498 OTTORINO ROSSI 
pyridin-silver method of Ranson. So far as their researches 
concern the question of which we speak, we find the experiments 
described on pages 450 and 451 of their work highly interesting, 
because the authors give exhaustive and exact description of 
our medullated fibers and also establish the fact that we meet 
also afferent fibers without myelin sheath. On the ground of 
their experiments, Ranson and Billingsley conclude that the 
section of thoracic spinal nerve roots proximal to the spinal 
ganglia results in a degeneration of all of the preganglionic auto- 
nomic fibers in the corresponding white rami, but leaves the 
afferent fibers intact, and that, on the contrary, the latter fibers 
degenerate after section of the nerve distal to the corresponding 
spinal ganglion. Only in one case, after section of the tenth 
thoracic nerve distal to the spinal ganglion, the authors found 
a half-dozen normal myelinated fibers in the corresponding white 
ramus, but they suppose that these may belong to a small gray 
ramus accompanying it. 
Certainly, in view of what we know about wallerian degenera- 
tion, we should be obliged to conclude from these researches that 
the Ké6lliker’s fibers take origin from cells of the spinal ganglia: 
but we would not be able to state whether these cells are of 
common or of special type. Furthermore, one could advance 
an hypothesis which might be considered too hazardous and 
perhaps strange, but which could not be entirely disproved. 
The studies of Langley and Graupner (12) have taught that we 
meet nerve fibers belonging certainly to the sympathetic system 
which are covered by an evident myelin sheath; therefore, one 
eould think that those nerve fibers of the white rami which 
remain intact after cutting the dorsal root proximal to the gan- 
glion and also the anterior root might be sympathetic postgan- 
glionic fibers entering the corresponding spinal ganglion with 
blood-vessels and coming off through the rami communicantes. 
In sum, we express the opinion that Kolliker’s view is strongly 
supported by the researches stated under A and B, but we could 
not deny that doubts, already expressed by Onuf and Collins 
(13), are still vexing the minds of investigators. Therefore, we 
must consider of paramount importance further researches which 
