THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 737 



Fig. 350. Stage of so-called " fat granule cell myelitis." 



Fig. 351. Advancing glia fibril formation. 



Fig. 352. Fat granule cells collected in the adventitial sheaths of the vessels and gradually being drained 

 away from the area. 



Fig. 353. Stage of advanced sclerosis ; no fat granule cells but finely granular glia and retained axis 

 cylinders. 



Figs. 355-356. Same evolution under low power. Small area in anterior third of posterior columns. 

 Fig. 355, stage of advanced glia fibril formation. Van Gieson's stain. x 70. Fig. 356, stage of advanced 

 sclerosis. Van Gieson's stain. x 50. 



Fig. 357. H.P. of transition zone (t) of area similar to that in previous figure (cf. fig. 12). 



Figs. 358-360. Variations in the final glia picture of the above evolution ; transverse sections of the 

 posterior columns of the cord. 



Fig. 358. Dense sclerotic tissue containing a few fat granule cells and numerous enlarged glia'cells. 

 Van Gieson's stain. x 200. 



Fig. 359. Showing glia whorls and irregular glia fibril formation. Van Gieson's stain. x 50. 



Fig. 360. Central " Kielstreifen," with numerous large glia cells and swollen axis cylinders in the dense 

 sclerotic tissue on either side. 



Plate LXXI. 



Figs. 361-366. Evolution of a sclerotic area (fig. 364) in the cerebral white matter, through a stage of 

 fat granule cell formation; nerve fibres cut mostly transversely (pp. 586-588). Cf. figs. 5 and 6. a = glia 

 cells; 6 = glia fibrils; c = fat granule cells; (2 = axis cylinders; e = blood-vessels. Heidenhain's iron- 

 haematoxylin stain. 



Fig. 361, x 40; cf. fig. 5. Small "early" area with e = central blood-vessel; t = transitional nucleated 

 zone. 



Fig. 362, x 60. Stage of commencing glia fibril formation and fat granule cell formation ; /'=fig. 365. 



Fig. 363, x 60. Stage of advancing glia fibril formation ; /'=fig. 366. 



Fig. 364, x 60. Stage of complete sclerosis — a dense tissue with very fine meshes. 



Fig. 365, x 300. H.P. of fig. 362 (/). 



Fig. 366, x 300. H.P. of fig. 363 (/). 



Figs. 367-369. Variations in the density of the final glia network. Iron-hsematoxylin. Figs. 367, x 150, 

 open network with a few persistent axis cylinders; figs. 368, x 150, denser network, especially around 

 the capillaries ; fig. 369, x 80, numerous glia nuclei which form the nodal points from which radiate 

 glia fibrils. 



Figs. 370-372. Evolution of a sclerotic area (fig. 372) in the cerebral white matter (medullary ray) ; 

 nerve fibres cut longitudinally (p. 588). Heidenhain's iron-hsematoxylin. x 200. Note the persistence 

 of the axis cylinders as swollen, homogeneous lines. 



Plate LXXII. 



Figs. 373-378. Sclerotic areas in special situations. Iron-hsematoxylin. Fig. 373, x 70, in the middle 

 cerebellar peduncle ; fig. 374, x 150, ditto, showing a more advanced glia fibril formation ; fig. 375, x 200, 

 in the hilum of the dentate nucleus; fig. 376, x 38, "early" peri-ventricular area; fig. 377, x 200, H.P. 

 of previous figure; fig. 378, x 150, area cutting across a medullary core of a cerebellar folia. 



Figs. 379-384. Types of glia cell changes; cf. figs. 391-396. Iron-haematoxylin. Fig. 379, x 500, in 

 the posterior column of the spitial cord ; rows of large, frequently multi-nucleated, protoplasmic glia cells ; 

 fig. 380, x 600, in the cerebral white matter; protoplasmic potential fibril-forming cells; fig. 381, x 200, 

 in the cortex ; nests of small glia cells (a) surrounding the ghosts of ganglion cells ; also (b) protoplasmic 

 glia cells. 



Figs. 382-384. Evolution of glia fibrils from large protoplasmic glia cells. x 600. Note the definition 

 of the borders of the protoplasmic procpsses (fig. 382), which can be followed throughout the concave border 

 of two adjoining processes (fig. 383), and that the general outline of the fibrils corresponds at first to the 



