458 
DR. D. FERRIER ON THE BRAIN OF MONKEYS. 
fissure of Sylvius below the inferior occipital fissure to the edge of the uncinate convo- 
lution on the internal aspect. 
In the right hemisphere the fungating mass occupied about the same extent as in the 
left, but extended somewhat further backward into the occipital lobe. 
The temporo-sphenoidal lobe was not divided to the same extent transversely ; but a 
deep excavation occupied the centre of the fungating surface, and corresponded to the 
level of the upper end of the middle temporo-sphenoidal convolution (fig. 16). The 
internal aspect of the temporo-sphenoidal lobe was of normal appearance. 
The rest of the brain was normal. 
On examination after the brain had been hardened in spirit for 20 hours, it was found 
that in the left hemisphere the transverse division extended almost to the hippocampus. 
The whole of the interior of the lobe below this point was reduced to a pulp, the 
softening extending to some extent between the lips of the fissure of Sylvius, and 
affecting the surface of the island of Reil to a slight extent. 
The grey matter of the lower half of the temporo-sphenoidal convolutions and of the 
uncinate gyrus formed a sort of shell, enclosing softened medullary substance. The 
hippocampus was disorganized as far as the subiculum cornu ammonis. The optic tha- 
lamus was not injured. 
In the right hemisphere the excavation extended to the extraventricular surface of 
the optic thalamus, but the hippocampus and fornix could still be seen of normal or 
almost normal appearance. The internal or medullary surface of the superior and 
middle temporo-sphenoidal convolutions was softened to a slight extent below the point 
of greatest depth of the wound on the hemisphere. The subiculum and the lower ends 
of these convolutions are not injured externally. 
In this experiment the results as regards hearing were such as to indicate abolition, 
or at least considerable impairment, of reaction to stimuli which in the ordinary con- 
ditions are responded to actively. So far, therefore, the theory that this is dependent 
on the destruction of the superior temporo-sphenoidal convolution holds good, for this 
convolution was divided or disintegrated almost completely on both sides. 
The reaction to acetic acid in the nostrils is not to be taken as a sign of the reten- 
tion of true smell, for it in all probability was more due to irritation of nerves of 
common sensation. 
The reaction, however, was decidedly diminished, and was not caused when the 
vapour was held only before the nostrils. 
The absence of reaction on the tongue points to impairment of the sensation of taste, 
and perhaps the want of desire to eat may have its explanation in loss of this faculty. 
The experiment, however, is not regarded as conclusive, and is to be taken in 
connexion with other facts. It is brought out more clearly than before that the loss 
of tactile sensation coincides with lesion of the hippocampus and hippocampal convo- 
lution. This region was quite destroyed on the left side, and loss of tactile sensation 
was observed on the opposite side ; while on the left side tactile sensation apparently 
