444 S. W. RANSON AND P. R. BILLINGSLEY 
The white ramus of the eleventh thoracic nerve contained 
myelinated fibers of all sizes in about equal proportions. These 
were scattered fairly evenly throughout the cross-section and 
were separated by a large amount of degenerative material (fig. 
3). It was obvious that the preganglionic fibers had degen- 
erated as the result of the section of the ventral root. The fibers 
which remained were afferent and arose from the cells in the 
spinal ganglia. These afferent myelinated fibers were of all 
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Fig. 3 Eleventh thoracic white ramus of the cat after the degeneration of all 
the preganglionic efferent fibers. All of the remaining fibers are afferent. Osmic 
acid. X 425. 
sizes, as is shown in the illustration, but as a rule there are rela- 
tively more large ones than in this ramus. 
In the serial sections the degenerated eleventh white ramus 
could be traced into the trunk above the level of the twelfth 
thoracic ganglion (fig. 4 a). Here it occupied a position super- 
ficial to that occupied by the degenerated fibers from the tenth 
(fig. 4b). The rest of the oval field was occupied by large and 
small myelinated fibers and was normal in appearance. Only 
a small part of this is shown in the illustration. 
