318 



MANUAL OF HISTOLOGY. 



of a collection of small fusiform and polyhedral cells with 

 minute processes, imbedded in a basis- substance much more 

 dense than the surrounding white matter. The body is made 

 to appear striated in a peripheral direction by bundles of 

 fibres and blood-vessels pursuing a parallel course. 



The surface of the cerebellum, deeply gashed by sulci and 

 their subdivisions, presents, on section, its well-known com- 

 pound, arborescent appearance. This arrangement of the gray 

 matter causes the greatest possible surface to come in con- 

 tact with the blood-current furnished by the pia mater, and 

 hence secures the greatest nutrition of the elements of the 

 cortex. The gray matter of the cortex is easily divisible into 

 an external or granular layer, a middle or cellular layer, and 

 an internal or nuclear layer. The latter consists of a vast 

 number of small granular cells about the size of white blood- 

 corpuscles, which take staining fluids with great avidity. The 

 middle stratum is a clear space in which there is a single layer 

 of large corpuscles, called the cells of Purkinje, 10 to 40 /*. in 



diameter. They 

 are scattered at 

 some distance 

 from each other, 

 and present pe- 

 culiarities pos- 

 sessed by no other 

 cells in the body. 

 The cells are of 

 large size, vary- 

 ing in form from, 

 fusiform to flask- 



Purkin'e 4<$ '~ DiagrRm f the cerebeUar cort 6 ^ showing the large cells of shaped, aCCOrd- 



ing to the plane of 



the section. Their central side is round, and in most cases has 

 no processes. Often the usual rounded contour of the cell- 

 body is broken by an angle, seemingly the remains of a broken 

 process. Here and there a large non-branching axis-cylinder 

 process is seen emerging from the base of a cell and pursuing 

 a course parallel to the cortex. That these basal processes 

 exist in all cases, and ultimately acquire a myelinic sheath, 

 there is no doubt. (See Fig. 146.) 



From the peripheral side large arborescent processes spring, 



