LESION" OF DIFFERENT REGIONS OF THE CEREBRAL HEMISPHERES. 483 
half a centimetre in diameter—more on the right than left—instead of three-quarters 
of an inch, the original extent of the lesion. The greater portion of the middle and 
inferior frontal convolutions had been destroyed. 
The caudate nuclei were uninjured, as also the rest of the brain. 
Remarks— This case shows that lesions may be made simultaneously in both 
occipital lobes without any perceptible impairment of vision, or other defect. Not¬ 
withstanding the subsequent considerable destruction of the cortex in both prefrontal 
regions, there was no perceptible physiological defect either as regards motion or 
sensation, general or special. 
Further observations on the effects of lesions of the prefrontal regions will be 
found detailed in Section IV. In this case a psychological alteration was very 
evident but difficult to define, shown more particularly in listless apathy, contrasting 
strongly with the previous vivacity and active curiosity which characterised the 
animal. 
Experiment 3“ (Plate 20, fig. 4). 
In this case the right angular gyrus was exposed, and the cortical matter of the 
convexity of both limbs was destroyed by the galvanic cautery. 
After the narcotic stupor had passed off, the eyes were observed to be both widely 
open, the pupils small and equal, and the conjunctival reflex equally distinct on both 
sides. 
Both eyes were left open and the animal left to itself. For an hour it seemed quite 
disinclined for exertion, but at the end of this time began to move about, occasionally 
replying to grunts from its companions. 
A quarter of an hour afterwards it put out its hand to take a piece of apple offered 
it, but seemed to be uncertain as to the exact position and distance. 
An hour after this the right eye was bandaged. The animal seemed then very 
unwilling to move, and when it did, knocked its head on several occasions against 
some obstacle, and sat down. When placed in its cage it would do nothing but lie 
down. After this had been observed for a quarter of an hour the bandage was 
removed from tire right eye, whereupon the animal began to look about, and though 
it would not run about the laboratory very freely, when placed in its cage it at once 
jumped on to a hot-water pipe which ran along the back of its cage and remained 
there. 
Next day the animal seemed perfectly well, and took things offered it with the 
utmost precision. 
The right eye was then bandaged, but though the animal seemed to dislike the 
bandage, and would not run about spontaneously, it did so when urged, and showed 
no signs of impairment of vision, passing obstacles on every side without hesitation or 
knocking its head. It was able also to lay hold of things offered it on either side. 
Similar observations were made on the following day, and with precisely the same 
results. 
3 Q 2 
