468 
DE. D. FEEEIEE ON THE BE A IN OF MONKEYS. 
Experiment XVIII. 
March 2nd , 1875. — A large monkey of the baboon type was chosen for this experi- 
ment. As it seemed to be usually left-handed, the right hemisphere was operated on. 
The right occipital lobe having been exposed, hot irons were passed through the 
posterior aspect of the lobe in the direction of the hippocampal gyrus. 
There was no haemorrhage of any moment. 
The operation was completed at 3.15 p.m. 
3.20 P.M. The animal lies by the fire, having recovered consciousness, and moves its 
limbs, but has not yet attempted to get up. 
3.25 p.m. When moved it opened its eyes, whence it was concluded that the crus 
cerebri had not been injured. 
While lying by the fire scratched its right leg with its right hand. Does not move 
its left arm or left leg, whether laid on its right or left side. 
3.35 p.m. There is no reaction to a hot iron on the left side. The same stimulus, 
causes active manifestation of pain and rubbing when applied to the right side. 
3.45 p.m. Begins to sit up and look about. 
Moves only the limbs of the right side, and in sitting up occasionally falls over 
on its back. 
The test of the hot iron was again applied. 
On the right side the slightest touch caused active reaction, and caused the animal to 
rub the part touched. Applied to the left foot, the iron was kept in contact several 
seconds without causing the slightest reaction, but when kept up longer a slight 
retraction was caused. The same result was obtained on the left hand and the 
right ear. 
Pinching of the right hand and right foot caused violent reaction and slight cry. No 
effect followed the strongest pinching of the left hand and foot. The left ear gave 
slight reaction to pinching. 
4 p.m. The animal is sitting up and looking about. Grunts when called to. Occa- 
sionally falls over. Recovers itself by the aid of its right limbs. It can draw the legs 
together, but the left foot is generally allowed to straddle outwards and rest on the 
internal malleolus. The left arm is kept motionless in a semiflexed condition. Mus- 
cular resistance continues. 
4.15 p.m. When offered food it took it with the right hand, and raised it to its mouth. 
Occasionally moves its left arm and leg while sitting still, but does not use them to 
grasp or in progression. 
The reaction to the hot iron is still persistent on the right, but gone on the left side. 
The animal was occasionally seen to give a jerk of its head and grind its teeth, which 
I attributed to some irritation of the fifth nerves, probably caused by inflammation of 
the dura mater in the neighbourhood of the Gasserian ganglion, set up by contact of 
the cautery. 
