DR. D. PERRIER ON THE BRAIN OE MONKEYS. 
475 
It has before been stated that the occipital lobes do not give any external response 
to the electric stimulus. 
Destruction of the Occipital Lobes. 
Experiment XX. 
November 21 st, 1873. — The occipital lobes were exposed on both sides in an active 
and intelligent monkey. 
By means of the galvano-cautery the upper surface of the exposed lobes was disor- 
ganized as far back as their posterior extremity, while the left was further almost 
severed from the rest of the brain by carrying the cautery perpendicularly downwards 
towards the tentorium. It was not removed, however. 
The operation was completed at 6 p.m, 
6.15 p.m. The animal sat up spontaneously, which it did in a very unsteady manner, 
and kept its head bent on the chest. Some milk was poured down its throat. Gave 
evidence of retention of sight. 
6.25 p.m. Moves about a little, looking about. Shows signs of pain and annoyance 
when its tail is pinched. Grunts discontentedly when nudged and made to move. 
8 p.m. Made to swallow some more food. When placed in the cage beside the other 
monkeys it sat with its head bent, grunting when disturbed by them, and screaming 
when they began roughly to examine its head. 
Being obliged to be absent from London for a few days, I found on my return that 
the animal had survived till the 25th. During the whole period it had maintained its 
dejected and melancholy attitude, paying no attention to its surroundings, and had 
shown no desire to eat or drink. 
After death the occipital lobes were found disorganized, while the rest of the brain 
was uninjured. The stomach and intestines were completely empty. The other viscera 
were normal. No drawing was made of the brain. 
In this case it might be supposed that the effects were merely due to the severity of 
the operation ; but a review of the foregoing experiments will serve to indicate that 
experiments involving quite as serious surgical operations were not followed by the same 
depression, the animals still retaining their appetite, and eating and drinking as 
before. 
The results as regards motion and sensation were negative ; and the only effect which 
could be noted was the general depression, and the abolition of the animal’s appetite. 
Experiment XXI. 
January 1 Qth, 1875. — The occipital lobes of a monkey were exposed on both sides, 
and the dura mater removed from both. Owing to the rupture of a venous sinus on the 
right side, cotton-wool, soaked in perchloride of iron, had to be used to stanch the 
hsemorrhage, and there was reason to fear that it had in some degree injured the brain. 
At 4 p.m. the left occipital lobe was separated from the hemisphere by means of 
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