342 S. W. RANSON AND P. R. BILLINGSLEY 
with those of the intercellular plexus, penetrate into the dendritic 
glomeruli and the dendritic crowns forming subcapsular plexuses 
in close relation to the subcapsular dendrites. This is well 
illustrated in figure 5, a. Cajal has considered these fine darkly 
staining axons as preganglionic fibers of spinal origin. From what 
has been said and from the accompanying illustrations it will 
readily be seen that these fibers are the same as those which form 
the intercellular plexuses in the superior cervical ganglion of the 
dog and cat. In a paragraph which follows evidence will be 
presented to show that these are fibers of spinal origin. 
Here and there in this plexus in the superior cervical ganglion 
of the dog or cat one can see faintly stained yellow axons about 
the size of the larger dark fibers forming the plexus. In many 
places these lightly staimed axons are united into bundles of 
parallel fibers which run as straight a course as is possible through 
the ganglion. These light yellow axons and the bundles into 
which they unite do not seem to belong to the plexus, although 
necessarily they run through it. The color contrast between 
the two kinds of fibers is quite sharp in good preparations, but 
since all gradations are found the color alone is not sufficient to 
distinguish them. The light axons are among the largest in the 
ganglion, are of uniform contour and apparently unbranched. 
They show a marked tendency to group themselves into bundles 
of parallel fibers in contrast with the more irregular course of the 
dark fibers: 
Distribution of nerve fibers in the ganglion. In regard to the 
termination of axons in the sympathetic ganglia, Cajal (11) 
states that in his first work in this field he described two kinds of 
terminal arborizations, one set representing the branches of the 
longitudinal sympathetic fibers arising in neighboring ganglia, 
the other representing branches given off by fibers from the white 
rami. That distinction does not seem probable to him any 
longer because of the results of Langley’s experiments and be- 
cause of the presence of many medullated fibers in the commis- 
sural cords which are known to come from the spinal cord (Lang- 
ley, ’03, and Miller, 09). Cajal now believes that the two 
kinds of terminations belong to spinal motor fibers, distinguished 
