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central convolution (Fig. 1, L. C.). Its upper extremity was in the 
level of the genu of the pre-central sulcus, and it extended downward and 
backward 5 mm. about midway between the perpendicular ramus of that 
sulcus and the fissure of Rolando. There was no evidence of disturbed 
function and at the end of 10 days the animal was killed with chloroform, 
the brain removed, hardened, stained, and cut in horizontal sections like 
the others. Examination of the hardened brain showed that the lesion 
was much less extensive than in the preceding experiment, the resulting 
hemorrhage much less, and the injury to the tissues in consequence of 
hemorrhage much less. The wound nowhere reached more than two- 
thirds of the distance across the hemisphere toward the middle line, and, 
in the levels corresponding to the external wound, the lesion was almost 
entirely cortical. Owing to the oblique direction in which the pre-central 
sulcus sinks into the hemisphere in this level (Fig. 12), at a depth of 7 
mm. (half the depth of the wound in this level) the knife reached this 
sulcus and separated a triangular portion of cortex from the pre-central 
convolution, and the most mesial extremity of the cut barely nicked the 
edge of the corona radiata. In lower levels, where the breadth of the 
hemisphere is greater and the depth of the cortex proportionately less, 
owing to the less acute angle of section, the lesion was less purely cortical 
and deeper tissues were involved. Below the level of the external wound 
the knife penetrated farther and farther into the corona radiata and at 
the point of deepest penetration the uppermost fibers entering the anterior 
segment of the internal capsule were completely severed (Fig. 13). This, 
however, is true of only the uppermost levels, for before the fissure of 
Rolando disappears from the section the incision falls short of the outer- 
most edge of the anterior segment. Below this point the knife wounded 
the anterior portion of the putamen, and still lower severed the anterior 
portion of the claustrum from the rest of the nucleus, at the same time, 
of course, cutting all the longitudinal fibers in that portion of the cap- 
sula externa and extrema. Near the base of the brain the wound was 
again purely cortical, involving the anterior portion of the island and the 
operculum. At no point was that portion of the cortex injured which I 
have shown to contain giant cells." A small clot had formed within the 
wound, damaging a small area of corona radiata, 2 x 4 mm. in extent, but 
there were no traces of hemorrhage either from the wound on the external 
surface of the hemisphere or into the fossa of Sylvius. 
In the upper levels of the lesion there was considerable degeneration 
1A Study of the Location and Arrangement of the Giant Cells in the Cortex 
of the Monkey, The American Journal of Anatomy, Vol. IV, No. 4. 
