544 
PROFESSORS D. FERRIER AND G. F. YEO ON THE EFFECTS OF 
cautery emerged from the occipital lobe, but the greater portion remained intact. (See 
Plate 30, fig. 117.) 
Right hemisphere .— The occipital lobe was much injured and broken up at its 
posterior extremity. This lobe was truncated owing to the complete removal of the 
posterior extremity, and the cortex was removed in the middle of the lobe as far as 
the joarieto-occipital fissure. 
The under aspect of the lobe was completely hollowed out by a sinus which occupied 
the position of the calcarine fissure and its margins. These were entirely destroyed. 
Thence downwards and forwards a remarkable appearance was presented. The gyrus 
hippocampi was completely shelled off the cornu ammonis as far as the region of the 
uncus, the cornu ammonis with the fascia dentata being thus exposed to view as if by 
an exquisite dissection. (See fig. 117.) 
The internal margin of this, adjoining the optic tract, was absolutely uninjured, and 
the fimbria of the fornix, and the taenia semieircularis were beautifully displayed on 
drawing the parts slightly asunder. 
In the figure the course of the optic tract to the corpora geniculata and pulvinar 
has been exposed by tearing off the pia mater and slight separation of the parts from 
each other. 
Sections were made of the brain obliquely downwards and forwards, parallel to the 
fissure of .Rolando, of which sun-prints are seen in figs. 118-124. The plane of 
section was not at right angles to the long axis, but sloped somewhat towards the 
left, thus causing some obliquity in the sections. The plane of section strikes the 
convexity of the occipital region and middle of the hippocampal region. 
Figs. 118-119 (L), and 120-121 (R) show the appearance presented by the sections 
which have not yet struck the central ganglia. On the left side the track of the 
cautery is seen to divide the medullary fibres and cortex of the gyrus hippocampi at 
the region where it emerged in the collateral fissure ; but the hippocampus itself and 
the gyrus hippocampi internally are intact, as was also seen in the photograph of the 
brain (fig. 117). 
The right occipital lobe in the region of the calcarine fissure is hollowed out, the 
walls of this fissure being entirely destroyed, and in continuity with this the gyrus 
hippocampi has been peeled off the cornu ammonis which is free and uninjured;— 
being attached only by some of the medullary fibres proceeding to it. 
In fig. 122, which cuts the region of the corpora quadrigemina and posterior aspect of 
the optic thalami and the anterior extremity of the hippocampal region, a notch on 
the left side, external to the gyrus hippocampi, indicates a transverse section of the 
groove which ploughed along the collateral fissure; and a notch on the under surface 
of the gyrus hippocampi on the right side indicates the termination of the lesion 
which peeled off this gyrus from the cornu ammonis. 
In figs. 123 and 124 on the left side the groove in the collateral fissure is still seen, 
but penetrating less deeply into the medullary fibres of the hippocampal region ; while 
