DE. D. EEEEIEE ON THE BEAIN OE MONKEYS. 
465 
end of the uncinate gyrus, but then leaving the inner aspect of the temporo-sphenoidal 
lobe, had ploughed off the left tubercles of the corpora quadrigemina, then penetrating 
the middle of the left optic thalamus had passed inwards and emerged at the longitudinal 
fissure on its basilar aspect. The corpus striatum was uninjured, as the wire had 
penetrated to the inside of this ganglion. 
There was no effusion into the skull, and, beyond the injury narrated, the rest of the 
brain had not been injured. The optic tract of the left side had of course been 
destroyed along with the left tubercles of the corpora quadrigemina, and the anterior 
extremity of the sinus was situated just in front of the optic commissure. 
In this the loss of sensation on the opposite side coincided with destruction of the left 
optic thalamus and the injury to the tegmentum cruris. 
The ptosis of the left eye indicated the destruction of the nucleus of the third nerve, 
situated just below the region of the lesion in the corpora quadrigemina. As the optic 
thalamus was destroyed along with part of the uncinate convolution, this experiment 
of course does not warrant any conclusion as to the effect of destruction of this convo- 
lution itself. 
As regards the optic thalamus, and the effect of its destruction, see also Exp. XIX. 
The following experiment is a repetition of the last, and was only partially successful. 
Experiment XVII. 
February 9th, 1875. — The left occipital lobe of a monkey was exposed as in last 
experiment, and hot wires were pushed through the tip of the occipital lobe in a 
direction downwards and outwards, approximately in the direction of the hippocampus 
major. There was no haemorrhage of any extent. 
The operation was completed at 3.15 p.m. The animal was already conscious before 
the wound was dressed. It was freed and laid before the fire. 
3.30 p.m. Lies by the fire breathing quietly. Pupils equal, and both eyes open. Utters 
a grunt of recognition when called to, and also begins to move its tail and right hand. 
Gets up, hut sits unsteadily, inclining to fall over on its right side. Reaction to hot 
iron distinct on both sides of the body. 
3.50 p.m. Retains sight unimpaired. Can now sit up more steadily and walk without 
falling. Took a piece of apple offered to it in its right hand and ate it. 
5 p.m. Took some tea, and ate some fruit. While sitting before the fire accidentally 
touched the bar of the grate, on which it manifested a lively sense of pain, and rubbed 
the part. The animal seems to retain all its senses and muscular power unimpaired. 
9 p.m. Continues as before. Clings with right as well as left hand to its cage when laid 
hold of. 
When offered any thing to eat, it now uses its left hand, whereas formerly it almost 
invariably employed the right. There is a distinct reaction to heat on the right side. 
February 10£/i.— 10 a.m. Remains as before. Eats and drinks heartily. Sees and 
hears perfectly. Reaction to hot iron still continues on both sides. 
MDCCCLXXV. 3 Q 
