HISTOLOGY. 83 



gal neuraxis of the Purkinje cell and the two types of 

 centripetal cells, one type sending their neuraxis into 

 the granular layer. These fibers are called mossy fibers 

 and do not extend through the granular layer. The 

 other type of cells sends the collaterals of the cells into 

 the layer where the Purkinje cells are found and seem 

 to ascend the neuraxis of the Purkinje cells, and are 

 called climbing fibers of the centripetal cells. The 

 central gray nucleus are found in the medullary por- 

 tion of the cerebellum, and are a number of multipolar 

 cells with many dendrites. The medullary or white 

 substance of the cerebellum is arranged in a layer of 

 branching sheets, and when cut, presents in the cut 

 section a tree-like arrangement, called arbor vitae. For 

 more extensive work on this subject see Leroy, So- 

 botta, and Bohm and Davidoff. 



THE MEDULLA OBLONGATA. 



This structure is the same as that of the spinal cord, 

 the chief difference being in the arrangement of the 



structures. 



SYSTEM OF SYMPATHETIC NERVES. 



This system is composed of a large number of gan- 

 glia and nerve fibers, connected by small fibers. The 

 fibers are non-medullated. They are arranged into 



