38 
PROFESSORS V. HORSLEY AND E. A. SCHAFER 
second gyrus, the tip of the lobe anteriorly and the posterior part of the hippocampal 
gyrus being left intact). The hippocampus major was removed in the greater part of 
its length. 
Result. — We could not detect any deficiency of cutaneous sensibility on the left 
side of the body, nor was any defect of vision perceptible. As regards the other 
special senses, we were unable to arrive at any satisfactory result. The animal was 
kept under observation seven weeks after the operation. 
The brain is represented as seen from below and the right side in fig. 32a, and in 
* section in fig. 32b, 
33. 
Lesion. — Complete removal of the left temporo-sphenoidal lobe, including the hippo- 
campus major. The lesion also involved the under-surface of the occipital lobe. 
Result. — This Monkey survived the operation only two days, so that the results 
are very imperfect, and, owing to the collapsed condition of the animal during that 
time, observations upon the special senses could not be properly conducted. It was, 
however, clearly ascertained that marked diminution, if not complete loss, of tactile 
sensibility was produced upon the opposite side of the body, together with diminished 
sensibility to painful impressions. 
The condition of the brain is illustrated by figs. 33a, b, and c (Plate 5). 
34. 
Lesion. — Removal on the right side of the whole of the lower part of the temporo- 
sphenoidal and part of the lower surface of the occipital lobe. The hippocampus 
major and minor were also excised. The superior temporo-sphenoidal gyrus was left, 
as well as the postero-superior part of the second gyrus. After death it was found 
that there had occurred softening and destruction of the whole of the lower surface 
of the occipital lobe, and a patch of softening also extended round the posterior 
extremity of the hemisphere to the upper surface of this lobe, reaching along the 
mesial edge nearly to the parieto-occipital fissure (fig. 34b). 
Result. — Next day there was no response to tactile impressions applied to the left 
side of the body and left limbs, and lessened response to painful impressions was also 
observed, although both produced a ready response when applied to the right side. 
The day after, the response to painful impressions was somewhat quicker, but tactile 
impressions still produced no reaction on the left side. The defective sensibility of 
the left side was found, however, to undergo gradual improvement from day to day ; 
but even three-and-a-half months after the lesion there was still a dilference of 
sensibility upon the two sides, that of the left side being distinctly lessened. 
Hemiopia was also produced by the lesion, or by the subsequent changes. This 
was of such a character that the right side of both retinoe was blind, i.e., no objects 
were seen which were on the left side of the mesial plane of vision. This hemiopia 
