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 nervous network of the grey cortex. The 

 longest processes reach near to the surface. The 

 layer (6) 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 

 cerebellum there are also small inultipolar 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 nuclei embedded 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 ex- 

 ceedingly probable. The nuclei are nuclei of neuro- 

 glia cells, of lymph corpuscles and of small ganglion 

 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 pens 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 



