BRANCHES OF GANGLION CERVICALE SUPERIUS 381 
first three cervical nerves. On page 419 we will consider the 
structure of the gray rami ard the character of the myelinated 
fibers they contain. A majority of them are postganglionic. 
Sometimes, but not commonly, a few preganglionic fibers, pass- 
ing to the sympathetic trunk by white rami, leave it again by gray 
rami to end among small groups of cells lying in these rami. 
There are also a few afferent medullated fibers in the gray rami. 
Most of these enter the trunk through white rami and run out 
again through the gray. But it may be that a few, especially 
the larger ones, run to the sympathetic trunk by the gray rami. 
These statements are based on Langley’s (’96) experiments in 
which by a variety of experimental lesions he caused the degenera- 
tion of different groups of fibers and in this way determined the 
origin of the myelinated fibers in these rami. 
There is no reason for supposing that the myelinated fibers in 
the other branches of the superior cervical ganglion differ from 
those in the grayrami. The majority are certainly postganglionic 
fibers. After section of the sympathetic trunk in the neck and 
complete degeneration of all the preganglionic fibers ascending 
to the superior cervical ganglion there is no degeneration of the 
myelinated fibers in the internal carotid nerve. Hence no pre- 
ganglionic fibers go through the ganglion into this nerve (p. 321). 
The great variation in the proportion of myelinated fibers in 
different specimens of the same branch of the ganglion can only 
be understood on the assumption that the postganglionic fibers 
occasionally acquire myelin sheaths, but that there is no regular- 
ity in this. No special functional group of-these fibers acquires 
such a sheath regularly or exclusively. The way in which the 
myelin sheaths are distributed seems to be entirely accidental. 
Kolliker (94) was of the opinion that some functional groups 
of postganglionic fibers were better myelinated than others; for 
example, the pilomotor fibers of the cat were supposed to be 
covered throughout by myelin sheaths, while the fibers to the 
intestine, liver, and spleen soon lost their sheaths. If the pilo- 
motor fibers were myelinated, consistently, and in any consider- 
able number, we should find a different picture in the gray rami 
through which these fibers are distributed. But, as we have seen, 
