21 8 NORMAL HISTOLOGY. 



the entire depth of the gray matter, five zones or 

 layers may be recognized, which, however, merge 

 into one another. 



In the most superficial layer, the connective-tissue 

 elements preponderate, and among them, delicate 

 nerve-fibrils interlace, and a few small, scattered 

 globular and elongated branching nerve-cells are 

 found ; the second layer is characterized by a great 

 number of small more or less pyramidal cells ; the 

 third and broadest layer contains a proportionately 

 smaller number of ganglion-cells than the second, 

 but they are larger, and, for the most part, pyra- 

 midal, or broad spindle-shaped, and multipolar, with 

 their long axes perpendicular to the surface of the 

 cortex ; in the fourth layer, which is much narrower 

 than the last, are large numbers of small globular 

 and irregular-shaped and branching cells ; the fifth 

 layer, finally, contains medium-sized spindle-shaped 

 cells, with long tapering processes, together with a 

 certain number of smaller irregular-shaped cells. In 

 the third layer, certain of the delicate nerve-fibres 

 begin to take a more regular course toward the 

 white matter; and in the fourth and fifth layers, 

 they are readily seen in distinct bundles passing in- 

 ward between the ganglion-cells. 



b. Cortex of the Cerebellum. In sections through 

 the cortex of the cerebellum perpendicular to the 

 surface, three distinct layers are recognizable : the 

 outer, sometimes called the molecular layer, consists, 



