90 ELBERT CLARK 



portion of the dorsal horn experienced marked changes, in their 

 chromophile, Nissl, or tigroid substance, the globules or flocculi 

 had given way to a uniform, finely granular mass collected at 

 one side of the nerve cell, usually at the base of one of the proc- 

 esses of the cell. I was not able to determine whether that 

 portion of the axone between the motor nerve cell and the pe- 

 riphery of the cord ever underwent segmentation. 



A close examination of sections of the cords of Nos. 38, 57, 

 61 and 64 has revealed a persistence of globules of degenerated 

 myelin in the medullated fibers of all columns of the cord for 

 59, 108, 275 and 379 days. These globules were frequently very 

 large and occupied the entire diameter of the fiber. Further- 

 more, a careful search has failed to reveal any evidence of regen- 

 eration in the fibers of the cord. No such proof of regeneration 

 as was found in the fibers of the sciatic and illustrated in figures 

 17 to 30 was found in the cord. Nothing suggestive of a new 

 axis cylinder, an outgrowth or branching of the same was seen 

 and there were not observed two axis cylinders in the same 

 fiber. 



On the other hand, fibers in degeneration in all columns of 

 the cord were found in which no new axis cylinder nor fragments of 

 the old were observed. Figure 31 is a cross-section of a degen- 

 erated fiber 49 days after complete recovery of fowl No. 38 

 (108 days in regeneration) was attained. A large globule of 

 degenerated myelin completely fills up and distends the sheath 

 and no indication of the axis cyfinder is to be seen. 



On comparing cross-sections of the lumbo-sacral cord of fowls 

 taken at the time paralysis developed with sections from the 

 same region of other fowls several months after complete recov- 

 ery, the data included in table 1 were obtained. 



From this table it will be seen that there are as many degen- 

 erated fibers with no axis cylinder in the cords of those fowls 

 killed several months after recovery, as in the cords of fowls 

 killed at the time paralysis developed. 



In the absence of any positive evidence of regeneration, the 

 persistence of degenerated fibers with no axis cylinder, in as great 

 numbers as at the height of degeneration, strongly suggests the 



