40 
PKOFESSORS V. IIORSLEY AND E. A. SCHAFER 
arm, but produces no reaction elsewhere upon the right arm and hand unless heated 
to excess. The ear and the right side of the head are apparently as sensitive as on 
the left side, but the right leg, although by no means anaesthetic, is distinctly less 
sensitive than the left. The leg, trunk, and arm muscles appear weakened, although 
the right limbs are still freely used. The animal is to all appearance quite well and 
lively. 
" Two days later (on the third day) the condition as regards sensibility is exactly the 
same, but the pareses, especially of the leg, are less marked. 
" During the rest of the week following the operation the symptoms are much the 
same, but the right side seems to be slowly recovering. It requires, however, a 
considerable stimulus to produce any response, and the interval between the stimulus 
and the response is much lengthened ; the reaction, when it does appear, being often 
of the nature of a sudden start. There is also some failure to localise the seat of 
irritation, and the left limb is often scratched by the animal each time that the right 
limb is irritated (condition of allochh^ia). The right arm and leg are still paresed." 
The animal was kept for seven weeks, at the end of which time the difference of 
sensibility was still apparent upon the two sides, both for tactile and painful sensibility 
(prick, heat, induction shocks), although it had distinctly diminished. 
An attempt was then made to remove the gyrus .fornicatus of the other side, but 
the animal succumbed to the shock of the second operation. 
The left hemisphere is represented on its mesial aspect in fig. 36. From the 
superficial view, the lesion of the gyrus fornicatus appears less extensive than is 
actually the case, for sections showed that this convolution, although imperfectly 
removed, was undermined by the incision that was made along it preparatory to its 
ablation. 
37.* 
Lesion 1. — The anterior part of the left gyrus fornicatus was removed from about 
the level of Y forwards. 
Result. — The external ear of the opposite side gives no reaction either to tactile 
impressions or to impressions producing pain elsewhere (prick, heat, electric shocks). 
It could not be determined whether any other parts were as completely insensible. 
Lesion 2. — One week later the greater part of the remainder of the convolution was 
cut away. 
Result. — " There is great diminution of sensibility over the whole of the right side. 
Tactile impressions are not perceived, or at least produced no reaction ; painful 
impressions, such as a prick or a burn, are only slowly perceived and are then not 
localised. To every such stimulus, no matter to what part of the right side it is 
applied, the animal responds in the same manner, viz., by scratching the right fore-arm." 
This phenomenon (a form of allochiria) was exhibited for about a week after the 
second operation ; it then disappeared. 
. * This animal was exhibited to the Physiological Society. 
