696 DR JAMES W. DAWSON ON 



rounded by numerous satellite cells. The blood-vessels had, to a very striking extent, their 

 adventitial sheaths dilated, and in areas passing over from the base of the radiations into 

 the deeper cortical layers the short and long medullary vessels, with widened adventitia, 

 could be traced passing out from the area at both limits. In the areas in the central white 

 matter the vessels often showed clearly the gradual disappearance of the cell content of the 

 vessel wall — -after the removal of the fat granule cells — and the very slow fusion of the 

 previously separated connective-tissue fibrils of the adventitia into a " hyaline " homo- 

 geneous layer (cf. figs. 14-15). 



Topographical Distribution. 



Spinal Cord. — Cervical Enlargement (figs. 104-108). — At C5 the two most marked areas 

 occur in the form of triangles : the one has as its base a line drawn outwards from the pos- 

 terior commissure and its apex is the tip of the anterior fissure. The other has a curved 

 base in one postero-lateral periphery of the cord : its apex is continuous with the lateral 

 angle of the other triangle in the centre of the grey matter ; and it blocks out the whole 

 of the antero-lateral column, the posterior horn, and part of the adjacent posterior column. 

 A bowl-shaped area is present in the posterior columns, with its base on the surface of the 

 cord, and diffusely-staining fibres extend antero -laterally from it. A narrow zone clearly 

 outlines the other posterior horn, and two smaller areas appear in the lateral column of this 

 side. At C6 there is almost a complete transection of the cord : five separate groups of 

 normally-staining fibres remain — two of these lie on one side at the anterior and pos- 

 terior root zones ; a third, larger, area near the opposite posterior root zone and anterior 

 from it ; and the others are isolated fibres near to the central canal and the para-median 

 septum on the same side. At C7 one large area involves the whole of one-half of the cord, 

 with the exception of the tissue anterior to an undulating line drawn outwards from the 

 base of the anterior fissure : it passes into the grey matter and posterior columns of the 

 opposite side — leaving a small isolated group of fibres close*to the posterior root-entry zone. 

 The borders of the anterior fissure are also involved, and this sclerosis is continuous with 

 the larger area. On the opposite side a semicircular marginal area is present, opposite 

 the lateral aspect of the anterior horn, together with a smaller patch directly anterior to 

 the horn. At C8 the anterior half of the cord stains well : the postero-lateral columns on 

 one side are completely sclerosed, with the exception of isolated fibres in the posterior root- 

 entry zone and in the column of Goll : and on the other side the postero-lateral columns, 

 with the exception of its anterior portion and a band of fibres in the column of Burdach — 

 the anterior horn escapes on this side, while on the opposite side only the antero-mesial 

 portion is free. 



Dorsal Region (figs. 108-111). — In Dl the whole of one-half of the cord is again involved, 

 with the exception of a triangular area which lies in the columns of Burdach, immediately 

 adjoining, and including, part of the posterior horn. On the opposite side the sclerosis 

 involves the cord posterior to a line drawn outwards from the central canal, but into this 

 sclerotic tissue a pointed process of normally-myelinated grey matter passes, so that the 

 normal antero-lateral portion has one sharply concave and one curved border, botli clearly 

 outlined. In D3 the sclerotic area is in the form of a right-angled triangle — one side being 

 formed by a line in the opposite column of Goll parallel to the posterior median fissure, 

 the other side by a line drawn outwards from the base of the anterior fissure, and the base 

 being formed by the curved circumference of the cord. A number of smaller areas are 

 also present : one lies on the surface in the centre of the anterior root zone ; a second, marginal, 

 area in the opposite side, half-way down the anterior fissure ; a third in the apex of the 

 posterior horn ; and a fourth in the fibres immediately ventral to this horn. At D4 this 

 latter area has become an elongated oval, and is continued by faintly-staining fibres as far 



