598 DR JAMES W. DAWSON ON 



sclerosis. In the layer of stellate cells (figs. 391, 394) also there are the same 

 changes with a more marked disappearance of the ganglion cell bodies, leaving only 

 nuclei surrounded here and there by nests of cells. 



3. Peri-ventricular Sclerosis. 



This special localisation, noted by Charcot, Borst, Strahuber, Westphal, and 

 others, has been emphasised as the dominant feature in the cases reported by 

 Lhermitte and Guccione, Merle and Pastine, and also by Schob. It is of special 

 interest in relation to the pathogenesis of disseminated sclerosis, and at once raises 

 the question whether the development of the peri-ependymal areas may not be 

 conditioned by the presence of the causal agent in the cerebro-spinal fluid itself. In 

 horizontal sections through the cerebral hemispheres, there was frequently found a 

 sclerosis which, macroscopically, seemed limited to the walls of the ventricles (figs. 

 200, 201), and very numerous sections at various levels were studied to determine 

 the exact limits of this alteration, in what it consisted, and whether the apparently 

 isolated areas in the adjoining grey nuclei or white matter were really offshoots from 

 the areas on the ventricular surface. In all the cases which showed a peri-ventricular 

 sclerosis, this was much more marked around the horns, especially the posterior horn 

 (figs. 23, 24), but sections cut at lower levels, e.g. through the temporo-sphenoidal 

 lobe (fig. 29), horizontally or sagittally, showed the almost equally marked involve- 

 ment of the descending horns on both sides, and sections of the hemispheres cut at 

 levels immediately above the corpus callosum showed large round isolated areas in 

 the central white matter, some of which, in serial section, proved their connection 

 with the sclerosis of the roof of the lateral ventricle (figs. 25, 26). It is thus seen 

 that not only were the walls of the ventricle involved, to a varying degree, through- 

 out their whole surface — lateral walls, horns, floor and roof, — but that this sclerosis 

 extended inwards from the ventricular surfaces, forming a zone from one-half a 

 centimetre to 1 centimetre broad in the adjoining grey nuclei or white matter. 

 Further, that from this zone at numerous points processes — sometimes finger-like, 

 sometimes cup-shaped — passed deeper into the surrounding tissue. Such areas 

 appeared naturally, in some sections, isolated from the peri-ventricular sclerosis or 

 attached to this by a narrow neck, in which often lay a central vessel with walls 

 changed according to the degree of sclerosis reached. 



Horizontal sections through the hemispheres at Pierre Marie's coupe d'e'lection, or 

 immediately above or below this level (figs. 23, 24 ; 70-73 ; 93-96), showed that the 

 occipital horn was surrounded by a hood of changed tissue, macroscopically greyish- 

 white and gelatinous (fig. 200), or of a whitish-yellow colour and softer consistence. 

 From the point of this hood the sclerosis is prolonged in a series of small elongated 

 or rounded areas towards the posterior extremity of the occipital lobe, involving the 

 optic radiations, the inferior longitudinal fasciculus, and the tapetum at several 

 points, and in some cases involving the medullary rays and cortex of the convolu- 



