HuBER, Sympathetic Nervous System. 135 



spinal cord." They further conclude that such reflexes are due 

 to motor nerves. 



The view which they tentatively express is the following. 

 They suppose that on stimulating a peripheral nerve, the im- 

 pulse may travel up this peripheral nerve until it reaches a col- 

 lateral branch (in this case in the inferior mesenteric ganglion), 

 then down the collateral branch, and that this impulse may set 

 up other impulses in the sympathetic nerve cells. The follow- 

 ing diagram (Fig. 12), which is slighly modified from one given 

 by Langley (88) in his short account of the sympathetic sys- 

 tem, Physiological Congress, Berne, 1895, may serve to illus- 

 trate the point in question. 



A and A', a central (pre -ganglionic) fiber ; B, a collateral 

 branch ; C and D sympathetic neurons with neuraxes [a) end- 

 ing in the bladder, Bl. The central fiber is stimulated at A', 

 the arrows indicate the course the impulse would travel in a 

 peripheral reflex. I am not prepared to make comment on this 

 hypothesis, as suggested by Langley. It would seem well, 

 however, to regard it as tentative until further work, both 

 physiological and histological, corroborates or disproves its 

 accuracy. Possibly the existence of sensory sympathetic cells, 

 the cell bodies of which are located in the inferior mesenteric 

 ganglion, the dendrites of which extend into one of the hy- 

 pogastric nerves, may be found, in which case a peripheral re- 

 flex in this ganglion might take place through such sensory 

 cells. 



In closing these lectures, I desire to draw your attention to 

 two diagrams, by means of which I hope to summarize in a 

 graphical way many of the points I have emphasized in these 

 lectures. 



These diagrams may serve to show, — (i) the probable ar- 

 rangement of the spinal nerves in a metameric segment, and 

 their connection with the sympathetic ganglia of the chain, the 

 pre-vertebral ganglia and peripheral ganglia ; (2) the probable 

 connection of the nerves concerned in the innervation of the 

 sub-lingual and submaxillary glands. 



Fig, 1 3, Showing the probable arrangement of the neu 



