Kirkes' handbook of physiology. / By W. Morrant Baker and Vincent Dormer Harris.
- William Senhouse Kirkes
- Date:
- 1888
Licence: Public Domain Mark
Credit: Kirkes' handbook of physiology. / By W. Morrant Baker and Vincent Dormer Harris. Source: Wellcome Collection.
Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.
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![CHAP. I.] THE rilOPERTIES OF PllOTOl'LASM. cells it was called Protoplasm by Mulder, while Kemak applied the same name to the substance of animal cells. As the presumed formative matter in animal tissues it was termed lllastcma, and in the belief that, wherever found, it alone of all substances has to do with generation and nutrition, Beale has named it Germinal matter or Hiojda-im. Of these terms the one .most in vogue at the present day, as we have already said, is Protoplasm, and inasmuch as all life, both in the ainmal and vegetable kingdoms, is associated with protoplasm, we are justified in describing it, with Huxley, as the physical basis of life, or simply living matter. A cell may uow be defined as a nucleated mass of protoplasm,* of microscopic size, which possesses suflicient individuality to have a life-history of its own. Each cell goes through the same cycle of changes as the whole organism, though doubtless in a much shorter time. Beginning with its origin from some pre- existing cell, it grows, produces other cells, and finally dies. It is true that several lower forms of life consist of non-nucleated protoplasm, but the above definition holds good for all the higher plants and animals. Hence a summary of tlie manifestations of cell life is realty an account of the vital activities of protoplasm. Protoplasm.—-Physically, protoplasm is viscid, varying from a semi-fluid to a strongly coherent consistency. Chemically, living protoplasm is an extremely tmstable albuminoid substance, insoluble in water. It is neutral or weakly alkaline in reaction. It undergoes heat stiffening or coagulation at about 130° F. {54'5° t^ )) ii-nd hence no organism can live when its own tempei'a- ture is raised beyond this point. Many, of course, can exist for a time in a much hotter atmosphere, since they possess the means of regulating their own temperature. Besides tlie coagulation produced by lieat, protoplasm is coagulated and therefore killed by all the reagents which pro- duce this change in albumen (sec Appendix). If protoplasm be subjected to chemical analysis, the cliicf substances of which it is found to consist belong to the class of bodies called Profeiih or albumins. These iire bodies made up of the chemical elements (J. H. N. 0. and S., in certain sliglitly varying ])ropor- tions. They are essential to the formation of protoplasm, for * In the human body the cells range from the red blood-cell (vji-,,-, in.) to the ganglion-cell (^'^ in.). n 2](https://iiif.wellcomecollection.org/image/b24757226_0027.jp2/full/800%2C/0/default.jpg)
