484 
DR. D. FERRIER ON THE BRAIN OF MONKEYS. 
This animal exhibited less of that dejection and depression which characterized the 
other animals similarly operated on. 
It is difficult to single out any one positive result of the destruction of this part of 
the brain, except the remarkable aversion to food which was observed almost invariably. 
This may be regarded as due to the constitutional disturbance consequent on such severe 
mutilation ; but if so, it will be difficult to account for the fact that equally severe 
mutilation of the frontal lobes and other parts of the brain caused little or no impair- 
ment of the appetite for food. 
I am disposed to think, therefore, that the aversion to food stands in causal relation 
to the destruction of the occipital lobes as such, and that these lobes are somehow related 
to the systemic sensations. The other animals did not live long enough to decide as to 
whether this condition should remain permanent ; but in experiment XXIV. the animal, 
otherwise exceptional, after remaining without food for a period of five days, again 
recovered its appetite and continued to eat as before. 
Thirst did not seem to have been affected to the same extent as the appetite for food. 
If the systemic sensation of hunger has its seat in the occipital lobes, it is difficult to 
account for the restoration of this appetite after these lobes have been removed. Yet 
it is possible that compensation may have occurred by association with other senses, such 
as of taste and smell. This is offered as a possible explanation ; but it must be admitted 
that neither the electrical irritation of the occipital lobes nor their destruction suffice 
to indicate clearly the functions which these lobes perform. 
It would appear from experiment XXIV. that their destruction does not abolish the 
sexual appetite. The exhibition of this appetite may perhaps have been due to irrita- 
tion of some centre in proximity to the seat of lesion. Some interesting speculations 
might be made with reference to these results ; but as my object in this paper has been 
to restrict myself to conclusions directly deducible from my experiments, to enter on such 
would be foreign to the subject. 
The following experiment is interesting, and one perhaps not often capable of repetition. 
Conjoint removal of Frontal and Occipital Lobes. 
Experiment XX Y. 
April 10 th, 1875. — The monkey which had had its occipital lobes removed on 
March 18th (exp. XXIV.), i. e. twenty-three days previously, and which had apparently 
quite recovered, was placed under the influence of chloroform, and the frontal lobes 
removed on both sides by a line approximately traversing the anterior extremity of the 
supero-frontal sulcus. 
The operation was completed at 12 noon. 
The animal had regained consciousness before the wound had been quite dressed. 
12.10 p.m. On being let loose and placed on the floor, it sat up and began to move 
about in a tottering manner. When it shook itself it fell over on its side. 
12.20 p.m. Is sitting up somewhat unsteadily and gnawing at whatever comes within 
