88 SYDNEY E. JOHNSON 
therefore produce easily interpreted results, as the field is cleared 
of the terminations of all preganglionic efferent fibers, leaving 
only the postganglionic fibers and the terminations, connections, 
or fibers which are intraganglionic, interganglionic, or reach the 
trunk by way of the gray rami. ‘The fine axonic ramifications 
of the intercellular plexus, if formed entirely of preganglionic 
efferent terminations, should completely disappear, but if formed 
in part by intraganglionic or other intrinsic commissural con- 
nections, these should remain undisturbed. One would also 
expect marked changes in the internodal segments. As they are 
largely composed, in the sacral region, of anterior and posterior 
root fibers, which descend from a higher level, there would be 
expected to follow practically complete dropping ‘out of the 
medullated fibers as well as the non-medullated fibers of central 
origin. ‘The consideration of these facts led to the experiments 
described in this paper. 
MATERIAL AND METHODS 
Cats were used for the experiments. In a series of twelve 
the sympathetic trunks were divided between the seventh lumbar 
and the first sacral ganglion. For a second series of experiments 
two cats were employed and each received a double operation. 
The first operation was the same as that described above. The 
second operation, performed a week later, consisted of an exten- 
sive laminectomy and, in one of the two specimens, removal of 
the entire cauda equina and conus medularis, and in the other, 
division of the spinal nerve roots (on the right side) cephalad 
to and including the seventh lumbar. The dorsal roots were 
divided distal to the spinal ganglia. All specimens were kept 
for a degeneration period of from twenty-five to thirty days.. 
At the end of this time the success of the operation was verified 
and the portions of the trunks under investigation were removed 
and stained with osmiec acid or by the pyridine-silver method. 
Transverse serial sections were cut at 10x. 
In addition to the experimental material, several normal 
series of slides of the same parts of the sympathetic trunk were 
made to serve as controls and for comparison. 
