SACRAL SYMPATHETIC TRUNK OF CAT 93 
the same general features. In pyridine-silver preparations the 
dendrites radiating out from the nerve cells as well as the post- 
ganglionic axones appear rather lightly stained and can be traced 
for only a short distance away from the cell body, usually not 
more than a distance equal to the diameter of a nerve cell multi- 
plied by approximately one to four. The greater part of the 
plexus is formed by fibers of lesser diameter and of much darker 
staining properties. The fine axonic ramifications of this plexus 
give the same appearance as those shown by Ranson and Billings- 
ley (18 a) to disappear from the superior cervical ganglion upon 
degenerative section of the cervical trunk. A section of normal 
ganglion stained by silver nitrate is shown in figure 5. 
Osmic-acid preparations of normal ganglia show chiefly the 
variously sized medullated fibers. The majority of these fibers 
occupy distinct bundles which lie at the periphery of the ganglion. 
Small medullated fibers (1.5 to 4u) are scattered throughout the 
ganglion and occasionally a fair-sized bundle containing larger 
fibers was seen in the interior of the ganglion. At intervals in 
serially mounted sections small bundles of variously sized medul- 
lated fibers were seen to separate from the main group and form 
part of the gray rami (fig. 3). 
The internodal segments. A considerable number of non- 
medullated fibers was seen in pyridine-silver sections of the 
sacral and coccygeal internodes. Small groups of these fibers 
are scattered irregularly among the medullated fibers throughout 
the section. Neither the size of the individual groups of fibers 
nor their distribution appeared to bear any constant or suggestive 
arrangement in different specimens. The crescent-shaped fasci- 
cle observed by Ranson and Billingsley (18 b, p. 426) in the 
thoracic trunk does not appear to be present in the sacral and 
coccygeal portions. 
The medullated fibers, afferent and preganglionic efferent, 
are best seen in sections stained by osmic acid. In the internodes 
at some distance from the ganglia these fibers are distributed 
evenly over the field of a cross-section (fig. 2). As they pass 
through the ganglia the medullated fibers occupy a periphera! 
position. A gray ramus may be given off from the lower pole 
