510 S. WALTER RANSON 
there remains a connective tissue strand consisting of connective 
tissue fibers and very long spindle cells.’”’ These cells, accord- 
ing to him, arise from the spindle shaped connective tissue 
cells which appear between the nerve fibers shortly after division 
of the nerve. He adds: 
But before we assume that these are true connective tissue cells, 
we must seriously consider one objection. We know that between 
the medullated nerve fibers there were bundles of non-medullated 
fibers. Could not these spindle cells represent cells associated with 
the non-medullated fibers and be homologous to the cells of Schwann’s 
sheath? This objection has, however, many weak points. 
It is clear that Perroncito is here describing the same phe- 
nomena which we have interpreted as the formation of proto- 
plasmic bands from the non-medullated fibers. His drawings 
show, however, that his preparations clearly differentiated little 
more than the nuclei in question. The pyridine-silver prepa- 
rations, on the other hand, clearly differentiate, not only the 
degenerating non-medullated fibers, but also the protoplasmic 
bands derived from them. 
While a few non-medullated fibers, probably of sympathetic 
origin, may persist for two or three weeks, all non-medullated 
fibers in the peripheral stump undergo degeneration before the 
end of the fourth week. This shows that the direction of Wal- 
lerian degeneration is the same for the non-medullated as for 
the medullated fibers, and excludes the possibility that any of 
them might arise from cells located at the periphery, unless 
one cares to. consider the very remote possibility that the slowly 
degenerating non-medullated axons undergo a cellulipetal degen- 
eration toward peripherally located sympathetic ganglion cells. 
3. Abortive autogenous regeneration in the distal stump 
It will be remembered that all the descriptions and drawings 
in the two preceding divisions of this paper refer to the distal 
stump at a distance of at least 5 mm. from the cut surface. It 
was necessary to choose a point at some distance from the cut 
surface, because changes occur in the immediate neighborhood 
of the lesion which are essentially different from those seen in 
