344 S. W. RANSON AND P. R. BILLINGSLEY 
ery of the ganglion and these can be followed into its various 
branches of distribution. These fibers are stained yellow or 
light brown in contrast to the darker fibers entering by way 
of the trunk. The staining reaction of these axons is exactly 
like that of the bundles of ‘sympathetic fibers’ described in the 
vagus and its branches by Chase and Ranson (’14) “where they 
are differentiated from the vagus fibers by their lighter stain.”’ 
We have repeatedly noticed this characteristic light staining 
of postganglionic autonomic fibers in the various spinal and 
cerebral nerves. Here the contrast with the darker unmyelin- 
ated fibers of cerebrospinal origin could not easily be overlooked. 
It is true that these lightly stained axons run among the cells 
and therefore through the intercellular plexus, but the great 
bulk of that plexus is composed of fibers whose staining reaction 
resembles that of the fibers entering by way of the sympathetic 
trunk. And the impression is gained by a study of such serial 
sections that this intercellular plexus is formed by the fibers de- 
rived from the trunk, and that the other fibers run through the 
plexus as directly as possible to their point of exit from the 
ganglion. Were it not for the difference in the color of the two 
kinds of axons, however, the impression would undoubtedly be - 
given that the plexus is formed by fibers that stream into the 
ganglion through all its branches. This is the impression that 
Dogiel, Huber, and Michailow have gained from the study of 
methylene blue preparations. 
The proof that the intercellular plexus is formed by the rami- 
fications of the preganglionic fibers is furnished by the experi- 
ment of cutting the sympathetic trunk in the neck and allowing 
time for degeneration to take place. Pyridine silver preparations 
of the superior cervical ganglion in which the preganglionic fibers 
have degenerated show no trace of an intercellular plexus (fig. 
12). Our technique does not stain the finer branches of the 
dendrites and these do not appear in either the normal or altered 
ganglia, but the fine axonic ramifications that form the normal 
network are gone. One can readily recognize small bundles of 
the lightly staining postganglionic fibers and many such fibers 
running an isolated course. But these fibers do not coil and 
