ON THE FUNCTIONS OF THE CEREBRAL CORTEX. 
29 
13. 
Lesion. — Removal of posterior two-thirds of left gyrus marginalis and a narrow 
adjoining strip of the external surface. 
Result. — Paralysis of right leg. There also seems an inability to rotate the spine, 
but it is diflQcult to be sure of this. No other results were recorded. 
This animal only lived one week, death being the result of enteritis, apparently 
brought on by chill (the room having been accidentally allowed to become cold). 
Except for the lesion, the brain was found to be perfectly healthy, without any sign 
of inflammation of surrounding portions. 
The lesion is represented in fig. 13, Plate 2. 
14. 
Lesion. — Removal of the left gyrus marginalis. 
Result. — Paralysis of right leg and of trunk muscles on right side, so that the 
upper part of the body is turned round to the left. The right arm. is at first partly 
paralysed, but by the third day this had become scarcely perceptible. For the first 
three days the right side of the body and the right limbs react less readily than the 
left to sensory, especially to tactile, impressions, but already on the fifth day this 
difference is no longer to be made out. 
The animal died of enteritis three-and-a-half weeks after the operation. 
The mesial surface of the left hemisphere is represented in fig. 14, Plate 2. 
15. 
Lesion 1. — Right marginal gyrus removed from just behind the sulcus of Rolando 
as far forwards as the anterior extremity of the precentral sulcus. The lower slope of 
the convolution posteriorly was, however, found at the autopsy to have been left. 
Result. — Paralyses not very well marked. Slight paresis of left arm ; when sitting, 
the animal props itself up by right arm, while left arm is kept flexed and adducted. 
It can, however, be freely used. When standing up, the weight of the body rests 
chiefly on the right leg, and in springing this leg is used almost exclusively. Extension 
of hip is deficient (1 wanting) on left side. Left toes paresed ; retain some power of 
grasping, but greatly weakened. 
Lesion 2. — Second opera.tion, seven weeks after the first one. Ascending parietal, 
ascending frontal, and posterior part of first and second frontal gyri removed on 
same side as primary lesion. (This external part of the brain was found to be 
perfectly normal when exposed for operation, although in the previous operation all 
the veins passing from it into the superior longitudinal sinus had been tied. In most 
subsequent operations upon the marginal gyrus these veins were avoided and not tied.) 
Result. — The immediate result of this operation was to produce complete or absolute 
hemiplegia. The right pupil was much dilated, the left contracted. The head and 
eyes were turned to the right, and the face was drawn over to the same side. After 
a few days, however, the hemiplegia appeared somewhat less complete. There was 
