the right nostril caused no reaction, on the left the same 
caused the animal to rub its nostril with its hand and make a grimace. The animal’s 
tongue protruded at the tip and the right side could be touched and pricked gently 
with the point of a pin without causing any reaction, whereas on the left the same 
caused the animal to rub at the part. 
4 b 2 
