558 
PROFESSORS D. FERRIER AND G. F. YEO ON THE EFFECTS OF 
As to tactile sensibility there seemed improvement as regards analgesia, but the left 
side could still be touched, tickled, &c., without exciting attention. On the right side 
the animal invariably put its hand to the place. 
On the third day the difference between the two sides as regards tactile sensibility 
was less pronounced. In all other respects the animal was perfectly well. 
Omthe sixth day no difference could be made out between the two sides in respect 
to tactile sensibility. The animal continued from this time in perfect health, and was 
killed with chloroform a month subsequently—or two months after the first operation. 
Post-mortem examination. —The cranial openings Avere covered by membrane adherent 
to the subjacent cortex, but elsewhere the whole surface of the brain was free from 
adhesions. 
Except for the lesions about to be described all the rest of the brain was perfectly 
normal. 
At the posterior extremity of the left occipital lobe there was a ragged sinus or 
channel marking the point where the cautery had been introduced. This pierced the 
tip of the occipital lobe and then immediately emerged, grooving the surface of the 
gyrus hippocampi (lingual lobule) between the calcarine and collateral fissures. The 
cautery then ran along the margin of the hippocampal or dentate fissure and plunged 
ultimately into the nucleus amygdalae or tip of the gyrus hippocampi. The optic 
tract though so near the course of the cautery was in a most remarkable manner 
absolutely untouched, and Avas freely separable and traceable to the corpora geniculata 
which Avere altogether free from lesion. 
In the right hemisphere there was a deep incision occupying the position of the first 
temporo-^phenoidal sulcus in its lower half; and from the upper extremity of this, on a 
level with the anterior extremity of the inferior occipital convolution, there was 
another deep incision at right angles to the axis of the temporo-sphenoidal lobe, 
extending exactly to the collateral fissure. The portion of brain included betAveen 
these two incisions remained in situ. 
The whole superficial aspect of the gyrus hippocampi was quite intact (fig. 164). 
Sections of the brain, parallel to the fissure of Rolando (Plate 35, figs. 165-172), 
show that in the left hemisphere the internal margin of the gyrus hippocampi, at the 
junction of the posterior and descending cornu of the lateral ventricle (figs. 165 and 
167), is grazed. Figs. 169 and 170 show that the fascia dentata has been sheared off 
In fig. 171 a portion of the alveus of the cornu ammonis has been carried away, and 
in fig. 172 a perforation of the nucleus amygdalae indicates where the cautery left 
the hippocampal fissure and plunged into the extremity of the gyrus hippocampi. 
The lesion is entirely confined to the fascia dentata and ah T eus of the cornu ammonis, 
without in any Avay injuring the medullary fibres of this or of the gyrus hippocampi 
itself. 
In the right hemisphere the gyrus hippocampi and cornu ammonis and the medul¬ 
lary fibres passing to this region are seen to be uninjured posteriorly (figs. 166, 16S, 169). 
