HuBER, Sympathetic Nervous System. 129 



therefore that experiments with nicotin are not suitable for the 

 solution of the question under discussion. It may be said 

 that the evidence seems against the assumption that nicotin 

 paralyzes the endings of the neuraxes of sympathetic neurons, 

 as it does the endings (peri-cellular, intra-capsular baskets) of 

 the central fibers in the sympathetic ganglia. This hypothesis 

 is offered, as a suggestion, to explain certain sympathetic 

 effects which nicotin does not interrupt. 



The grey rami comniunicantes. — In a general way it may be 

 stated that each spinal nerve has a grey ramus. Langley (82) 

 states that in the cat the superior cervical ganglion gives off 

 dorsally, from its posterior surface, fibers to the first three 

 spinal nerves ; the stellate ganglion sends branches from the 

 Ilird cervical to the Ilird or IVth dorsal nerve inclusive. 

 From the Vth dorsal to the first coccygeal, there is usually a 

 sympathetic ganglion and grey ramus corresponding to each 

 spinal nerve. 



As has already been shown, structurally a grey ramus 

 consists largely of non-medullated nerve fibers, which, as Gas- 

 kel (78) states, are intimately connected with the correspond- 

 ing lateral ganglion, its nerve fibers being in direct connection 

 with the nerve cells of that ganglion. 



Langley (82), Langley and Sherrington (90) have made 

 some very interesting observations on the distribution of the 

 grey rami in two communications dealing with the pilo-motor 

 nerves of the cat and monkey. In their joint publication, they 

 point out that, in the monkey, stimulation of the cervical, and 

 in the cat, stimulation of the lumbar sympathetic causes a con- 

 traction of the erectores pilorum in certain definite areas of 

 the skin, thus causing an erection of- the hairs in these areas. 

 The nerve fibers going to these muscles are spoken of as pilo- 

 motor nerves. 



Langley (82) has found that the pilo-motor fibers run from 

 the spinal cord in the anterior roots of the spinal nerves. And 

 further finds that, "Nicotin annuls the pilo-motor effect of 

 stimulating the roots of the spinal nerves (as it does all the vis- 

 ceral effects), but does not effect the the pilo-motor effect of 



