520 THE ORGANS 



branches which end in varicosities. These terminal branches are 

 located within the glomeruli. The glomeruli thus contain the 

 dendritic terminations of the granule cells, the axonal terminations 

 of the Golgi cells, and the terminations of the mossy fibres. (Figs, 

 351 and 350.) 



The climbing fibres pass from the white matter, through the 

 granular layer to the cells of Purkinje. Passing by the bodies of the 

 latter they arborize into terminals which envelop the smooth dendritic 

 branches of the Purkinje cells; i.e., all but the terminal dendritic 

 arborizations. (Fig. 351, n). Three kinds of fibres thus terminate 

 around the Purkinje cells; the granule axones, probably in contact 

 with its terminal dendritic arborizations; the climbing fibres around 

 its coarser dendritic branches; and the basket fibres around its 

 body. The respective sources of the mossy and climbing fibres are 

 unknown. There is some evidence that the climbing fibres are 

 from the pons. 



It is evident from the above that all of the cells of the cerebellar 

 cortex except the Purkinje cells are association cells of the cortex. 



The medullated fibres of the cerebellum (Fig. 352) pass from 

 the white matter into the granular layer and ramify throughout 

 the latter, forming quite a dense plexus separating groups of granule 

 cells. Sometimes straight fibres can be seen passing through toward 

 the molecular layer which are probably either the climbing fibres or 

 axones of the Purkinje cells. Beneath and between the bodies of the 

 Purkinje cells is a plexus of fibres extending into the deeper part of 

 the molecular layer, the remainder of this layer containing few or no 

 medullated fibres. These fibres in the vicinity of the Purkinje cells 

 are probably principally formed by the recurrent collaterals of the 

 Purkinje cells already mentioned. The remaining fibres of the 

 granular plexus would apparently consist of the arborizations of 

 mossy fibres and of the Golgi cells. Whether the former are medul- 

 lated is, however, somewhat uncertain. 



Most of the neuroglia cells in the cerebellum are of the same 

 general type as seen elsewhere, but in the Purkinje cell layer are 

 apparently epithelial-like cells which send vertical processes to the 

 periphery. Some of these processes, as seen in the Golgi method, 

 are rough and branched, others are smooth. In ordinary stains 

 these processes are sometimes visible and are known as the fibres 

 of Bergmann. , (Figs. 346, 351.) 



