Bacteriology for nurses / [Isabel McIsaac].

  • Isabel McIsaac
Date:
1914
Catalogue details

Licence: In copyright

Credit: Bacteriology for nurses / [Isabel McIsaac]. Source: Wellcome Collection.

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    themselves, but arise from the enzymes or ferments produced by them, A single organism may secrete more than one enzyme, depending upon different conditions of food and temperature. By usage the term putrefaction is used to designate the disintegration (breaking up) of proteid sub- stances, while fermentation is used to denote the dis- integration of the carbohydrates. The bacteria which produce putrefaction are known as saprogenic, and those concerned in fermentations, as in the lactic and butyric acids in milk, butter, cheese, and vine- gars, are known as zymogenic. Bacterial activity produces both acids and alkalies ; the fermentation of carbohydrates producing an acid reaction, and the putrefaction of proteid substances causing an alka- line reaction. In the putrefaction of nitrogenous substances there is not only a complete change in the form of the material but the production of many gases of peculiarly offensive odor, which are believed to be due to the action of the obligatoiy anaerobes. Chromogenic bacteria are those which produce color, the significance of the pigment being little understood. Ptomains and Toxins. — The poisonous products of bacteria are known as ptomains and toxins;
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