OF THE GYRUS MARGINALIS AND GYRUS FORNICATUS IN MONKFYS. 
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Case 4.— No. 19 of First Series. 
Lesion. —Excision of both marginal convolutions : on the left side for the posterior 
three-fourths of its length, on the right side to a rather less extent. 
Frontal sections through the brain show that that part of the gyrus bordering the 
calloso-marginal fissure, and clipping down into it, was but little injured ; the upper 
border also was but little injured (see ‘Phil. Trans.,’ B, 1888, Plate 2, figs. 19R 
and 19l). 
Result. —Almost complete paralysis of the leg and trunk muscles, but there is some 
ability to move, especially to flex, the legs, particularly the left leg. 
This animal died on the ninth day after the operation. 
Degenerations Observed. 
No degeneration could be seen with the naked eye. 
Microscopic. Pons. —A few degenerated fibres are to be seen in the pyramidal 
bundles of both sides. 
Medulla. —Scattered degeneration can be seen in the pyramids on both sides, more 
distinctly than in the pons. 
Spined Cord. Cervical Enlargement. —Degenerated fibres can be seen on both 
sides scattered about the crossed pyramidal tracts, chiefly occupying the part which 
borders on the direct cerebellar tract, and extending outwards and forwards from the 
apex of the posterior cornu. 
Dorsed Region. —The patch of degeneration is more concentrated, although smaller 
in extent. In the lower dorsal region especially it lies closer to the circumference of 
the cord. It is more marked on the right than on the left side. 
Lumbar Region. —In the lumbar region the degeneration can stiU be seen on both 
sides, occupying the angles between the posterior root and the circumference. 
The degeneration consists of swollen fibres with axis cylinders in various stages of 
breaking down. 
Case 5.—Ah), 'll of First Series. 
Lesion. —Pemoval of the posterior three-fourths of both marginal gyri at one 
operation. Frontal sections through the brain show that the removal was complete 
except along the calloso-marginal fissure (see ‘Phil. Trans.,’ B, 1888, Plate 3, figs. 21a 
to 21 d). 
Result. —Paralysis of the trunk and legs. 
This animal died on the twenty-seventh day after the operation. 
Degenerations Observed. 
There was a slightly marked appearance of degeneration to be seen with the naked 
eye in both crossed pyramidal tracts all down the cord. 
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