THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 599 



tions of the calcarine fissure. The sclerosis of the anterior horns is less marked, but 

 is also prolonged in the direction of the frontal lobe, and laterally involves the 

 lenticular nucleus and the cortico-pontine fibres. Between these two horns the 

 thickness of the sclerotic tissue varies greatly at individual levels — sometimes the 

 lateral walls of the ventricle are scarcely involved, again there may be a sinuous 

 narrow margin along its whole extent, and again the outer border at parts may be 

 half a centimetre broad, with well-marked processes extending into the grey nuclei 

 and adjoining white matter. The fornix and the corpus callosum, on the ventricular 

 surface both of the splenium and genu, were also involved, and isolated areas were 

 also found in both, which seemed to have no connection with the ventricular border. 



Horizontal sections near the roof of the ventricle usually showed an involvement 

 of the entire surface extent of the ventricular walls, with well-marked pouches 

 passing inwards into the corpus callosum on the one side and the central white 

 matter on the other (fig. 26), and also passing upwards. One such area above the 

 roof of the ventricle (fig. 25), three-quarters of a centimetre in diameter, was traced 

 not only to its connection with the roof sclerosis, but upwards till it gradually 

 diminished and broke up into a series of smaller areas. In this large area there 

 was no one central vessel, but a large number of dilated vessels — arteries, veins 

 and capillaries — with their walls all filled with fat granule cells. The tissue was very 

 soft and fell out in the large celloidin section ; in the bichromate it had appeared 

 chrome-yellow in colour and much lighter than the surrounding white matter. 



Horizontal sections through the temporo-sphenoidal lobe (fig. 29) on both sides 

 showed that the sclerosis of the descending horn was very marked, and below the 

 floor of the ventricle it had extended to involve almost the whole of the adjoining 

 white matter, reached into almost every one of the medullary rays passing off from 

 this, and that there were also numerous areas in the cortical grey matter in close 

 relation to the affected medullary rays. Sagittal sections through the temporo- 

 sphenoidal lobe in other cases gave a very instructive picture of the extension 

 outwards of the ring of peri- ventricular sclerosis into each medullary ray and of the 

 very frequent involvement of the white matter of the hippocampal convolution, of 

 the fimbria, and of the gyrus dentatus. 



The ventricles, in most of the cases, were not dilated : their walls also were 

 smooth, and presented neither granulations nor glandular indentations. In one case 

 (figs. 70-73) the lateral ventricles were very dilated, and the outline of the sclerosis 

 between anterior and posterior horns was so irregular and passed on both sides so 

 deeply into the optic thalamus, in which were also numerous apparently isolated 

 areas, that the substance of the optic thalami, the internal capsules, the lenticular 

 nuclei and external capsules presented a moth-eaten appearance. In one case 

 especially (fig. 201) the numerous veins in the sub-ependymal glious tissue, especially 

 near the posterior horns, were macroscopically outlined on the ventricular surface 

 by a gelatinous, deeply-stained zone, and, microscopically, it was found that this 



