THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 62 1 



was densely sclerosed and was surrounded by a broad, early transitional zone which 

 above and below had a narrow wedge shape ; and in others, as the area in the 

 posterior columns was left behind, further serial sections showed the involvement of 

 the posterior horns, the commissures and lateral tracts in one extensive area. The 

 innumerable variations can thus only be hinted at, but one further feature must be 

 mentioned. Such long stretches — extending sometimes over two upper dorsal 

 segments for instance — showed that definite areas in the same columns were united 

 by faintly-staining tissue, which sometimes showed Marchi degeneration, or such 

 an appearance was continued onwards, ascending or descending, from definite 

 sclerotic tissue. The illustrations sufficiently indicate that the cervical cord and 

 dorsal cord were more frequently and more extensively involved than the lumbar 

 and sacral cords. 



In the medulla oblongata, pons, cerebral peduncles and cerebellum, the same two 

 primary forms were present with numerous variations. Sub-pial areas were fre- 

 quently wedge-shaped, and these within the substance of the tissue round or oval, 

 with the long diameter in frontal or sagittal section. Here, too, the confluence of 

 the areas was marked. The cranial nuclei shared in the general extension from the 

 floor of the IVth ventricle — an extension which usually took place in isolated 

 broad processes which subsequently fused with one another. The almost complete 

 symmetry of the involvement is apparent in figs. 143 and 144, and in these areas 

 again the islets of normal fibres left showed a remarkable parallelism. The extension 

 of the sclerosis on the floor of the IVth ventricle passed laterally and, from the 

 angles of the ventricle, inwards to involve the structures which at various levels are 

 found in this region. The figures and the detailed topographical description 

 sufficiently indicate the distribution. The lateral extension to the roof of the 

 IVth ventricle involved the white matter of the cerebellum, the hilum of the 

 dentate nucleus, the nuclei of the roof, and often the whole of the folia forming the 

 vermis and nodules (of. figs. 76-82). 



The peri-ventricular areas showed also numerous primary, wedge-shaped areas 

 with broad base to the ventricle, and extensions into the adjoining tissue in the 

 form of finger-like processes or ampullae, in each of which a central vessel could 

 usually be found. • All these areas were often united by tissue staining faintly in 

 Weigert sections. Around the posterior and anterior horns of the lateral ventricle 

 the sclerosis assumed the form of a hood, the apex of which was continued in 

 the direction of the frontal and occipital poles by a series of rounded or oval 

 small areas. 



In the medullary rays numerous submiliary foci were present, round or oval, 

 with the long diameter parallel to the course of the fibres. The areas in the 

 medullary rays were often united by tissue in an earlier stage of degeneration. 

 This gave a striped appearance even macroscopically. The peri-ventricular sclerosis 

 of the descending horn of the lateral ventricle in almost every instance extended 



TRANS. ROY. SOC. EDIN., VOL. L, PART III (NO. 18). 87 



