— 132 — 
nerve-tubes, or nervous, processes give off side-branchlets on their 
way through the dotted substance, vide fig, 69, which represents- 
such a nerve-tube, seen in a section stained by the chromo-silver 
method; in the section a few lateral branchlets only were stained,, 
but I think it probable that there were more. The nerve-tubes 
spring from ganglion cells which are situated either on the same 
side as the peripheral nerve to which the nerve-tubes belong, or on 
the opposite side of the ganglion. 
Other nerve-tubes do not spring directly from ganglion cells, but 
arise from the dotted substance ly a union of stender primitivv 
tubes and fibrillæ, which unite to form thicker and thicker tubes. 
I have never succeeded in tracing a nerve-tube with such an origin 
to its finest branches; this is owing to the very complicated course 
of those nerve-tubes; they often originate on the same side as the- 
peripheral nerve to which they belong, but most frequently they 
originate on the opposite side. They then pass united to bundles,, 
or transverse commissures, from one side of the ganglion to the 
other. Though I have not been able to trace such nerve-tubes 
through the whole extent of their course, I have, however, seen 
their origin in portions and believe I am entitled to say that it is> 
as just described. 
When we now gather what will be the constituents of the 
dotted substance according to the above given investigations we will' 
have the following. 
1) The branches of those nervous processes which lose their 
individuality and are entirely broken up into fine branches. 
2) The side-branchlets of those nervous processes which di- 
rectly become nerve-tubes and do not lose their individuality (but 
which on their course through the dotted substance give off side- 
branchlets). 
3) The branches of those nerve-tubes which come from the 
longitudinal commissures, and which in the dotted substance are 
entirely broken up into slender branches. 
4) The side-branchlets given off from those nerve-tubes of the- 
longitudinal commissures which pass entirely through the ventral 
ganglia, only giving off branchlets to the dotted substance. 
5) The side-branchlets joining those nerve-tubes of the longi- 
tudinal commissures which spring directly from ganglion cells. These 
branchlets are partly the same as those mentioned in 2. 
6) The primitive tubes and branchlets, or fibrillæ, which unite 
