— 131 — 
It is, however, not only the nervous processes which subdivide 
or give off branches to the dotted substance and thus contributes 
to its formation ; the nerve-tubes coming from the longitudinal com- 
missures and from the peripheral nerves also do the same. 
That the largish nerve-tubes of the longitudinal commissures sub- 
divide to some extent in the gangha, may already be concluded 
from the fact that, in a transverse section through the central 
part of a ventral ganglion, only a very small number of trans- 
sected large nerve-tubes is seen. The many largish nerve-tubes of 
the commissures must, therefore, either have passed to the peripheral 
nerves, or they must have subdivided, or have become diminished 
by giving off lateral branchlets, or finally they may originate in 
ganglion cells. On examination of longitudinal sections stained 
with hæmatoxylin etc. it may be seen that these longitudinally 
running nerve-tubes subdivide, in the ganglia, to a great extent. 
The contents of the longitudinal commissures radiate into the dotted 
substance of the ganglia, and are to some extent lost in it owing to 
the subdivisions of the nerve-tubes. 
On examination of longitudinal sections of preparations success- 
fully stained by the chromo-silver method this is of course seen 
much more distinctly. In such sections, I have seen longitudinal 
nerve-tubes which were broken up by subdivisions into fine primitive 
tubes and fibrillæ (vide fig. 64, j, 3, u). 
I have, however, also seen longitudinal nerve-tubes passing 
undivided through the ventral ganglia and into the commissures 
quitting them at the other side. Sometimes I have observed such 
nerve-tubes to give off side-branchlets to the dotted substance of 
the ganglia through which they pass (cf fig. 64, 2, g, 3, 9, lo)- 
I believe that some of the longitudinal nerve-tubes pass to ganghon 
cells, and are connected witht their nervous processes, or, in other 
words, that they are direct continuations of the nervous processes. 
I have certainly in no preparation succeeded in really observing such 
a direct connection; I have, however, seen so many indications of 
its probable existence that I do not think there can be much doubt 
about it. These nerve-tubes do not, however, have any isolated 
course, they give off side-branchlets to the dotted substance. 
The nerve-tubes of the peripheral nerves originate in the 
ganglia in two, or rather three, ways. 
Some nerve-tubes spring directly from ganglion cells, being di- 
rect continuations of nervous processes, as before mentioned. These 
