DE. D. FEEEIEE ON THE J3EAIN OF MONKEYS. 
461 
and easily separable from the convolutions overlapping it. The lower part of the 
ascending frontal convolution was slightly softened and congested. 
In the right hemisphere the surface of the lower half of the temporo-sphenoidal 
convolutions was quite disintegrated and blackened (fig. 19). The subiculum cornu 
ammonis was broken up. The softening did not extend to the fissure of Sylvius. The 
internal aspect of the lobe, the hippocampus, and uncinate convolution were normal, 
except at the subiculum, as already described. No other injury existed in any part of 
the brain. 
This experiment was followed by results of a very remarkable character. 
There was absence of reaction to stimuli of smell, taste, hearing, and of tactile 
reaction on the right side (almost complete). 
As regards the loss of tactile sensibility, we have again the apparent connexion of 
this with destruction of the hippocampal region. 
On both sides the subiculum cornu ammonis was broken down, and on both sides 
there was absence of any reaction indicating olfactory sensation. 
A peculiarity, however, existed in the comparative reaction of each nostril to the 
effect of acetic acid. In the left nostril, i. e. the side on which tactile sensibility 
remained, acetic acid caused a copious flow of tears from the left eye, while in the right 
nostril no effect of any kind was produced. This is evidently to be ascribed to the 
abolition of common sensibility as well as of true smell from the right nostril. The 
lacrymation was the indication of the reflex excitation of the lacrymal gland through 
the medium of tactile sensibility, which still continued unimpaired on the left side. 
The absence of motor reaction, however, was an interesting fact, and serves to show how 
much of the reaction caused by a pungent vapour applied to the nostril is dependent 
on the integrity of true olfactory sensibility. 
As regards taste, the results indicated its entire abolition. But not only taste, as 
such, but also the tactile sensibility of the tongue seemed to have been destroyed. 
This was noted as a remarkable phenomenon, and the tests were frequently repeated in 
order that no fallacy might be allowed to remain. Not only on the right side of the 
tongue, but also on the left, was this absence of reaction noted. The centres for the 
tactile sensibility of the tongue on the left side seemed to have been destroyed along 
with those of special sense, a fact apparently indicating their close anatomical relation 
in the hemisphere. The following experiments serve to narrow the boundaries of the 
lesions causing these various results as regards hearing and tactile sensation. 
Experiment XV. 
April 7th, 1875. — The subject of this experiment was the same monkey used for 
Exp. IX. 
After the animal had quite recovered from the effect of destruction of the angular 
gyrus on the left side, it was again chloroformed, and the superior temporo-sphenoidal 
