44 Journal of Comparative Neurology and Psychology. 



sympathetic character in the ramus. They belong to the smaller 

 type of fibers. The larger of them have a medullary sheath 

 which is relatively thinner than that of fibers of undoubted spinal 

 origin and which stains less black with osmic acid and shows a 

 tendency to collapse in the sections. The smallest of the medul- 

 lated fibers in the rami, however, cannot be distingushed from 

 the smallest of the fibers known to arise in the spinal cord and 

 spinal ganglia. Otherwise differential counts could be made to 

 determine their exact proportion in the trunk. As is well 

 known, the rami contain fibers from both the ventral roots and 

 spinal ganglia. The larger of these may be distinguished by the 

 character of their sheaths. 



Fibers considered of sympathetic character were always 

 observed in the dorsal branches. When the dorsal branches 

 are much divided, often a small twig may be seen with the ma- 

 jority of the fibers in it of this type. This suggested that fibers 

 from the sympathetic ganglia may enter the nerve trunk by way 

 of the ramus, traverse it to the peripheral border of the spinal 

 ganglion and there pass into the dorsal branches without con- 

 necting with the spinal ganglion. Such fibers would of course 

 be counted twice, once in the trunk and once in the dorsal 

 branches and thus contribute to the distal excess. A special 

 search was made for such fibers and none were found which 

 could be so construed with certainty. If any exist they must be 

 very few and it was assumed that the distal excess cannot be 

 very materially affected by them. I think it necessary to explain 

 at least most of the sympathetic fibers in the dorsal branches in 

 some other way, and suggest that certain of the so-called mul- 

 tipolar cells in the spinal ganglia have to do with them. There 

 are numerous observations (cited above) noting the presence of 

 these cells and many ascribed to them a sympathetic char- 

 acter — cells left over in the spinal ganglia during the period of 

 the offshoot of the anlage of the sympathetic. Telodendria of 

 the centripetal sympathetic fibers are described as terminating 

 about these cells and the role presumed for them here is that 

 they are merely interposed in a sympathetic chain of neurones 

 and that the fibers given off by them pass by way of the dorsal 



