154 ELEMENTS OF HISTOLOGY. [Chap. xvm. 



long-branched and pursuing a vertical course towards 

 the surface ; sooner or later they all break up into the 

 fine nerve-ground network of the grey cortex. The 

 longest processes reach near to the surface. The 

 layer (b) above mentioned i.e., the cortical grey 

 matter is in reality the terminal nerve network for 

 the branched processes of the ganglion cells of 

 Purkinje. Sankey maintains that in the human cere- 

 bellum there are also other smaller multipolar gang- 

 lion cells connected with the processes of the cells of 

 Purkinje. 



202. The nuclear layer contains a large number of 

 spherical or slightly oval relatively small nuclei em- 

 bedded in a network of fine fibrils, the nature of 

 which is not definitely ascertained i.e., whether it 

 consists of neuroglia only, or whether it contains, 

 in addition, also a network of nerve fibrils. The latter 

 is exceedingly probable. The nuclei are nuclei of 

 neuroglia cells, of lymph corpuscles and of small gang- 

 lion cells. 



The axis cylinder process of the ganglion cell of 

 Purkinje passes through the nuclear layer, and be- 

 coming invested with a medullary sheath, enters as 

 a medullated nerve-fibre the central white matter. 

 There are, however, medullated nerve- fibres of the 

 central white matter, which are not connected with an 

 axis cylinder process of a Purkinje's cell, but enter 

 the nuclear layer and probably terminate there in the 

 nerve network, or pass through it and terminate in the 

 nerve network of the grey matter of the cortex. 



203. II. The pons Varolii (Fig. 91) is a pro- 

 longation partly of the medulla and partly of the 

 cerebellum. Of the latter only white matter passes 

 transversely into the anterior portion of the pons, 

 and forms there the transverse bundles of nerve-fibres, 

 which give to the pons the horizontal striation. 



As we pass upwards i.e., farther away from the 



