382 P. R. BILLINGSLEY AND S. W. RANSON 
these rami contained, if anything, fewer myelinated fibers than 
the other branches of the superior eervical ganglion. 
It will also be clear that there could be no considerable number 
of preganglionic or afferent fibers regularly running toward the 
superior cervical ganglion in any of its branches without their 
presence being indicated in such tabulated data as has already 
been presented. The small number of myelinated fibers present 
in most of these branches as well as the great variation in the 
ratio of such fibers to the area of the nerve speaks against these 
fibers being anything other than postganglionic fibers which 
have acquired myelin sheaths, and this apparently without rule 
or regularity. 
The internal carotid nerve is the one which most regularly 
contains a high absolute and relative content of myelinated 
fibers. But, as has already been said, degeneration experiments 
show that this nerve contains no preganglionic fibers continued 
into it through the ganglion from the sympathetic trunk. Onthe 
other hand, Langley (’96) has shown that section of this nerve 
close to the ganglion causes degeneration of its myelinated fibers, 
which shows that these fibers are running from and not toward 
the ganglion. His statements appear to apply to all the branches 
of the superior cervical ganglion, but we are not sure that he 
means to include more than the large anterior branches going to 
the carotid artery. He says: 
On section of the branches peripherally of the ganglion, nearly all the 
fibers which remain connected with the ganglion are unaffected, whilst 
nearly all the fibers separated from the ganglion degenerate. Hence, 
then, nearly all the medullated fibers contained in the nerve strands 
given off by the superior cervical ganglion arise from nerve cells in that 
ganglion. As to the remaining fibers I have shown (J. Physiol., 14, 
p. II) that in the dog there are usually two small bundles which pass 
from the tympanic plexus to the internal carotid artery, and run thence 
to the superior cervical ganglion by the side of the anterior branches of 
the ganglion. Probably in the cat there are some homologous nerve 
fibers. 
In a few specimens of certain of the branches a limited number 
of larger myelinated fibers were found. See tables 1, 3, and 4. 
In one specimen of the internal carotid nerve not recorded in 
