DR. D. FERRIER ON THE BRAIN OF MONKEYS. 
445 
Experiments relating to the Localization of Sensory Perception * . 
Certain movements of the eyes, ears, and nostrils, obtained by stimulation of certain 
convolutions already described, led me to regard them as the external manifestations of 
sensations thus subjectively aroused; and the following experiments were directed to 
test the truth of this hypothesis, and to determine to what extent sensory localization 
in the brain might be possible. 
Destruction of the Angular Gyrus. 
As already related, electric stimulation of this convolution caused movement of the 
eyeballs to the opposite side, with a direction upwards or downwards, according as the 
anterior or posterior division was stimulated, and frequently the pupils contracted and 
the animal tended to close the eyes. 
Experiment VII. 
November 18 th, 1873. — The angular gyrus of the left hemisphere of a monkey was 
exposed, and after electric irritation, causing the 
movements already described, the whole of this 
convolution, with the upper part of the superior 
temporo-sphenoidal convolution situated between 
the two limbs, was seared and destroyed with 
the galvanic cautery (see fig. 9). The left eye 
was then securely sealed up with plaster, and the 
animal left to recover from its chloroform stupor. 
A few minutes after it began to struggle a 
little, as if endeavouring to rise, but was unable 
to get on its legs. Half an hour after it sat up, 
and began to grope about cautiously, but made 
no efforts at progression. It made no sign when 
a light was approximated to its eye. It did not 
flinch when lifted up and its face brought quite 
up to the light. 
It had retained its sensation as regards hearing 
and touch, starting if a noise was made, and expressing annoyance if it was pinched. 
When placed in its cage beside two other monkeys, it clung to the bars of the cage, 
and took no notice of its companions. It would not stir from the position it assumed. 
A little later sat down in its cage, with its head covered with its hands. 
An hour having elapsed, it was taken from the cage and the left eye unbandaged. 
Immediately on this being done, it looked around, and seeing the door of the cage 
open, ran nimbly and made its way among its companions. 
* By this term, as also by the term “ sensation ” which I sometimes use, I wish to signify the fact of 
conscious discrimination of impressions as distinct from the mere sensory impressions themselves. 
Fig. 9. 
Fig. 9 represents the left hemisphere of the 
brain of the monkey. 
The shading which occupies the whole of 
the angular gyrus and the upper angle of the 
superior temporo-sphenoidal convolution indi- 
cates the extent to which the grey matter was 
cauterized in Experiment VII. 
