Physiology and biochemistry in modern medicine . icroseppe (seo page 52); that the cytoplasm Tin: PROPERTIES OF BACH PART OF THE REFLEX ARC 801 is composed of a viscous fluid full of extremely minute granules, each ofwhich apparently consists of a colloidal solution surrounded by a lipoidenvelope (Fig. 210). When the temperature is raised, the granules dis-appear, and when the cells are deprived of oxygen, the cytoplasm andnucleus become swollen. A similar swelling of the cell and nucleus super-venes upon section of the axon; and in stained specimens the Nisslgranules disappear and the protopl
Physiology and biochemistry in modern medicine . icroseppe (seo page 52); that the cytoplasm Tin: PROPERTIES OF BACH PART OF THE REFLEX ARC 801 is composed of a viscous fluid full of extremely minute granules, each ofwhich apparently consists of a colloidal solution surrounded by a lipoidenvelope (Fig. 210). When the temperature is raised, the granules dis-appear, and when the cells are deprived of oxygen, the cytoplasm andnucleus become swollen. A similar swelling of the cell and nucleus super-venes upon section of the axon; and in stained specimens the Nisslgranules disappear and the protoplasm stains diffusely (chromatolysis).In embryonic life the processes of the nerve cells appear to be capa-ble of undergoing a certain amount of ameboid movement, and fibersgrow out from them, indicating, therefore, that in the developmentof the nervous system the nerve cells appear first, and the nerves sub-sequently grow out from them to their proper destination. Prolifera-tion of isolated tissue cells in vitro has been observed for many other. Fig. 210.—Living nerve cells (from the dorsal root ganglia of a dog three days old) examinedby the ultramicroscope. There are no Nissl bodies or neurofibrils, only fine particles, present inthe protoplasm. (From Marinesco.) tissues, such as cardiac muscle, renal epithelium and connective tis-sue. Its occurrence indicates that the therapeutic principle that theaim of treatment should be to give the diseased organ a rest so that bycell regeneration it may recover its lost function, is one which may ap-ply to the nerve tissues of young animals. Whether adult nerve cellsmay regenerate is as yet not certain. This growing out of nerve fibers from their cells is the essential na-ture of the development of the nervous system in the developing birth, unlike the cells of other tissues, those of the central nervoussystem are already provided. No new ones are added during postnatallife. The axons gradually develop from this inherited st
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