Protoplasm : its definition, chemistry and stucture / by Gustav Mann.
- Gustav Mann
- Date:
- 1906
Licence: In copyright
Credit: Protoplasm : its definition, chemistry and stucture / by Gustav Mann. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![excuse me for having included the nucleo-proteids in my discussion. Before attempting to give a definition of the word proto- plasma, it is my intention to outline in the first instance our chemical and physico-chemical knowledge regarding the units out of which we believe protoplasm to be built up'. In protoplasm we have certain organic units which have received a great deal of attention, and also inorganic con- stituents which are greatly neglected. However much from a purely chemical point of view the isolation of the organic constituents is desirable, we should never forget, as I pointed out in 1902*, ‘that so-called pure ash-free albumins (proteids) are chemically inert, and, in the true sense of the word, dead bodies.’ For descriptive purposes Proteids [Protein-Substanzen; Substances albuminoides] may be divided into three groups. 1. Albumins which occur in nature as ‘ native albumins.’ They include the ‘albuminoid’ substances which form the supporting or connective tissues of the animal body. 2. Proteids proper, which are combinations of the native albumins with such other organic compounds as sugars or radicals containing phosphorus or iron. 3. Derivatives of the natural albumins and proteids, which retain in their chemical configuration the char- acteristics of albuminous substances, and are repre- sented by the albumoses, peptones, peptids, and other compounds. These bodies are met with in nature as products of digestion and metabolism, but they may also be obtained artificially by hydrolysis of the more complex albuminous substances. On subjecting these compounds to the action of acids or * The author has given full references in his Text-book on the Chemistry of Proteids, Macmillan & Co., 1906, p. 606. > Mann, Physiological Histology, 1902, pp. 2, 25, 224, 338, 345, 348-](https://iiif.wellcomecollection.org/image/b22471303_0008.jp2/full/800%2C/0/default.jpg)
