5 8o 



THE NERVOUS SYSTEM 



of three kinds: i. Descending fibers, that are made up of the axis-cylinders 

 of the cells of Purkinje, carrying impulses down from the cerebellar cortex. 

 2. Ascending fibers, which pass into the granular layer, and there end in a 

 number of very short, finely divided brushes of fibers presenting a mossy 

 appearance, so that these are known as the mossy fibers. These connect 

 with the granular cells of this layer. 3. Ascending fibers, which pass up 



FIG. 386. Transverse Section Through a Cerebellar Folium (after Kolliker). Treated 

 by the Golgi method. P, Axone of cell of Purkinje; F, moss fibers; K and K', fibers from 

 white core of folium ending in molecular layer in connection with the dendrites of the cells 

 of Purkinje; M, simple cell of the molecular layer; GR, granule cell; CR 1 , axones of granule 

 cells in molecular layer cut transversely; M', basket cells; ZK, basket work around the cells 

 of Purkinje; GL, neuroglia cell; N, axone of an association cell. 



through the granular into the molecular layer and there break up into a fine 

 network which interlaces with the dendritic branches of the cells of Purkinje. 



Paths through the Cerebellar Cortex. It will be seen that the ar- 

 rangements for the transmission and diffusion of nerve impulses and for the co- 

 operation of different cells are extremely complicated and delicate. It is not 

 possible to indicate absolutely by any schema the course of fibers and the 

 course of impulses through the cerebellum, but approximately it is some- 

 what like that in the accompanying figure 387. 



Impulses pass up along the ascending fibers to the granular cells' by way of 

 the direct cerebellar, the fibers of the gracile and of the cuneatus, from the 



