LESION OF DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 485 
After further observation for half an hour the animal was adjudged to have fair if 
not perfect vision with its right eye, and the left was then unclosed, and the animal 
returned to its cage. 
Next day it was in all respects quite well, and no defect, sensory or motor, could be 
made out. 
Three weeks afterwards the right angular gyrus was similarly exposed and 
cauterised. ’ During the surgical dressing the animal was awake, with both eyes open, 
the pupils large and contractile, and the conjunctival reflex equally distinct in both 
eyes. 
When the animal was allowed free it began almost immediately to run about all 
over the laboratory, avoiding obstacles, and apparently with vision unimpaired, at 
least as regards the power of direction of all its movements. 
After it had run about thus for a time its left eye was then bandaged. On this the 
animal struggled to get rid of it, and in doing so while it ran knocked its head against 
obstacles. It made no sign of perception of threatening gestures, and after observation 
for some time it was adjudged either blind, or to have greatly-impaired vision in the 
right eye. 
Next the right eye was bandaged, the left being freed, whereupon the animal ran 
away, clearing obstacles everywhere, and running away if threatening gestures were 
made. 
Next day the same experiments were repeated on the right and left eye respectively, 
but the animal indicated by its movements and its power to pick up articles of food, 
&c., that it had equally good vision in either eye. No defect, hemiopic or otherwise, 
could be made out. 
The animal continued in perfect health for seven weeks, when the openings in the 
skull were again exposed, and seen to be covered with membrane, continuous with the 
dura mater and flush with the rest, there being no hernia cerebri. 
The posterior margins were incised, and the anterior margins of both occipital lobes 
exposed for about f-ths of an inch behind the cortical lesions previously made. These 
portions of the occipital lobes were cauterised up to the previous lesions. 
During the dressing of the wounds the animal recovered from its narcotic stupor, 
opening both eyes widely. 
The animal was wrapped in a blanket and laid beside the hot-water pipes to recover, 
but having been left for ten minutes it was found free from its blanket and mounted 
on a pipe, and on being approached made grimaces, jumped down, and after a run 
round the laboratory ran into the partially-open door of its own cage, and sprang up 
on its usual perch. All this happened within a quarter of an hour of the operation. 
Not a single symptom could be detected. Its sight seemed unimpaired, hearing 
acute, other sensory faculties and motor powers unaffected. 
The animal continued in good health, and to all appearance normal, until it was 
