626 DR JAMES W. DAWSON ON 



nuclear areas on the floor of the IVth ventricle were markedly involved and many 

 of the cells filled with a dark brown pigment. Nearly all the cranial nerve roots, 

 on both sides, entered into demyelinated tissue. The areas have characters similar 

 to those of the cord, only a few showing any definite central condensation. On the 

 other hand, large irregular areas were found which showed a complete demyelination 

 without any marked glia cell proliferation or blood-vessel change or alteration in the 

 axis cylinders either in number or calibre. A very beautiful illustration of such an 

 area is seen in figs. 16, 17, and 421, in which can be seen the sharp, irregular outline 

 of the demyelinated tissue and the continuation onwards of the axis cylinders, which 

 intersect in the median raph6. These axis cylinders are tortuous and delicate, and 

 their density, in Bielschowsky preparations, is the same as in normal conditions. 

 The blood-vessels here are dilated and their walls also impregnated by the silver. 

 The distribution of the areas in relation to the floor and walls of the IVth ventricle 

 and to the hilum of the dentate nucleus will later be referred to, but attention 

 must here be drawn to the prominent involvement of numerous folise in the 

 cerebellum and of the almost symmetrical affection of the flocculi (figs. 27 and 28) 

 and of their peduncles. 



The peri-ventricular sclerosis gave the impression of being the result of the fusion 

 of sub-ependymal areas, and in individual sections such primary, wedge-shaped areas, 

 with base to the ventricle, could be recognised. Around the lateral ventricles and 

 their horns, on all sides, large isolated areas could be traced in the white matter : 

 their connection with the peri-ventricular sclerosis, especially in the areas above the 

 roof of the lateral ventricles, could frequently be definitely proved. Numerous fat 

 granule cells were found distributed throughout the whole peri-ventricular tissue, 

 and in the walls of the sub-ependymal veins. The ventricles were not dilated, their 

 walls were smooth, and there was no change in the ependymal epithelium. 



The cortical areas were not very numerous compared to those found in one or two 

 other cases, and there was an almost complete absence of the irregular demyelination 

 of the superficial layers of the cortex. The contrast between the fat granule cells 

 of the grey matter and those of the white matter was often well brought out 

 (cf. figs. 69 and 396). Bielschowsky preparations of the cortical areas showed 

 numerous axis cylinders. 



The optic nerves were extensively involved : the right was wholly demyelinated 

 and showed a marked thickening of the connective tissue and glia trabecule (fig. 444). 

 In the left nerve only one narrow strand of myelinated fibres could be found, but its 

 whole length showed rows of fat granule cells (fig. 65). 



2. Topographical Distribution in Weigert Sections. 

 Spinal Cord. 



Cervical region (figs. 48-54). — At the upper part of the cervical cord only a 

 deficient staining of the myelin was found, involving the anterolateral column of 



