DEGENERATION AND REGENERATION OF NERVE 
- FIBERS 
S. WALTER RANSON 
From the Anatomical Laboratory of the Northwestern University Medical School! 
TWENTY-NINE FIGURES 
The series of experiments upon which this paper is based 
was begun with no idea of taking up the question of the regen- 
eration of nerve fibers, but with the much more restricted pur- 
pose of studying the degeneration of the non-medullated fibers 
of the spinal nerves. After it had been demonstrated that the 
spinal nerves contain many more non-medullated than medul- 
lated fibers (Ranson 711) it was very desirable that the Wal- 
lerian experiment should be repeated to determine the direction 
of degeneration in these fibers. Work had not progressed far, 
however, before it became evident that observations were being 
made that had a bearing on the perplexing question of nerve 
regeneration and made it necessary to enlarge the scope of the 
investigation while not abandoning its original object. 
Since, as has been intimated, we shall be concerned in part 
with the degenerative and regenerative phenomena in the non- 
medullated fibers, it will be best to indicate at this point the 
facts which have been previously ascertained in regard to these 
fibers. 
When ordinary staining methods are used it is possible to 
see in the spinal nerves only those fibers which possess a myelin 
sheath, since axons not so covered cannot be differentiated 
from the connective tissue of the endoneurium. But when 
1 Some of the work, on which this paper is based, was done in the Anatom. 
biol. Institut, Berlin, the Anatom. Anstalt, Freiburg i. Br. and the Physiol. 
Institut, Freiburg i. Br. To the directors of these institutes I am indebt or 
many courtesies. 
487 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 22, NO. 6 
DECEMBER, 1912 
