456 S. W. RANSON AND P. R. BILLINGSLEY 
spending white ramus, but these may have belonged to a small 
eray ramus accompanying it. 
When the sympathetic trunk was cut caudad to the ninth 
thoracic ganglion all the fibers degenerated in the oval well 
myelinated field in the twelfth thoracic internodal segment, 
except in a fascicle derived from the tenth and eleventh white 
rami, which entered the trunk caudad to the cut. The fibers 
in this oval field, therefore, come from the spinal cord and spinal 
ganglia by way of the white rami; at least this experiment proves 
that none of them in the twelfth thoracic internodal segment 
come from the ganglia of the sympathetic trunk below the ninth, 
and under the circumstances there is no reason to suppose that 
they might come from those situated farther cephalad. In 
this experiment the greater splanchnic nerve was degenerated 
except for a small bundle of fibers that could be traced into it 
from the fascicle representing the white rami of the tenth and 
eleventh nerves, and a very small number of unmyelinated fibers 
obviously associated with a small group of ganglion cells located 
in the course of the nerve. It is clear that in this case the 
splanchnic nerve received no fibers from the ganglia of the sym- 
pathetic trunk below the ninth, and there is every reason to 
believe that all of its fibers, except those arising from the small 
ganglion located in its course, came from the spinal cord and 
spinal ganglia (p. 4384-4386). Exclusive of an occasional well- 
defined bundle of obviously postganglionic fibers found in two 
out of ten normal specimens of the greater splanchnic nerve, 
the unmyelinated fibers of this nerve are derived from spinal 
ganglia by way of the white rami. The number of rami from 
which this nerve may receive fibers seems to vary, but it usually 
does not contain any from those below the ninth. 
LITERATURE CITED 
Lanauey, J. N. 1900 The sympathetic and other related systems of nerves. 
Schiifer’s text-book of physiology, vol. 2. 
2aNSON, S. W., anp v. Hess, C. L. 1915 The conduction within the spinal 
cord of the afferent impulses producing pain and the vasomotor reflexes. 
Am. Jour. Physiol., vol. 38, p. 128. 
Van GeuucuTen, A., AND Motyant, M. 1910 Les lois de la dégénérescence 
wallérienne directe. Le Névraxe, vol. 11, p. 75. 
