428 THE CENTRAL NERVOUS SYSTEM. 



shaped unipolar, bipolar, and multipolar cells, the cell-bodies of 

 which are surrounded by nucleated capsules, continuous with the 

 neurilemma of their neuraxes. In the sympathetic ganglia of mam- 

 malia and birds the great majority of sympathetic neurones are 

 multipolar, although in nearly all ganglia a small number of bipolar 

 and unipolar cells are to be found, usually near the poles of the 

 ganglia. 



The dendrites of the sympathetic neurones in any one ganglion 

 branch repeatedly. Of these branches, some extend to the per- 

 iphery of the ganglion, where they interlace to form a peripheral 

 subcapsular plexus, while others interlace to form plexuses between 

 the cell-bodies of the neurones in the interior of the ganglion 



O O 



pericellular plexuses. These pericellular plexuses are external to 

 the capsules surrounding the cell-bodies of the sympathetic neurones. 



Fig. 342. From section of semilunar ganglion of cat ; stained in methylene-blue, intra 

 vitam (Huber, Journal of Morphology, 1899). 



The neuraxes of the sympathetic neurones, the majority of 

 which are nonmedullated, the remainder surrounded by delicate 

 medullary sheaths, arise from the cell-bodies either from implanta- 

 tion cones or from dendrites at variable distances from the cell- 

 bodies, leave the ganglion by way of one of its nerve-roots, and 

 terminate in heart muscle tissue, nonstriated muscle, and glandular 

 tissue, and to some extent in other ganglia, both sympathetic and 

 spinal. Terminating in all sympathetic ganglia are found certain 

 small medullated nerve-fibers, varying in size from about 1.5 // to 

 3 fjt. The researches of Gaskell, Langley, and Sherrington have 

 shown that these small medullated nerve-fibers leave the spinal 

 cord through the anterior roots of the spinal nerves from the first 

 dorsal to the third or fourth lumbar and reach the sympathetic 



