THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 729 



{af. tigs. 49 and 59). Note further the complete demyelination at the lower dorsal (fig. 58) and lower sacral 

 segments (fig. 63), and the complete myelination of the nerve roots of the cauda equina (figs. 62 and 63 ; 

 cf. figs. 452 and 453). 



Figs. 64-69. Marchi sections to show the prevailing type of areas present in optic tract and optic nerve 

 (tigs. 64 and 65, x 10); in spinal cord (figs. 66 and 67, x 6), and in the brain (fig. 68, x 75, and fig. 69, x 10). 



Figs. 64 and 65. Showing "early " degeneration with rows of fat granule cells. 



Fig. 66. Small " early " area in the posterior columns {cf. fig. 313). 



Fig. 67. Posterior columns show a late stage of sclerosis with dense glia tissue staining darkly ; both 

 lateral columns show an " early " stage with rows of fat granule cells around the vessels. 



Fig. 68. Typical small " early " area in the central white matter. The tissue around a central blood- 

 vessel is permeated with fat granule cells. 



Fig. 69. Demyelinated " early " area at the tip of a medullary ray, extending through the radiations 

 almost to the superficial cortex — its medullary portion and the vessels radiating from it are permeated with 

 fat granule cells. 



Plates LI and LII (Case II) (pp. 690-694). 



Figs. 70-92. Various levels of brain and spinal cord. Kulschitsky-Pal with picro-fuchsin. 



Figs. 70-73. Horizontal sections through the cerebral hemispheres at the level of the middle (figs. 

 70-71) and upper part (figs. 72-73) of the basal ganglia. Note a = the very marked peri-ventricular 

 involvement, especially of the posterior horns and of the ventricular surfaces of the basal ganglia ; 

 6 = the numerous areas within the basal ganglia — one of which, on the left side, occupies the genu of the 

 internal capsule and involves both optic thalamus and lenticular nucleus; c = the demyelination of long 

 stretches of the medullary rays, involving frequently several convolutions, especially of the parietal lobe 

 and of the island of Keil, and extending into the grey matter; d = the continuation of the posterior horn 

 sclerosis towards the calcarine fissure — involving the optic radiations, the tapetum, and the inferior longi- 

 tudinal bundle. 



Figs. 74 and 75, x 2. Above the level of the roof of the right lateral ventricle. Sections show very 

 numerous isolated areas, most of which involve the medullary rays and the adjoining cortex. a = fig. 277 ; 

 i = fig. 288; c = fig. 280; d = fig. 278. 



Figs. 76-82. Sections of pons and mid-brain. Note the extensive peri-ventricular and peri-aqueductal 

 sclerosis — the cranial nuclei, without exception, being involved. Note also the extensive involvement of 

 the red nuclei (fig. 82). 



Fig. 76. Lower third of pons. x 2£. 



Fig. 77. Middle third of pons. x 2. Note a = the irregular areas of sclerosis passing as projections 

 from the floor of the IVth ventricle; 6 = zone of " shadow " sclerosis around area in the cerebellar white 

 matter. 



Fig. 78. Slightly higher than previous figure. x 2|. a = involvement of the hilum of each dentate 

 nucleus. 



Figs. 79 and 80. Upper third of pons. x 2^. 



Fig. 81. Level of decussation of the superior cerebellar peduncles, x 2£. 



Fig. 82. Mid-brain. x 2. Peri-aqueductal sclerosis with involvement of most of the structure of the 

 tegmentum, to the IHrd nuclei, and adjoining parts of both red nuclei (a). Several additional small isolated 

 areas in each red nucleus (&). 



Figs. 83-88. Various levels of the spinal cord. Myelin sheath stain. x 2. The sections are typical 

 of the almost complete demyelination of the whole spinal cord ; the still preserved fibres occupied, as a rule, 

 the marginal portions and showed a marked symmetry. 



Fig. 89, x 10. Cervical cord showing complete demyelination, condensation of the vessel walls, and 

 nerve roots staining almost normally. 



Fig. 90, x 2. Frontal longitudinal section of the dorsal cord showing a similar demyelination. 



Fig. 91, x 2. Nerve root and posterior root ganglion attached to the above segment. 



Fig. 92, x 2. Conus medullaris and nerve roots of cauda equina in longitudinal section, showing 

 normally staining nerve roots although the whole cord is demyelinated. 



