GRAY MATTER OF THE CEREBELLAR CORTEX. 213 



The crura cerebri, pons, and medulla oblongata are composed 

 largely of white matter, or bundles of nerve-fibres passing 

 into the cerebrum and cerebellum, intermingled with tracts of 

 gray matter. 



The ventricles of the brain, continuous with the central 

 canal of the spinal cord, are mostly lined with " ependyma" a 

 single layer of columnar epithelium, ciliated (especially in 

 youth), resting upon a neurogliar basis. The columnar cells 

 are related to the glia-cells. 



In various parts of the brain are found corpora amylacea, 

 minute rounded granules with concentric markings, resembling 

 starch-granules in appearance and chemical reactions. 



The Cerebellum. 



The central portion of the cerebellum is a mass of white 

 matter, within which is an irregular nodule of gray matter, 

 the dentate body. Other nodules of gray matter occur in the 

 upper part of the organ. 



The superficial portion of the cerebellum is divided into 

 branching laminae, which in cross-section appear like the 

 branches of a tree, whence they are called the arbor vitse. 

 These Iamina3 consist of a central core or axis of white matter, 

 covered on each side with gray matter. 



The gray matter of the cerebellar cortex exhibits two well- 

 marked layers, the nuclear layer and the molecular layer, 

 between which is a stratum formed by the bodies of the cells 

 of Purkinje. 



The nuclear or granule layer is a broad zone lying next to 

 and on each side of the central white matter, and contains a 

 crowded mass of small multipolar nerve-cells with prominent 

 deeply staining nuclei and small cell-bodies. Scattered about 

 among these cells are a few larger multipolar nerve-cells and 

 glia-cells, while mednllated nerve-fibres passing into the cen- 

 tral white matter are numerous throughout the nuclear layer. 



The cells of Purkinje, or " antler-cells/' are conspicuous 

 nerve-cells, the bodies of which, separated by intervals, are 

 disposed in a single layer at the junction of the nuclear and 

 molecular layers. Their bodies are very large, rounded or 

 flask-shaped, nucleated, nucleolated, and from their superficial 



