STUDY OF POLYNEURITIS GALLINARUM. 437 



In cross sections of nerves of other fowls we found, respect- 

 ively, fibers in advanced degeneration as follows : 



a. Four in a total of 208 fibers in a peripheral nerve and 5 in 285 of the 

 sciatic. 



b. Five in a total of 193 fibers in a peripheral nerve and 7 in 421 of the 

 sciatic. 



c. Four in a total of 154 fibers in a peripheral nerve and 10 in 368 of 

 the sciatic. 



These figures represent advanced degeneration in one plane, and as noted 

 above do not include all the fibers showing advanced degeneration. 



We are then unable to distinguish any anatomical difference in 

 degeneration in the central portion of the sciatic and its periph- 

 eral branches as to extent, degree, or time of onset. Thus 

 we are of the opinion that degeneration progresses uniformly 

 throughout the course of the fibers ,as has been shown to be 

 the case in the peripheral portion of a sectioned nerve. Nor 

 should we expect, either from the symptoms of neuritis shown 

 by the fowl before death or from our knowledge of experimental 

 degeneration of nerves, that in the present case degeneration 

 would begin at the periphery and progress centrally. Within 

 a few hours after showing the first symptoms of neuritis the 

 fowl usually "comes down" and is unable to walk. The proximal 

 portion of the sciatic in these fowls shows advanced degeneration. 



We know from curare experiments, fatigue experiments, cold 

 block, etc., that when a motor nerve ending is placed out of 

 commission, the nerve itself is of no more service than if it were 

 completely degenerated or sectioned. Stimulation by any means 

 whatsoever produces absolutely no effect on the muscle which 

 it supplies. Now, in polyneuritis in fowls on a polished rice 

 diet, should degeneration progress from the periphery, the fowl 

 would show paralysis just as soon as degeneration in the periph- 

 eral rami or in their end organs had progressed to a certain 

 extent. This in all cases would be before degeneration to a 

 similar degree or extent occurred in the sciatic (from which the 

 peripheral nerves arise), and we should expect to find fowls 

 that had just developed paralysis, in which the peripheral nerves 

 showed advanced degeneration and whose sciatic showed only 

 the earlier stages or none whatever. As stated above, we have 

 not observed this condition in a single fowl. On the contrary, 

 there are proportionately just as many nerves showing a break- 

 ing up of the axis cylinder in the sciatic as in its more periph- 

 eral rami. This, indeed, is the exact parallel of the condition 

 in peripheral nerves showing degeneration after section as was 

 shown by Monakow.(lO) 



