DEGENERATION AND REGENERATION OF NERVE FIBERS 521 
with each other to form a network, the meshes of which are 
drawn out in a longitudinal direction. 
c. Early branching of axons in the immediate neighborhood of 
the lesion. The fibers which give rise to these branches undergo 
no degeneration at the point of division nor do they form at 
their cut extremity a darkly staining zone of reaction. We 
are dealing here with fibers which either possessed a greater 
vitality or were less severely traumatized in the cutting of the 
nerve. There seem to be two chief modes by which the branches 
arise from these fibers: 
1. Some of these fibers begin to grow distally very soon after 
the lesion and by the end of the first day have grown out of 
their sheaths into the exudate. Here they immediately break 
up into a great number of fine branches. Figure 16 represents 
two such fibers one day after the operation. At c and c’ they 
are leaving their sheaths and growing into the exudate. A 
large fusiform lateral branch is given off from one of the fibers. 
This large lateral branch, as well as the two main fibers, show 
the neurofibrils very clearly—these fibrils are however more 
nearly parallel in their arrangement and not so closely set as 
in the zone of reaction shown in figure 14, 6, and on the whole 
give the ends of the fibers a much more normal appearance. 
At many points these axons give off fine fibrillar branches which 
end in small cylindrical or spherical expansions. In the sur- 
rounding exudate there are numerous isolated rings which repre- 
sent cross sections of the expanded ends of other fibers. This 
is a very characteristic ending for the fine branches of the medul- 
lated axons at this stage—an elongated club-shaped end bulb 
whose fibrillar substance is located at the periphery, in cross 
section appearing as rings and in longitudinal section as hollow 
clubs. 
2. Instead of arising from the ends of axons, extremely fine 
side branches may arise from the surface of the axon within 
its sheath. Axons giving rise to branches of this sort show no 
degenerated stretch near the lesion nor any dark zone of reac- 
tion. They show however a certain amount of fibrillar disso- 
ciation in that the axons are swollen and the fibrils are much 
