CH. XVII.] NERVE-CELLS 197 



all ultimately terminate in an arborescence of fibrils in various end 

 organs (end-plates, muscle spindles, etc.). 



In the grey matter of the cerebrum the nerve-cells are various in 

 shape and size, but the most characteristic cells are pyramidal in 

 shape. They are especially large and numerous in what are called 

 the motor areas of the brain. The apex of the cell is directed to the 

 surface ; the apical process is long and tapering, and finally breaks 

 up into fibrils that lie parallel to the surface of the brain (tangential 

 fibres). From the lower angles and other parts branching processes 



Axon 



FIG. 211. Cell of Purkinje from the human cerebellum. Golgi's method. 

 (After Szymonowicz.) 



originate ; the axis cylinder comes off from the base of the pyramid. 

 (See figs. 209, 210). 



The grey matter of the cerebellum contains a large number of 

 small nerve-cells, and one layer of large cells. These are flask-shaped, 

 and are called the cells of Purkinje. The neck of the flask breaks up 

 into branches, and the axis cylinder process comes off from the base 

 of the flask (fig. 211). 



The whole nervous system consists of nerve-cells and their 

 branches, supported by neuroglia in the central nervous system, and 

 by connective tissue in the nerves. Some of the processes of a 

 nerve-cell break up almost immediately into smaller branches ending 

 in arborescences of fine twigs ; these branches, which used to be 



