DEGENERATION AND REGENERATION OF NERVES 81 



lated fibers of the rice-fed fowls at the time of paralysis, multi- 

 plication of the nuclei of the neurilemma sheath and the embry- 

 onic nerve fibers were conspicuous by theii- absence from the 

 nerves of the latter fowls. Could regeneration be accomplished 

 in such nerves, without a multiplication of the neurilemma nuclei, 

 the significance of the embryonic nerve fiber would be minimized. 



With the above questions in mind, regeneration was studied 

 in the sciatic nerve of fowls which came down in 20 to 30 days 

 with marked leg paralysis and which were, from time to time, 

 "placed on a regeneration diet. To recapitulate briefly certain 

 observations noted above; in fowls of this class, those medullated 

 fibers, presenting at the time of paralysis the most marked degen- 

 eration showed, at most, only a doubtful increase in the number 

 of nuclei of the neurilemma sheath and no embryonic nerve 

 fibers. Nerves of fowls killed after feeding from 4 days to 2 

 months on the regeneration diet never showed the marked multi- 

 plication of the nuclei of the neurilemma sheath or the embryonic 

 nerve fiber, as has been constantly described for mammalian 

 nerves after section, and as was found also in the nerves of fowls 

 in which I had transsected the sciatic. Segments of the sciatic 

 of one side cut out and compared with the sciatic of the other 

 side at a later date, showed that in none of these cases had the 

 looked for change in this respect taken place. In other nerves 

 after 108, 125, 171 and 275 days in regeneration, the nuclei of 

 the sheath of Schwann could not be said to be more numerous 

 than in preparations taken at the time paralysis developed, and 

 the embryonic nerve fiber could not be found. The close resem- 

 blance of the Marchi preparation from fowls 108 days and 171 

 days on a regeneration diet to those from fowls at the time of 

 paralysis has also been pointed out and is clearly seen by com- 

 paring figures 2, 3, 4 and 5 with figures 13 and 14. Numerous 

 large globules and small droplets of degenerated myelin are to 

 be seen in each. 



In view of this condition of the myelin, the uniform absence 

 of embryonic nerve fibers, and the fact that a great majority of 

 fibers of the sciatic do not show a breaking up of the axis cylin- 

 der at the time of paralysis, it was at first suspected that regen- 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 24, NO. 1 



