Textbook of normal histology: including an account of the development of the tissues and of the organs . ddle of the formatio reticularis, on either side of the raphe, lies aconspicuous group of large pigmented nerve-cells, the tegmental orred nucleus, so called on account of its brown or reddish hue. Theformatio reticularis of the tegmentum differs little from the similarstructure at lower levels. In general, the fibres contained withinthe crusta pass to the striatum and to the cerebral cortex,while those of the tegmentum usually terminate in or about thethalamus. THE CEREBELLUM. The cerebell


Textbook of normal histology: including an account of the development of the tissues and of the organs . ddle of the formatio reticularis, on either side of the raphe, lies aconspicuous group of large pigmented nerve-cells, the tegmental orred nucleus, so called on account of its brown or reddish hue. Theformatio reticularis of the tegmentum differs little from the similarstructure at lower levels. In general, the fibres contained withinthe crusta pass to the striatum and to the cerebral cortex,while those of the tegmentum usually terminate in or about thethalamus. THE CEREBELLUM. The cerebellum consists of a peripheral or cortical layer of graysubstance which encloses the various tracts of nerve-fibres composing THE CENTRAL NERVOUS SYSTEM. 305 the white matter of the medulla, together with certain additional gray-nuclei embedded within the latter. On section, each leaflet of thecerebellum is seen to be made up of (1) a central core of whitemedullary substance, which blends into (2) the granule layer,characterized by its rust-color, external to which follows (3) the Fig. Section of human. ment: iv, white matter of medulla ; g,o, granule and molecular or outer layer, between which lies layer of Purkinjes cells (/). outer or molecular stratum ; between the latter and the granulelayer lies (4) the single row of ganglion-cells which constitutes thelayer of the cells of Purkinje. The granule layer forms a zone conspicuous on account of thegreat number of small deeply-staining cells which it contains. Itvaries in thickness, being broadest at the summit,of the laminaeand narrowest at the bottom of the fissures. Towards the outerlayer the zone is sharply defined, but it fades away on the medianside into the medullary substance. The nerve-cells of the granule layer are of two kinds,—thesmall and the large ganglion-cells. The former are small (6-7 ft)round elements, stain deeply, but possess so little protoplasm thatthe greater part of the cell is formed by the nucleus. The


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Keywords: ., bookauthorpiersolgeorgeageorgea, bookcentury1800, bookdecade1890