398 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



THE CEREBELLUM. 



The cerebellum is next in size to the cerebrum and 

 overlies the fourth ventricle. It is characterized by 

 transverse curved sulci which divide it into lamellae, 

 giving the organ a foliate appearance. A cross sec- 

 tion of the lamellae shows a central core of white 

 matter with a gray cortex, giving the section the 

 appearance of a branching tree, hence the name arbor 

 mtcz. A section taken in this plane presents the 

 following layers : 



1. Molecular layer on the outside. 



(1) Small cortical cells. 



(2) Stellate cells. 



(3) Cells of Purkinje. 



2. Granular layer. 



1 i ) Granular cells . 



(2) Large stellate cells. 



3. Medullary substance core of nerve fibers. 



(1) Centrifugal neuraxes from Purkinje cells. 



(2) Centripetal neuraxes. 



(a) Mossy fibers. 



(b) Climbing fibers. 



(3) A few ganglion cells forming the central 



gray nucleus. 



Molecular Layer. The small cortical cells are 

 found in all parts of this layer, but more especially 

 near its periphery. They are multipolar cells and 

 but little is known of the distribution of their neu- 

 raxes. The stellate cells are evenly distributed, and of 

 particular interest are their neuraxes. The latter pos- 

 sess two types of collaterals. One set forms branches 

 among the cortical cells, while a second class branches 



