THE SYMPATHETIC NERVOUS SYSTEM 



343 



against the outer surface of the capsule of another cell (Fig. 252, B, C) ; (3) inter- 

 lacing branches, which form a plexus upon the outer surface of the capsule of 

 an adjacent cell (Fig. 252, D}. 



Dogiel (1896) thought that the cells possessing the longest dendrites were sensory, but 

 Cajal (1911) could find no evidence for this, and was unable to trace any of them from the 

 ganglia and associated nerves to the viscera. Carpenter and Conel (1914), using the size 

 and arrangement of the Nissl granules as a criterion,- were able to find only one cell type in 

 the sympathetic ganglia, and concluded that these ganglia do not contain sensory nerve-cells. 



Fig. 253. Neurons and intercellular plexus from the superior cervical sympathetic ganglion of a 



dog (pyridin-silver method). 



The axons of sympathetic ganglion cells are usually unmyelinated, but a few 

 of them acquire thin myelin sheaths. They are the postganglionic fibers which 

 relay the visceral efferent impulses to the innervated tissue. According to 

 Cajal (1911), who states that his anatomic studies are in accord with the physio- 

 logic experiments of Langley, the axons of the cells in the ganglia of the sympa- 

 thetic trunk dispose themselves in one of the three following ways: (1) Usually 

 they run transversely to the long axis of the ganglion to enter a gray ramus. 



