STUDY OF POLYNEURITIS GALLINARUM. 443 



numerous researches of Meves, Benda,(l4) Bensley, Regaud,(i5) 

 Renaut, and others have shown. For the great advance which 

 has been made in our knowledge of this subject, we are probably 

 justified in saying that mitochondria are identical with the 

 "Filarmasse" of Flemming, the "Bioblasts" of Altmann,(l6) 

 (Meves, Bensley, and others) , and are necessary for the metabolic 

 and functional activity of the cell. Regaud and others have 

 shown that mitochondria occur in normal nerve cells and Cow- 

 dry (17) and others have shown that they are distinct from the 

 tigroid substance and that the two occur simultaneously in the 

 same normal nerve cell. One of us (Clark) has not been able to 

 demonstrate them in certain pathologic cells (pancreas). An 

 examination of the nerve cells of the spinal cord of the fowls 

 with marked degeneration in the sciatic nerve by the mito- 

 chondria method shows rods and granules in cells of the type 

 which show such marked changes by the Nissl method. In the 

 cells of the thoracic cord it was practically impossible to dis- 

 tinguish between the cells from the normal and from the neuritic 

 fowl as regards mitochondria. The rods and granules were 

 perhaps a little less numerous in the latter cells, but this is far 

 from being definite. A cell with no mitochondria was not 

 observed in the lumbosacral cord of the more advanced cases. 



We are thus of the opinion that, along with degeneration in 

 the peripheral nerves and in the fiber tracts of the cord, there 

 occur changes in certain nerve cells of the anterior and posterior 

 horns of the spinal cord, which may or may not signify degenera- 

 tive changes, but which probably never progress to any great 

 extent before death of the fowl. 



Regeneration. — In the numerous experiments to bring about 

 recovery after prostration or after pronounced symptoms of 

 peripheral neuritis had manifested themselves, we have found 

 that fowls show as much individual variation here as they do 

 in developing the affection. Of fowls in which the symptoms 

 were distinctly those of peripheral neuritis (severe in nearly 

 all), recovery was acconiplished in almost every case. 



The nerves from fowls, carried toward recovery by feeding 

 for sixty days and which were apparently well, were examined 

 for degeneration. In a majority of the fibers only very small 

 blackened areas (Marchi's method) were to be seen. From 10 

 to 15 per cent of the fibers, however, showed segmentation and 

 globular arrangement of the myelin and no axis cylinder. The 

 globules were never large at this period, and the core of the fiber 

 within the neurilemma sheath contained relatively large amounts 



