464 
DR. D. TERRIER ON THE BRAIN OE MONKEYS. 
following the destruction of this region of the brain, be taken with the phenomena 
resulting from electrical stimulation of the same part, we have, it appears to me, as 
satisfactory proof as it is possible to obtain from the lower animals, that the sense of 
hearing is localized on the superior temporo-sphenoidal convolution. 
Having thus eliminated the result of destruction of this convolution from the complex 
effects caused by more extensive lesions of the temporo-sphenoidal lobe, I proceed to 
describe experiments tending to fix more definitely the seat of tactile perception. 
Several experiments have already been detailed, which rendered it more than pro- 
bable that the loss of tactile sensation was dependent on lesion of the hippocampus 
major or uncinate convolution, or both. 
Experiments were devised for the purpose of destroying this region without injury to 
the rest of the temporo-sphenoidal lobe. To effect this seems almost impossible, consi- 
dering its deep-seated and concealed position in the internal aspect of the hemisphere. 
The method I at last resolved to pursue was to endeavour to reach this from the 
occipital region by passing heated wires through the posterior aspect of the occipital 
lobe in the direction of the hippocampus. I had first ascertained the negative effects 
of destruction of the occipital lobe. These will be related subsequently. 
Having made repeated experiments on the dead brain, so as to acquire knowledge of 
the direction and extent to which the cautery should be pushed, I proceeded to expe- 
riment on the living animal. 
My first attempts were not quite successful, as will be seen, but ultimately my efforts 
were rewarded with success. 
Experiment XVI. 
February 5th, 1875. — This, though not successful as regards the object intended, yet 
presents some interesting phenomena. The left occipital lobe was exposed posteriorly, 
and penetrated at the posterior extremity of the superior occipital fissure by means of 
hot wires, which were directed with a view to follow the inner aspect of the temporo- 
sphenoidal lobe. There was no hsemorrhage from the sinus. During the operation the 
animal was observed to make sighing respiration. The operation was finished at 4.30 p.m. 
The animal lay in a state of stupor for more than an hour, only making slight move- 
ments when disturbed, and then with its left limbs. 
7 p.m. The animal lies quiet, but indicates consciousness by grunting discontentedly 
when moved. Struggles with its limbs, chiefly the left, but occasionally with the right. 
On testing the cutaneous sensibility with the hot iron, reaction was decisive over the 
whole of the left side, but quite abolished on the right. The animal occasionally 
opened its right eye, but the left remained permanently closed. The animal passed into 
a state of coma, and was found dead at 11.30 p.m. 
Post mortem Examination (next morning). — It was found that the cautery, as indi- 
cated by the blackened sinus, had penetrated the occipital lobe at the point mentioned, 
where a round hole was situated, and on emerging had ploughed a furrow on the upper 
