THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 727 



stain. x 350. « = glia nuclei; b = blood-vessel ; c = fat granule cell; rf = cell containing blood pigment; 

 e = lymphocyte-like cells; /= plasma cell ; f/ = glia tissue ; h = connective-tissue cell. 



Fig. 13. A transition vessel with its adventitial sheath filled with fat granule cells; numerous similar 

 cells and enlarged glia cells in the surrounding tissue. 



Fig. 14. A larger vessel (cf. fig. 439), during the stage of advancing sclerosis, to show the cell tontent 

 of the adventitia after the removal of the fat grannie cells. 



Fig. 15. Small artery in an area of advanced sclerosis. Note the commencing " hyaline" fusion of the 

 media and adventitia ; the outer layers of the adventitia and the layers of the peri-vascular glia are still 

 dilated and have an increased cell content. At a later stage the glia sclerosis immediately surrounds the 

 dense, homogeneous vessel wall, which then shows few or no cell elements. 



Plate XLVII. 



Figs. 16-17. Persistence of axis cylinders across a demyelinated area in the pons. Cf. figs. 289 and 

 421. Bielschowsky-Williamson silver impregnation method. Fig. 16, x 20; fig. 17, x 90. a = line of 

 transition between myelinated and demyelinated fibres; b = median raphe where axis cylinders intersect ; 

 x = shown in fig. 17, under high power. 



Figs. 18-20. Stages in the demyelination of an area and in the evolution of the fat granule cell. 

 Frozen sections cut in the longitudinal direction of the nerve fibres. Scharlach R. x 300. a = small glia 

 nuclei; c = fat granule cell; 5 = transition forms between a and b ; d = nerve fibre; e = blood-vessel ; 

 /= proliferated glia nuclei. 



Fig. 18. Longitudinal nerve fibres immediately adjoining a demyelinated area. Note the cells contain- 

 ing fat granules. 



Fig. 19. Structural elements in the transition zone of an early area. Note the longitudinal myelinated 

 nerve fibres passing into the area, the rows of enlarged glia cells, and the numerous fat granule cells in all 

 stages of their formation. The first fat granules are contained in the protoplasm adjoining the poles of the 

 nucleus and as they increase in amount the cell becomes round. 



Fig. 20. Capillary, in a demyelinated area, completely surrounded by a layer of fat granule cells. 

 Adventitial sheath not brought out in this stain. 



Figs. 21-22. Glia changes in a completely demyelinated area in the cortex (p. 595). Cf. figs. 

 301-396. Ford-Robertson's methyl-violet stain. x 500. a = proliferated glia cells with protoplasm and 

 processes differentiated into fibrils ; b = capillaries with glia fibrils attached to their outer membrane ; 

 c = ganglion cells ; d= small glia cells forming nests around the remains of ganglion cells; e = degenerated 

 ganglion cells ; /= retained axis cylinders. Note that the normal cy to-arch itecture of the tissue is preserved. 



Fig. 21. Deepest (polymorphous) layer of the cortex. 



Fig. 22. Layer of the deep pyramids. 



Plates XLVIII, XL IX, L (Case I). 



Figs. 23-63. Sections of brain and spinal cord. Kulschitsky-Pal myelin sheath stain with picro-fuchsin. 

 Figs. 64-69. Sections to show the prevailing type of area present. Marchi method. 



Figs. 23-24. Complete horizontal sections through the cerebral hemispheres at the lower part of the 

 basal ganglia (p. 631). a = peri-ventricular sclerosis around the posterior horns of the lateral ventricles, 

 whence the sclerosis is continued backwards towards the calcarine fissure ; b = the involvement of the splenium 

 of the corpus callosum ; c = area in the left optic thalamus; d = areas in the right and left claustrum 

 extending to involve the convolutions of the island of Reil — small areas are present also in the anterior and 

 posterior limbs of the internal capsules and in the right and left putamen ; e = oval area in the medullary 

 ray and grey matter of the anterior part of the left frontal operculum (cf. fig. 284) ; /=two small areas in 

 the right frontal operculum; g = several areas in the convolutions of the occipital lobe in both sides, 

 especially around the calcarine fissure. 



Fig. 26. Level of the roof of the right lateral ventricle, a = involvement of the outer wall and posterior 

 tip of the ventricle; h = large areas in the adjoining white mattef, especially towards the occipital lobe; 

 c = nrea in the medullary ray of the post-Rolandic gyrus in the precuneus. 



