Ranson, spinal Nerves. 



115 



else the peripheral count so Httle in excess that they regarded it 

 merely as a matter of technical error and attached no significance 

 to it. Later, Birge ('82) found an excess of fibers on the periph- 

 eral side of the II C. ganglion of the frog amounting to 16 per 

 cent; and Buhler ('98), also working on the frog, found in one 

 nerve an excess of 25 per cent. Hardesty ('99, '00, '05) has 

 spoken of these extra fibers as the "distal excess" and found that 

 it varied in the frog from 5 per cent to 61 per cent. Gaule and 

 Lewin ('96) found a distal excess in three of the sacral nerves 

 of a rabbit of 19 per cent, 11 per cent, and 15 per cent, respec- 

 tively. My observations on the II C. nerve of the white rat are 

 confirmatory of these previous results. Here we have to do with 

 a distal excess of 8 or 10 per cent. This is of interest since Dale 

 ('00) found in coccygeal nerves of cats an average distal excess of 

 only 0.63 per cent. 



table VI. 



Showing the Distal Excess in the II C. Nerve of the Adult White Rat (Ranson). 



Hardesty has made a careful study of the possible explana- 

 tions oi this distal excess. It is much too complicated a question 

 for us to enter upon here. It can only be said in passing that there 

 is evidence for the presence of medullated fibers of sympathetic 

 origin which pass through the nerve to end in the ganglion and, 

 hence, would not be found in either of the roots. There is also 

 evidence that both sensory and motor fibers may bifurcate at the 

 level of the ganglion. But after a careful consideration of all the 

 possibilities, Hardesty does not think any one cause sufficient to 

 explain the facts and believes that several factors must operate 

 together in the production of the distal excess. The idea of 

 NissL, discussed in a previous section, that the dorsal root fibers 

 pass through the ganglion without making any connections and 

 are there joined by others arising in the ganglion, would, if it 

 should be found correct, offer an adequate explanation of the dis- 

 tal excess, especially of those cases where the excess is large and 



