OF THE GYRUS MARGIHALIS AND GYRUS FORNIOATUS IN MONKEYS. 341 
Here the sclerosis has the shape and position characteristic of degeneration following 
marginal lesions, being claw or wedge shaped, with tire base towards the posterior 
cornu, and the apex extending forwards and outwards until it reaches the circum¬ 
ference about the middle of the lateral column, whej’e it sj)reads out, and joins 
posteriorly the degeneration which occupies the superficial part of the direct cere¬ 
bellar tract region. The degeneration is relatively less in amount than in the cervical 
n'gion. 
Lumbar Enlargement. —The degeneration is small in amount, and lies on each side 
close to the circumference of the sections, in the angle formed by the posterior root. 
Case 7.— No. 36 of First Series. 
Lesion. —Removal of a considerable part of the left gyrus fornicatus. The marginal 
convolution was found to be injured in the greater part of its extent (‘ Phil. Trans.,’ 
B, 1888, Plate 6, fig. 36). 
Result. —The whole of the right side of the body, as far as the iliac crest, was almost 
completely insensible to touch, prick of a pin, and to a jet of cold water suddenly 
applied. There was loss of sensibility over the right arm. The right leg, although 
not anmsthetic, was far less sensitive than the left. The arm, leg, and trunk are 
paresed, althongh they are still used. There was incomplete recovery from the paresis. 
The animal died seven weeks after the operation. 
Degenerations Observed. 
Midbram amd Pons. —Extensive scattered degeneration can be seen in the pyramidal 
bundles of the left side. 
Medulla. —The degeneration in the pyramids is very extensive on the left side, more 
so than in simple marginal lesions. 
Spinal Cord. Cervical Enlargement. —On the right side there is extensive scattered 
degeneration in the crossed pyramidal tract, involving the greater part of the area 
occupied by this tract. _ The degeneration forms a broad triangular patch, extending 
from the posterior cornu outwards and forwards, reaching the circumference a little 
behind the middle of the lateral surface (corresponding with the area of the crossed 
pyramidal tract). 
From the postero-lateral groove there extends, close to the circumference, a narrow 
band of degeneration in the outer part of the direct cerebellar tract region, which 
joins, as it passes forwards, the anterior and external end of the degeneration in the 
crossed p_yramidal tract; so that this latter degeneration and that extending along 
the circumference enclose between them a band of healthy fibres of the direct cere¬ 
bellar tract. 
There are a few degenerated fibres to be seen in a similar position on the opposite 
side of the cord (left). 
