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PROFESSORS D. FERRIER AND G. F. YEO ON THE EFFECTS OF 
inferior temporo-sphenoidal convolutions, tlie hippocampal region was in great measure 
detached and destroyed, induced the most profound anaesthesia of the left side. But 
here again, as in many previous experiments of a similar nature, the animal speedily 
succumbed, so that further observations with regard to the permanency of the 
symptoms were rendered impossible. 
X 
General Results. 
The experiments recorded in this section show that by destructive lesions confined to 
the cortex and medullary fibres of the inferior and internal aspect of the temporo- 
sphenoidal lobe, without implication of the crus cerebri, basal ganglia or internal 
capsule, it is possible to cause complete anaesthesia (cutaneous, muscular, and mucous) 
of the opposite side of the body, without paralysis of voluntary motion. 
In the operations necessary for the establishment of such lesions a certain amount of 
injury of other regions is unavoidable, but an analysis of the experiments, varied as 
to the method of performance and the extent to which other regions were involved, 
shows that the only point in common to all the cases in which there was impairment 
or abolition of tactile sensibility, was destruction of the cortex and medullary fibres of 
the hippocampal region ; and the degree of impairment of tactile sensibility was in 
proportion to the extent to which this region was involved. 
In my former experiments (Philosophical Transactions, Vol. 165, Part 2) I had 
observed that in several cases of lesion of the temporal lobe, tactile anaesthesia super¬ 
vened when in the process of secondary softening the hippocampal region became impli¬ 
cated. In Experiments XVII. and XVIII. lesions were purposely primarily established 
in this region. In Experiment XVII. anaesthesia was not observed till the third 
day :—the track of the cautery, as was proved post-mortem, having swerved away 
from the hippocampal region. But as softening invaded the hippocampal region 
anaesthesia became established. The sections of the hemisphere (figs. 89-94) show 
that the lesions were confined to the cortex and medullary fibres of the hippocampal 
and inferior temporo-sphenoidal region. 
In Experiment XVIII. anaesthesia followed the lesion immediately, and the animal 
was killed before any secondary changes could be developed. The sections of the 
hemisphere show that the lesion was strictly confined to the hippocampal and lower 
temporo-sphenoidal region (figs. 97—102). 
In reference to lesions of the temporal lobe not specially invading the hippocampal 
region, Experiment 14 is of importance. In this case the region of the middle and 
inferior temporo-sphenoidal convolutions was disorganised without any indications of 
tactile anaesthesia. Some extension of the primary lesion occurred secondarily, but 
whether any anaesthesia resulted was not observed. The fact of importance is that 
the primary lesions were without discoverable effect on tactile sensibility. 
In Experiment 26 also, though the lower temporo-sphenoidal region was destroyed. 
