438 VEDDER AND CLARK. 



According to this observer, degeneration in a sectioned nerve 

 progi'esses uniformly throughout the peripheral part. Thus the 

 only condition in which we should expect to find more degen- 

 erated fibers in the peripheral nerves than in the sciatic would 

 be in the case of those fibers which branch as the periphery 

 is approached, both rami showing degeneration. 



Nerve roots. — The nerve roots in several cases were examined 

 after staining by the Marchi as well as by the Weigert and mito- 

 chondria methods. Degeneration was observed in both ventral 

 and dorsal roots by all these methods. However, degeneration 

 was more frequent and much more pronounced in the ventral than 

 dorsal roots. 



Ventral roots. — Degeneration in the ventral nerve roots of 

 the sciatic was pronounced in those cases in which degeneration 

 in the sciatic was marked and degeneration in the two (i e., 

 sciatic and nerve roots) was parallel and comparable; in fact, 

 teased preparations from the ventral nerve roots resembled very 

 closely teased preparations from the sciatic. In the ventral nerve 

 roots degeneration was easily demonstrated by all the methods 

 mentioned above. 



Dorsal nerve roots. — In those cases in which degeneration was 

 far advanced in the fibers of the sciatic, degeneration was dem- 

 onstrated in the dorsal nerve roots. In other cases it was more 

 difficult to demonstrate or was absent altogether. In only the 

 most advanced cases was degeneration to be seen after the 

 Marchi method. In other cases it required the mitochondria 

 method to bring out the changes. Owing to the difficulty in 

 teasing, the section method was frequently employed. The 

 changes in the dorsal nerve roots resembled more nearly the 

 earlier stages of degeneration in the fibers of the sciatic. Few 

 cases were seen where advanced degeneration was present. 



The spinal cord. — Degeneration within the spinal cord was 

 observed in the fiber tracts of all columns, and changes were 

 observed in the nerve cells of both ventral and dorsal horns. 



The fiber tracts. — ^When a specimen of the spinal cord from a 

 normal fowl is treated by the Marchi method, it shows in both 

 sectioned and teased preparations numerous small black areas. 

 In teased preparations (which are very difficult to obtain) and 

 in cross sections of the cord, these small black areas, which are 

 about the size of the smaller globules in a degenerated nerve, 

 are seen in close relation with the fibers in the cord. It is some- 

 times difficult to tell whether a given globule is vdthin the fiber 

 or in apposition to it. Naturally then other methods must also 

 be employed to confirm any suspected degeneration within the 



