726 DR JAMES W. DAWSON ON 



Figs. 325-342. Evolution of a sclerotic area — •through a stage of fat granule cell formation : spinal 

 cord — longitudinal direction of nerve fibres. 



,, 349-360. Ditto. Spinal cord — transverse direction of the nerve fibres. 



,, 361-369. Ditto. Cerebral white matter — transverse direction of the nerve fibres. 



,, 370-378. Ditto. Cerebral white matter— longitudinal direction of the nerve fibres. 



,, 343-348. Ditto. Through a stage of increasing glia hyperplasia. 



,, 379-384. Types of glia cell changes and glia fibril development. 



,, 385—390. Changes in cerebral cortical areas. 



,, 397-402. Positive and negative pictures — meyelin sheath and neuroglia stains. 



,, 403-408. Changes in the transition zones of areas. 



„ 409-420. ,, related to ganglion cells. 



,, 421-432. ,, ,, axis cylinders. 



,, 433-450. ,, ,, blood-vessels. 



„ 451-456. ,, ,, nerve roots, etc. 



Plate XLV. 



Figs. 1-4. Successive stages in the evolution of a sclerotic area in the posterior columns of the 

 cervical spinal cord. Sections are cut in the longitudinal direction of the nerve fibres (p. 563) and 

 show a gradually increasing glia fibril formation. Cf. figs. 325-336. Figs. 1 and 3, Ford-Robertson's 

 methyl-violet stain; figs. 2 and 4, palladium methyl- violet. x 400. a = glia nuclei; 6 = glia fibrils; 

 c = fat granule cells ; d = persistent axis cylinders. 



Fig. 5. An "early" area in the cerebral white matter (cf. fig. 361): shows a central blood-vessel (b), 

 a peripheral nucleated zone (d), and is composed almost wholly of fat granule cells (c) and proliferated glia 

 cells, seen only as nuclei (a) under this power. Heidenhain's iron-hsematoxylin. x 26. 



Fig. 6. Area in the cerebral white matter. Numerous fat granule cells in the upper part of the draw- 

 ing with an already advanced degree of fibril formation : few fat granule cells in the lower part with a still 

 more advanced fibril formation — the glia nuclei almost wholly isolated from the fibril, a = protoplasmic 

 glia cells with processes differentiated into fibrils; 6 = glia fibrils; c = fat granule cells; d = g\i& nuclei 

 isolated from the fibrils. Heidenhain's iron-hsematoxylin. x 350. (P. 567.) Cf. figs. 361-369. 



Fig. 7. Types of proliferated glia cells with varying degrees of fibril formation, a = fibrils recurring 

 near nucleus; 6 = glia nucleus forming nodal point from which fibrils radiate. Cf. figs. 382-384. Heiden- 

 hain's iron-hsematoxylin. x 400. 



Plate XLVI. 



Figs. 8-12. Successive stages in the evolution of a sclerotic area in the posterior columns of the 

 cervical spinal cord. Sections cut transversely to the direction of the nerve fibres (p. 565). Cf. figs. 

 349-360. Van Gieson's stain. x 350. a = glia nuclei ; b = blood-vessel ; c = fat granule cell; d — myelin- 

 ated nerve fibre ; e= finely granular glia tissue; /= naked axis cylinder; g = transition to normal tissue. 



Fig. 8. Shows a commencing enlargement of the nucleus, cell body, and processes of the glia cells and 

 a commencing change in the myelin. 



Fig. 9. Stage of glia cell proliferation and fat granule cell formation. Note the multi-nucleated glia 

 cells, the presence of numerous deeply-stained nuclei in the tissue, the swollen and faintly-staining axis 

 cylinders, and the " Gitter" structure of the fat granule cells. 



Fig. 10. Tissue is composed almost wholly of fat granule cells, many of which have accumulated within 

 the adventitial sheath of the blood-vessels. 



Fig. 11. Stage of advancing sclerosis : the glia fibrils, cut transversely, are represented as closely com- 

 pressed fine dots ; the persisting axis cylinders stain deeply ; a few fat granule cells are still left in the tissue. 



Fig. 12. Stage of advanced sclerosis. The tissue is dense and finally granular, contains numerous axis 

 cylinders and a few fat granule cells — chiefiy within the adventitial sheath of the capillaries. On the left 

 transition to the normal tissue of the cord. 



I i vs. 13-15. Sequence of changes in the blood-vessels (p. 614). Cf. figs. 433-450. Van Gieson's 



