460 VEDDER AND CLARK. 



Plate V. 



Fig. 9. Advanced degeneration in a nerve fiber from the sciatic, shoM^ing 

 also segmentation of the axis cylinder. Swelling of the medul- 

 lary sheath and the granular appearance of the axis cylinder 

 are v^^ell shown: a, axis cylinder; n, node of Ranvier. Hzema- 

 toxylin and acid fuchsin. Zeiss .3 X W-^ oil immersion. Reduced 

 one-half. 



10. Cross section of fibers of the ventromarginal column of the thoracic 

 cord from fowl 14, showing pronounced symptoms of peripheral 

 neuritis and marked degeneration in the sciatic nerve. At a and 

 a' two fibers are seen in which the axis cylinder has undergone 

 fragmentation and granulation. Hasmatoxylin and acid fuchsin. 

 Zeiss 4 X Yy^ oil immersion. 



23. Fiber from the ventral portion of the midbrain of fowl 72 with 

 pronounced neuritis. Small globules of degenerated myelin are 

 clearly seen. Marchi method. Leitz 3x6. 



Plate VI. 



Fig. 11. Transverse section of the posterior folumns of the thoracic cord 

 of fowl 14, showing pronounced symptoms of peripheral neuritis 

 and marked degeneration in the sciatic. At a, a' and a", three 

 fibers are seen which undoubtedly contain globules of de- 

 generated myelin. Marchi method. Zeiss 4 x AA. apr. 

 12. High-power illustration of same preparation as fig. 11 — dorso- 

 marginal (Gall's) column. Degenerated areas within the 

 fibers are clearly seen at a and a'. Marchi method. Zeiss 

 4X4 apcr. 



Plate VII. 



Fig. 13. Longitudinal section of lateral column of thoracic cord of fowl 

 15, showing pronounced symptoms of peripheral neuritis and 

 marked degeneration in the sciatic nerve. At a, a', a", and 

 a'", fibers are seen containing globules and droplets of de- 

 generated myelin. Marchi method. Zeiss 4 x AA. apcr. 

 14. Longitudinal section of the sciatic nerve of a normal fowl stained 

 by the mitochondria (iron-hsematoxylin) method. The stain- 

 able substance is seen in the form of little rods arranged 

 radially around the axis cylinder. Note fibers a, a', and a". 

 At a the rods show a tendency to cross. Zeiss 4X4 apcr. 



Plate VIII. 



Fig. 15. Longitudinal section of the sciatic nerve of a fowl fed for seven 

 days on polished rice to illustrate the changes in the medullary 

 sheath. The stainable substance is seen as larger or smaller 

 irregular and branched masses. In fiber b a network formation 

 is seen. Mitochondria (iron-hsematoxylin) method. Zeiss 4X4 

 apcr. 

 16. Same, from a fowl fed for eleven days on polished rice. The 

 segmentation is a little more pronounced and in some fibers 

 the masses are larger. Note fibers a, h, c, and d. Zeiss 4X4 

 mm. apcr. 



