1907.] Localisation of Function in the Lemur’s Brain. 143 
side. The extirpated portion was principally the area for the upper limb. Paralysis of 
the opposite side was marked immediately after the operation, but eventually passed off 
in the way described in the experiment on Lemur 4. The animal was killed 14 days 
after the operation. 3 
Lemur 8. Lemur catta.—The leg area was removed on the right side. A good deal of 
hemorrhage occurred during the operation from the longitudinal sinus, a large branch of 
which was injured and had to be tied. The animal, nevertheless, made a good recovery, 
and paralysis of the leg had largely disappeared by the time the animal was killed, 
14 days later. 
Lemur 9. Lemur catta.—Here the operation was limited to removal of the excitable 
(mainly ear, eye, and face region) area on the outer side of the lateral sulcus and sulcus 
rectus in the right hemisphere. No paralysis was noticeable ; indeed, after recovery 
from the anesthetic, the animal was climbing about the room, and eating fruit heartily 
within an hour of the operation. It was killed 12 days later. 
It will be noticed that the last three operations form a series in which the 
arm area, the leg area, and the head and face area (characterised by the small 
Betz cells) were respectively removed. We present, in the accompanying 
plates, diagrams of the degeneration tracts, selecting, of course, only a few 
important regions from the large number of sections which were made. It 
will be seen that, although the lesions were not absolutely limited to arm, 
leg, and face areas respectively, yet from our knowledge, derived from stimula- 
tion, we were able fairly accurately to perform the operations we have 
indicated. 
In each case the large drawings which come first are those of the brain, 
drawn on a somewhat smaller scale than the others. This shows the position 
of the lesion, and also the degenerated fibres (indicated by black dots and 
lines), passing in three directions: (1) to the internal capsule; (2) to the 
opposite hemisphere by the corpus callosum; and (3) to neighbouring convo- 
lutions by association fibres. The smaller drawings show the degenerated 
tracts in lower portions of the central nervous system.. 
Histological Kxamination. 
The brains and spinal cords were placed in Miiller’s fluid for three weeks ; 
appropriate slices 3 to 4 mm. in thickness were then placed in Marchi’s 
fluid for 14 days, the fluid being changed several times. After imbedding in 
celloidin, sections were then prepared. 
The Resulting Degeneration —In all cases there was: (1) A heavy degenera- 
tion of the fibres of the internal capsule on the side of the lesion, which could 
be traced to the crusta of the pedunculus cerebri. (2) A degeneration much 
less marked—with the degenerated fibres not so coarse—of the corpus 
callosum; most of these enter the radiating fibres of the opposite hemi- 
sphere, and-pass especially to that portion which corresponds to the region of 
VOL, LXXX.—B. M 
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