gi Journal of Comparative Neurology. 



pass through it, and an excess in the trunk would be the natural 

 result. This explanation of the excess is illustrated in scheme I. 



C 



According to this scheme the medullated sympathetic fiber 

 enters the ramus {c) and passes to the ganglion where it ter- 

 minates in an end-brush about the body (^) of a Dogiel spinal 

 ganglion cell of type II. Thus it is seen that a section taken 

 immediately distal to the ganglion would contain two fibers, 

 whereas one taken central to the ganglion would include only 

 the central process of the ordinary spinal ganglion cell, or Do- 

 giel's cell of type I, (a). 



How numerous these medullated sympathetic fibers are, 

 which are present only on the distal side of the ganglion would 

 be difficult to determine. None of the observations so far made 

 have been attempts to determine their number. But none of 

 the descriptions of these fibers, nor Dogiel's ('96) description 

 of what he considers sensory cells in the sympathetic ganglia, 

 seem to justify the assumption that they are numerous enough 

 to account for the excesses which have been found. It seems 

 necessary therefore, to assume that, in addition to the fibers 

 arising in the sympathetic ganglia, there are also other fibers 

 present in the nerve trunk which do not occur in the roots. 

 The other possibility is the second one suggested by Gaule ; 

 namely, that fibers may arise in the spinal ganglion and pass to 

 the periphery without there being corresponding central pro- 

 cesses in the dorsal root. 



Three possible ways suggest themselves by which an ex- 

 cess in the trunk may occur according to this second suggestion 

 by Gaule. These possibilities can be illustrated by three 

 schemes. 



