FIBRES OF THE INTERNAL CAPSULE OF THE BONNET MONKEY. 
53 
upper end next the longitudinal fissure, and except also its lower end, amounting 
nearly to one-third of the length of the whole gyrus ; also the posterior third of the 
upper division of the anterior portion of the frontal lobe. 
Further, the ascending parietal gyrus was removed, except 5 mm. at the upper and 
6 mm. at the lower end, and a small piece of the parietal lobule; and, in addition, 
rather more than half of the ascending limb of the angular and the supra-marginal 
gyri. 
The effects of this lesion were as follows :—- 
Internal capsule .—Sections of the internal capsule showed in its “central part” a 
number of bundles mostly degenerated, which were not all closely packed together, but 
were somewhat scattered, being here and there separated by others which presented a 
normal appearance. In many of the flattened degenerated bundles there was a thin 
layer forming a sort of cortical stratum, in which the fibres appear normal. 
In a section of the crus cerebri a patch of degeneration was found to be situated in 
the central part of the crusta, localised near the ventral border as an oval area tapering 
mesially. 
Ferrier'^ found in the Monkey that removal of the prsefroutal regions was 
followed by degeneration of “the lowermost and most internal” fibres in “the 
transverse sections of the internal capsule and the most median bundles of the foot 
of the crus cerebri.” 
Examination of the photographs of the brains shews that in each case the cortical 
areas for turning of the head and eyes were encroached upon by the lesion. 
Man. 
TurckI in his original memoir showed that in cases of long-standing hemiplegia 
the hinder and upper part of the capsule was degenerated, and also the middle 
segment of the crus. 
Flechsig| observed in a new-born infant, 44 cm. long, that the internal capsule 
was white only between the thalamus and lenticular nucleus. At the same time the 
lamime medullares of the lenticular nucleus as well as the fibres surrounding their 
posterior extremities were brighter than the neighbouring parts. In tlie crus cerebri 
there was seen on the lower and outer side a sharply bounded bright band 3 mm. 
broad (pyramidal tract) which was continued up into the internal capsule close to the 
innermost zone of the lenticular nucleus. In a further paper § he shows reason for 
* “A record of experiments on the effects of Lesion of different regions of the Cerebral Hemispheres,” 
with Gerald Yeo, ‘Phil. Trans.,’ 1884.—Experiments 22 and 23, p. 528. 
f ‘ Sitznngsberichte der mathematisch-naturwissenschaftlichen Classe der Kaiserlichen Akademie der 
Wissenschaften,’ vol. 6, Wien, 1851, p. 300. 
t ‘ Die Leitungsbahnen im Gehirn und Riickeninark des Menschen,’ Leipzig, 1876, pp. 27, 28, Taf. II., 
fig. 3. 
§ ‘ Archiv fiir Anat. und Phys. (Anat. Abth.),’ 1881, p. 12. 
