NERVE CELL CONNECTLON OF FLBRES. 647 



degenerated fibres can be traced into the strand. In the cat, after 

 degenerative section of the first five lumbar nerve roots, it was found by 

 Anderson and myself 1 that the several inferior splanchnic nerves in 

 nearly every case had no effect when stimulated, although the colonic 

 fibres and the hypogastrics caused contraction of arteries and the 

 remainder of their customary actions. 



Occasionally, after injection of nicotin in the rabbit, a rise of 

 1 or 2 mm. of arterial pressure may follow on stimulation of the 

 splanchnics. Theoretically, I see no adequate reason why some nerve 

 cells which send their fibres to the abdominal viscera, should not be 

 situated in the vertebral ganglia, for it is a probable assumption that 

 the pre-vertebral and the vertebral ganglia have separated from a 

 common mass, and in that case it might easily happen that the separa- 

 tion would not be strictly carried out. In the ganglion stellatum the 



Spinal Sympathetic Solar 



Cord Chain Ganglion 



Pre -'Sn npi/Pfi ic fibre 



Post-gang/ionic fibres 



Spinal Sympathetic Solar- Peripheral 



Cord Chain Ganglion- Ganglion 



Preganglionic fibre 



A^ Pt>sf-ga.ngli'onic fibres 



.., y Pre-gans/ionic fibre 

 B. 



<'$>- 



Spinal Sympathetic Solar 



Cord Chain Ganglior 



Pre '■ga.ns/ioh'C fibr? 



Post -^anplgn/c /tirei 



r-<-E£t — 



\ It&spPosf-ga.ngPonic fibre \ 



c. " 



Fig. 313. 



separation does not appear to have taken place, or only partially. But if 

 the slight rise of blood pressure mentioned above be taken as showing 

 the occasional presence of a few fibres proceeding from cells in the 

 vertebral ganglia, it is clear that they run to the periphery without 

 having nerve cells in their course, unless we suppose that the connection 

 of sympathetic nerve cells with other nerve cells is not paralysed by 

 nicotin, a supposition on which I shall later have something to say (p. 685). 

 There is, however, good evidence that some efferent fibres run through 

 the inferior mesenteric ganglion, pass down the hypogastric nerves, and 

 end in connection with cells of the pelvic plexus. A sufficient proof of 

 this is the degeneration of nerve fibres which takes place in the hypo- 

 1 Journ. I'/u/siu/., Cambridge and London, 1894, vol. xvi. p. 432. 



