Hand-book of dental anatomy and surgery : for the use of students and practitioners / by John Smith.

Date:
1871
Catalogue details

Licence: Public Domain Mark

Credit: Hand-book of dental anatomy and surgery : for the use of students and practitioners / by John Smith. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    cells were regarded as minute vesicles having a wall enclosing a cavity in which were fluid con- tents and a nucleus. Later researches, how- ever, have shown that what were originally termed cells have in many cases no title to be so denominated, as what is now known of such bodies shows them to be often merely little masses of what is termed protoplasm with or without a nucleus (37). This protoplasm is a substance possessing the peculiar vital properties essential to living bodies—namely, the power of spontaneous movement, nutrition, growth, and reproduction of its own kind. Both the nucleus and protoplasm are generally products of the division of similar constituents of another cell. The protoplasm itself is structureless, but may contain various substances, and in this way the cell becomes differentiated from others. Thus when containing oil granules, it becomes a fat cell —pigment, a pigment cell—calcareous salts, a bone cell, &c. Much diversity exists in the func- tions performed by cells, and their multiplicity of form is no less remarkable. The origin, de- velopment, nutrition, functions, and death of cells, would occupy much greater space, how- ever, than can possibly be here devoted to these