410 S. W. RANSON AND P. R. BILLINGSLEY 
gray and white rami run close together and join the trunk at the 
level of the corresponding ganglion. From the level of the ninth 
or tenth thoracic nerve to the fourth lumbar the white rami are 
directed caudad and reach the truncus below the level of the 
ganglion to which the corresponding gray rami run, often at the 
level of the next ganglion below. In some cases a nerve may give 
off, in addition to this descending white ramus, a direct one which 
accompanies the gray ramus to the segmental ganglion. 
A nerve may be connected with the corresponding ganglion by 
more than one gray ramus or a nerve may receive gray rami from 
two successive ganglia. This is particularly likely to be the 
case in the lower thoracic and lumbar regions where, in addition 
to the gray ramus from its own segmental ganglion, a nerve may 
receive a bundle of unmyelinated fibers from the next more caudal 
ganglion, which bundle accompanies the descending white ramus 
of the nerve. Langley (’94) has shown that ‘“‘when the white 
ramus runs downward to a ganglion, as occurs from the ninth or 
tenth thoracic to the fourth or fifth lumbar nerves, the ganglion 
may supply pilomotor fibers to the two nerve areas, thus the 
fourth lumbar ganglion sends fibers to the fourth lumbar nerve 
by its gray ramus, and may also send fibers to the third lumbar 
nerve by the white ramus of this nerve.” 
Gaskell (86) has shown that when a gray ramus is followed 
toward its corresponding spinal nerve it can usually be seen to 
give off branches which ramify in the connective tissue overlying 
the vertebrae. On these branches accessory ganglia may some- 
times be found. In some cases the gray ramus could be seen to 
divide on reaching the spinal nerve, part of the fibers passing 
centrally, the rest peripherally. 
The splanchnic nerves. In the cat the splanchnic fibers leave 
the sympathetic trunk in a series of six to ten small nerves. 
The first of this series is the largest and corresponds to the greater 
splanchnic nerve in man. The level of the trunk at which this 
nerve is given off varies. In a total of seventeen dissections it 
took origin from the thirteenth thoracic ganglion in six cases, 
from the thirteenth internodal segment in three, from the first 
lumbar ganglion in four, from the first lumbar internodal 
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