STUDY OF POLYNEURITIS GALLINARUM. 439 



cord. All the methods enumerated above (the Weigert and mito- 

 chondria methods) for the myelin sheath and . others for the 

 neuraxis were made use of to this end. 



Plate I, fig. 2, is a photomicrograph from the anterior lateral 

 portion of the white matter of the cord of a normal fowl after 

 Marchi method. The black areas shown at a are the globules 

 referred to, which stain black in the Marchi fluid. A careful 

 inspection will show that these are not within the fibers, but 

 are in close proximity to them. What these structures represent 

 we have not determined. At b two fibers show enclosures which 

 resemble very much the small droplets of myelin in a degenerated 

 nerve fiber. These we have noted occasionally here and there, 

 but have not interpreted them. However, despite these resem- 

 blances to degeneration of fibers in the normal cord, the picture 

 presented by a section or a teased preparation from the cord 

 of a fowl with well-marked paralysis is easily distinguishable 

 as one showing degeneration. 



In studying degeneration in the fibers of the spinal cord, 

 sections and teased preparations were made from the thoracic 

 cord. Since, as has been pointed out, the nerve roots of the 

 sciatic group show degeneration, a preparation from the lumbo- 

 sacral cord showing degeneration might indicate nothing more 

 than degeneration in the fibers of the roots passing up or down 

 the cord for a short distance. True degeneration in the columns 

 of the cord would be equally apparent in the thoracic region 

 where primary fibers of the sciatic group are absent, 



Plate VI, figs. 11 and 12, and Plate VII, fig. 13, are from the 

 thoracic cord of fowls with marked degeneration in the sciatic 

 nerve. Fig. 13 is low-power magnification of the lateral column 

 of the cord (as near the pyramidal tract as we could determine) 

 of a fowl whose sciatic showed marked degeneration. At a, 

 a', a", and a' " appearances strongly suggestive of degeneration 

 within the fibers are seen. Owing to the fact that the fibers 

 of the cord do not run a straight nor parallel course, it is 

 extremely difficult, and much a matter of chance, to get a long- 

 itudinal section which shows the course of a fiber except for 

 a short distance. Plate VI, fig. 11, a low-power magnification 

 of the dorsomesial (Goll's) columns of the cord of another fowl 

 with marked degeneration in the sciatic, shows at a, a', a", etc., 

 undoubted enclosures of degenerated myelin within the fibers. 

 Plate VI, fig. 12, is a higher magnification of a small area of 

 the same. Whatever the other dark areas may mean, there can 

 be little doubt that at a and a' two fibers are seen which contain 



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