ANALYSIS OF THE SYMPATHETIC TRUNK 449 
staining of these fibers was not very satisfactory, however. 
On one side of the trunk there was a rather large area containing 
scattered normal myelinated fibers, many of which were of large 
size. This area represented the contribution of the tenth and 
eleventh white rami, and the myelinated fibers in this area were 
the afferent fibers from these rami. Among these normal myelin- 
ated afferent fibers were considerable numbers of unmyelinated 
fibers, also of normal appearance and showing a marked tendency 
to arrange themselves in groups, as seen in figure 5.. Through- 
out the rest of the trunk all the fibers, both myelinated and unmy- 
elinated, were degenerated. The fibers in this completely degen- 
erated area had their cells of origin located above the point 
of section of the trunk, and from what has already been said in 
this and the preceding paper we know that they entered the trunk 
by way of the white rami above the tenth. The tenth and 
eleventh white rami contributed the fibers found in the area which 
is only partly degenerated, and since the roots of the corresponding 
spinal nerves were cut proximal to the spinal ganglia the only 
normal fibers which these rami could contribute would be afferent 
with cell bodies located in the spinal ganglia. We are therefore 
justified in interpreting as afferent all the fibers in this area, in- 
cluding large and small myelinated and unmyelinated fibers. 
We have both osmic acid and pyridine silver preparations of 
the greater splanchnic nerve. This was almost completely 
degenerated. There was, however, at one side a small group of 
normal myelinated fibers. These could be seen in both osmic 
acid and pyridine silver preparations. In the latter, as shown in 
figure 6, there were also some normal unmyelinated fibers to be 
seen iia gldd with the others. The rest of the splanchnic was 
completely degenerated except for a very small bundle of unmye- 
linated fibers on the other side of the cross-section. In con- 
nection with this bundle there were some nerve cells and the 
fibers of this group were probably to be regarded as postganglionic, 
arising from the cells of a small ganglion in the course of thé 
splanchnic. The bundle of myelinated and unmyelinated fibers 
was clearly a continuation of a part of that found in the trunk 
and illustrated in figure 5. 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 29, No. 4 
