Some quantitative histological observations on the growing cerebellum of the albino rat. (Dimensions of the cortical layers and white core and relative number of Purkinje cells).

: The cerebella of 38 Sprague Dawley rats of various ages have been studied histologically by sectioning in certain parasagittal planes. The age groups were chosen from the early postnatal developmental stage (6, 11 and 16 days), around puberty (41, 46 and 51 days) and maturity (210 days). The sections yielded quantitative data with regard to the dimensions in parasagittal sections, of the entire cerebellum, the cerebellar cortex, the white core, the molecular layer and the granular layer, as well as, the differential and proportional growth of these layers at the above ages. The relative number of Purkinje cells per mm2 of sectional area of the cortex was also determined. The information presented in this study is of indicative value of the pattern of the growing cerebellum and of the ages in which the various layers and the relative number of Purkinje cells assume adult values.