DEGENERATION AND REGENERATION OF NERVE FIBERS 489 
And the present paper will be concerned only with the results 
of section of the sciatic nerve. 
The majority of those who have worked with the problem 
of the regeneration of nerves had previously taken a definite 
position in the contest over the neurone theory and sought in 
their experiments on nerve regeneration to find evidence which 
would aid them in maintaining that position. The supporters 
of the neurone theory believed that the axons were formed 
embryologically as outgrowths from ganglion cells and were 
regenerated from the axons of the central stump toward the 
periphery. On the other hand, the opponents of the neurone 
theory believed in a multiple origin of the axons from the cells 
along the course of the embryonic nerves, and described a simi- 
lar discontinous origin of the new axons in regenerated nerves 
by a differentiation of the protoplasm formed from the old 
neurilemma cells. The present writer, having never committed 
himself in the matter of the neurone theory, was able to take 
an entirely unprejudiced attitude and was led to his present 
position as he studied the regenerative phenomena which 
appeared, unexpectedly and with great clearness, in the prep- 
arations of the divided sciatic nerve. 
SURVEY OF THE LITERATURE ON THE REGENERATION OF NERVES 
Even before the time of Waller the subject had received some 
attention, but it was he who first recognized the true nature 
of the degenerative and regenerative processes in nerves. He 
stated (52) that that portion of a divided nerve fiber separated 
from its trophic center underwent complete degeneration and 
that regeneration took place through an outgrowth of new 
fibers from the central undegenerated stump. His conclusions 
were not at once accepted, however, and even to the present day 
the outgrowth of the new axons from those of the central stump 
is a matter of debate. It would tax too heavily the reader’s 
patience to review the literature from Waller’s time to the present 
date, but this is made unnecessary by the excellent reviews of the 
early literature, given in the articles of Howell and Huber (’92) 
and Stroebe (95). According to the summary given by Howell 
