420 S. W. RANSON AND P. R. BILLINGSLEY 
that a gray ramus plunges directly into a ganglion, its fibers being 
lost in the fiber complex; while in the case of the white rami it is 
easy to see that a large part of the fibers do not enter the ganglion, 
but pass along its surface to join the trunk above or below. 
While the gray rami are composed in by far the greater part 
of unmyelinated fibers, each contains at least a few myelinated 
fibers and some contain a very considerable number. Langley 
(96 a) has shown that the number of such fibers has been greatly 
underestimated. The seventh lumbar gray ramus of the eat - 
may contain more than 3800. According to Edgeworth (’92), the 
branches from the stellate ganglion to the cervical nerves in the 
dog contain a few small myelinated fibers, but no large ones. In 
commenting on Edgeworth’s paper Langley (’92) states that he 
has always found some large myelinated fibers in the gray rami 
of the lower cervical and fourth, fifth, sixth, and seventh lumbar 
nerves. The number of small myelinated fibers is in general 
proportional to the size of the gray ramus, 1.e., to the number of 
unmyelinated fibers it contains (Langley, 96a). He states that 
the myelinated fibers range in size from 1.8 to 10u and the varia- 
tion in number affects almost entirely the small ones, the most 
constant form being the fiber of medium caliber. The number 
of myelinated fibers varies considerably in different mammals, 
there being many more in the cat than in the rabbit (Langley, ’00). 
Miiller (09) demonstrated the presence of myelinated fibers in 
the gray rami of man. 
In the rami to the first three cervical nerves from the superior 
cervical ganglion we found that the number of myelinated fibers 
varied greatly in different specimens. Most of these fibers were 
less than 3.5u in diameter, although occasionally larger fibers up 
to 6 or 7u were found, also in one case a single fiber measuring 
10u. We have examined sections of the ramus vertebralis of the 
stellate ganglion in one cat and found that it contained about 
the same proportion of myelinated fibers as the other gray rami. 
There were no fibers as large as 6u. All of the thoracic gray rami 
contain a few myelinated fibers. These are for the most part 
small, but a few large fibers were found in the upper thoracic 
gray rami. We cite some enumerations which may be regarded 
