554 
PROFESSORS D. FERRIER AND G. F. YEO ON THE EFFECTS OF 
was unaffected towards the right side. The animal was seen to pick up a piece of 
apple lying to its right side. It was also able to crawl through an opening into the 
next cage without knocking its head on one side or the other. 
Next day the animal was found in a comatose condition, and was chloroformed to 
death. 
Post-mortem examination. —The dura mater stripped readily over the whole con¬ 
vexity of the brain, which was quite free from signs of inflammation or effusion ; and, 
with the exception of lesions to be described, the rest of the brain, with the cranial 
nerves, had a perfectly normal appearance. 
In the right hemisphere the posterior half of the middle temporo-sphenoidal, and 
the whole of the inferior temporo-sphenoidal convolution had been sheared off close up 
to the collateral fissure, the lesion extending slightly across it at the middle. But the 
gyrus hippocampi was on the surface almost wholly intact. 
On the left side in the middle of the convex aspect of the occipital lobe posteriorly 
there was a hole, the entrance of the cautery. This had penetrated the lobe down¬ 
wards and forwards and emerged in the line of the collateral fissure, cutting a deep 
groove here on the occipito-temporal surface of the hemisphere. At the lower 
extremity of the collateral fissure the cautery had again buried itself, and emerged at 
an irregularly-shaped orifice, situated at the inferior extremity of the third temporo- 
sphenoidal convolution external to the tip of the gyrus hippocampi. 
The course of the cautery would be indicated by a straight line following the 
direction of the collateral fissure from the occipital lobe to the anterior extremity of 
the temporo-sphenoidal lobe. 
Frontal sections of the brain arranged from behind forwards (Plate 33, figs. 150-15G) 
show that in the right hemisphere (to the right hand) the lesion commenced near the 
junction of the posterior and descending cornu of the lateral ventricle, destroying 
the cortex of the inferior and posterior half or two-thirds of the middle temporo- 
sphenoidal convolutions, and extending so far inwards as in parts entirely to sever 
the medullary connexions of the hippocampal region, and in others so far as to render 
it impossible to mount the sections with all the parts in situ. 
The anterior third of the gyrus hippocampi and cornu ammonis were entirely free 
from lesion. 
In the left hemisphere it is seen that the course of the cautery was through the 
posterior cornu, destroying the cornu ammonis and the medullary fibres of the gyrus 
hippocampi as well as those passing to the inferior and middle temporo-sphenoidal 
convolutions. The cortex of the gyrus hippocampi formed a thin shell, enclosing 
broken-down debris. 
The anterior sections (figs. 155 and 156) show that the course of the cautery passed just 
external to the cornu ammonis itself, severing the gyrus hippocampi and its medullary 
fibres, and also fissuring and detaching the inferior and middle temporo-sphenoidal 
