LESION OF DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 547 
inti’oduced into the right nostril caused little or no sign of uneasiness, whereas on the 
left the animal made a violent grimace and active endeavour to escape. 
The vapour of ammonia in the left nostril caused very active wincing. On the 
rig;ht the reaction was much less marked. 
On testing the resistance of the limbs, that of the right seemed much less than on 
the left, but every movement was carried out on the right as well as left. 
The tendency to fall down on the right side was sjDecially seen when the animal dozed. 
When resting on its perch it frequently slipped on the right, and only succeeded in 
recovering its balance with the aid of the left limbs. 
The animal, which seemed quite well in general health on the second day, was 
found dead on the third day from some unknown cause. 
Post-mortem examination .—The edges of the wound looked rather inflamed, which 
made it appear as if the antiseptic precautions had not been successful. The signs of 
inflammation and slight oozing were, however, entirely confined to the tissues of the 
scalp and edges of the wound. 
There was no hernia cerebri, and there was no effusion on the surface of the brain ; 
but on removal of the brain the left middle fossa was found filled with a recent clot 
which had come from the injured surface of the brain, and which was evidently the 
cause of death. The effusion did not extend to the base of the brain. 
All the cranial nerves were intact and normal, and so also were the pons, medulla 
oblongata, and cerebellum on its upper and under surface. 
On carefully separating the gyrus hippocampi from the optic tract and crus on the 
left side, the inner margin of the gyrus was found uninjured and not adherent to the 
optic tract or crus. The optic tract was followed readily to tire corpora geniculata, 
pulvinar and corpora quadrigemina, all of which were uninjured. (See fig. 125.) 
Along the inner edge of the gyrus hippocampi, the fimbria of the fornix, and the 
taenia semicircularis were seen intact, and could be followed to the uncus gyri hippo¬ 
campi, which with the outer root of the olfactory tract was uninj ured. 
With the exception of a portion of the gyrus hippocampi (lingual lobule) imme¬ 
diately adjoining the calcarine fissure, the whole of the hippocampal region and inferior 
temporo-sphenoidal region had been destroyed. The lesion trenched on the middle 
temporo-sphenoidal convolution (fig. 126), but the greater portion of this remained 
uninjured. The inferior occipital convolution was also carried away. 
The lesion might be described as an incision following the line of the second occi- 
pital sulcus continued to the extremity of the second temporo-sphenoidal sulcus, 
extending horizontally inwards and detaching the whcle of the occipito-temporal sur¬ 
face of the hemisphere, as far as the hippocampal fissure, and within a short distance 
of the calcarine fissure. 
Frontal sections through the left hemisphere (figs. 127-132), arranged from behind 
forwards, show that some portions (fig. 127) still remained of the gyrus hippocampi 
and hippocampus itself in the neighbourhood of the calcarine fissure. In fig. 129, 
4 a 2 
