GANGLIA. 



429 



ganglia through the white rand comnmnicantes. Similar small 

 medullated nerve-fibers are found in certain cranial nerves. These 

 small medullated nerve-fibers, which may be spoken of as white 

 rami fibers, after a longer or shorter course, in which they may 

 pass through one or several ganglia without making special con- 

 nection with the neurones contained therein, terminate in some 

 sympathetic ganglion in a very characteristic manner. After enter- 

 ing the sympathetic ganglion in which they terminate, they branch 

 repeatedly while yet medullated. The resulting branches then lose 

 their medullary sheaths and divide into numerous small, varicose 

 nerve -fibers, which interlace to form intracapsular plexuses, which 

 surround the cell-bodies of the sympathetic neurones. In the 

 sympathetic ganglia of mammalia such intracapsular pericellular 



Fig. 343. From section of stellate ganglion of dog, stained in methylene-blue and alum 

 carmin : a, white ramus fiber ( Huber, Journal of Morphology, 1899). 



plexuses may be very simple, consisting of only a few varicose 

 nerve-fibers, or very complicated, consisting of many such fibers. 

 In the sympathetic ganglia of reptilia, in which are found very 

 large sympathetic neurones, the white rami fibers are wound spirally 

 about the cell-bodies of such neurones before terminating in com- 

 plicated pericellular plexuses. In the frog and other amphibia the 

 sympathetic neurones are unipolar nerve-cells. The white rami 

 fibers terminating in the sympathetic ganglia of amphibia are wound 

 spirally about the single processes of these unipolar cells while yet 

 medullated fibers, but they lose their medullary sheaths before ter- 

 minating in the intracapsular pericellular plexuses. From what 

 has been said concerning the white rami fibers and their relation to 

 the sympathetic neurones, it is evident that the sympathetic neu- 



