SACRAL SYMPATHETIC TRUNK OF CAT 97 
years. In these specimens there constantly appeared a greater 
number of large medullated (dorsal root) fibers than was antici- 
pated would enter the trunks through the gray rami. This large 
number of specimens was used to assure the writer that these 
fibers could not possibly be due to failure of degeneration or to 
regeneration through union of the divided trunk ends. The 
results obtained in all of these specimens are characteristically 
uniform and it will therefore be sufficient to describe the changes 
from normal in one example. 
In the specimen to be described sections were cut serially 
beginning with the first sacral ganglion, the trunk having been 
divided just cephalad to the ganglion. The left trunk was 
stained with osmic acid, the right with silver nitrate. 
In the pyridine-silver preparations of the ganglia the nerve 
cells and their dendrites are stained as in normal specimens, 
although the dendrites can be followed for a greater distance 
owing to the absence of axonic terminations. The characteristic 
change is in the intercellular plexus. The fine axonic termina- 
tions seen in normal pyridine-silver preparations have entirely 
disappeared. The few fascicles of fibers which remain do not 
stain as darkly as the fibers of the intercellular network and the 
majority can be traced into the gray rami. A few appear to 
form small but definite fascicles in the internodal segments and 
apparently enter successive rami or branches of distribution. 
Figure 6 shows a section of sympathetic ganglion after degen- 
eration of the preganglionic fibers. The elimination of the inter- 
cellular plexus by section of the sympathetic trunk caudad to the 
lowest white ramus was anticipated in view of the results obtained 
by Ranson and Billingsley (’18 a) in the superior cervical ganglion. 
In osmic-acid preparations, however, the results appeared at 
first more difficult to explain. 
A section through the upper third of the first sacral ganglion 
showed sixteen small medullated fibers, all under 3.5u. Near 
the lower pole of the ganglion a ramus containing eleven medul- 
lated fibers of various sizes from 1.5 to 9u separated from the 
_ trunk. There was only one fiber of 9u in diameter, one 8u, one 
6u and all of the others were under 5uy. 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL, 33, NO. 1 
