5G4 PROFESSORS D. FERRIER AND G. F. YEO ON THE EFFECTS OF LESIONS, ETC. 
difficult and fraught with great risks, either of injury to the crus cerebri or of 
secondary haemorrhage, and I have, unfortunately, not succeeded in maintaining any 
animal, in which this lesion was successfully established, sufficiently long ahve to 
determine the questions that arise with respect to permanency or compensatory 
action. In Experiment 25 the greatest amount of damage was inflicted with long 
survival, but the anaesthesia in this case was only partial from the beginning, and 
the lesion did not destroy the whole of the hippocampal region. 
It is comparatively easy to secure total destruction of the hippocampal and lower 
temporo-sphenoidal region by operations conducted without antiseptic precautions, as 
the primary lesions become the centres of secondary inflammatory processes. In all 
cases where this occurred the anaesthesia, at first partial, deepened and became 
absolute. But this condition is incompatible with long survival or accurate determi¬ 
nation of the extent of the primary lesion. 
In addition to the positive evidence furnished by these experiments in favour of the 
localisation of the centres of tactile sensibility in the hippocampal region, I would also 
adduce the negative effect as regards tactile sensibility of all the other cerebral lesions 
here recorded, involving the occipital, parietal, and frontal lobes. In none of these, 
however extensive, was any impairment of tactile sensibility observed, even of the 
most transient duration. 
