450 VEDDER AND CLARK. 



9. Degeneration was observed in both dorsal and ventral nerve 

 roots, being most pronounced in the latter. 



10. Degenerative changes in both axis cylinder and medullary 

 sheath were seen in fibers of all columns of the thoracic spinal 

 cord. (Plate V, fig. 10, Plate VI, figs. 11 and 12, Plate VII, 

 fig. 13.) 



11. Changes were observed (Nissl method) in certain large 

 cells of both ventral and dorsal horns of the gray substance of the 

 lumbosacral cord. In the cells of both horns, the tigroid bodies 

 were not visible, and the stainable material was collected at one 

 side of the cell around the base of one of the processes. Cells 

 were occasionally seen whose nuclei stained very poorly. (Plate 

 X, fig. 22.) 



12. Mitochondria were observed in the nerve cells of the lumbo- 

 sacral cord, even though there was a pronounced alteration of 

 the tigroid bodies. The mitochondria here were of similar ap- 

 pearance and almost or quite as numerous as in corresponding 

 cells of the normal cord. 



13. In the medullary sheath of fibers of the sciatic nerve of 

 normal fowls numerous small, bacilli-like rods, arranged radially 

 around the axis cylinder, were made apparent by the various 

 mitochondria* methods. These structures are probably mito- 

 chondria. (Plate VII, fig. 14.) 



14. Fowls show alteration in the medullary sheath of the 

 sciatic fibers after only seven days on a polished rice diet. In the 

 sciatic fibers of fowls fed for seven days on polished rice alone, 

 the rods are scarcely to be observed. Instead, the stainable 

 "material shows remarkable alterations and occurs in the form of 

 irregular, branched, and anastomosing masses. (Plate VIII, 

 fig. 15.) 



15. In fowls fed for a longer period, these masses show, in 

 a certain percentage of the fibers, progressive changes which man- 

 ifest themselves in the form of more definite skeins and seg- 

 mentations and larger masses and globules of stainable material. 

 In fibers showing marked degeneration by the Marchi method 

 these, occur as larger or smaller vesicular, oval globules and 

 correspond to the black globules shown by the Marchi prepara- 

 tions. Plate VIII, fig. 16, and Plate IX, figs. 17 and 18 illustrate 

 these changes. 



16. When fowls are fed on polished rice and in addition given 

 some protective substance, such as is contained in extract of 

 rice polishings or in various foods, but in insufficient quantity 

 to confer complete protection, the disease appears in its char- 



