American Red cross textbook on elementary hygiene and home care of the sick / by Jane A. Delano and Isabel McIsaac.

  • Jane Delano
Date:
1913
Catalogue details

Licence: In copyright

Credit: American Red cross textbook on elementary hygiene and home care of the sick / by Jane A. Delano and Isabel McIsaac. Source: Wellcome Collection.

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    Spores.—Following a favorable period of repro- duction certain bacteria enter into a stage known as spore-formation, which is characterized by the development of round or oval glistening bodies (spores) which are of dense structure and possess an extraordinary degree of resistance to heat, chemicals and other injurious materials. Except in rare instances a single cell produces but one spore. The stage of spore-formation is a resting stage and the stage of reproduction is known as the vegetative Fig. 5.—Bacteria with Spores. (Williams.) stage. As soon as favorable conditions of tempera- ture, moisture and food return, the spores again develop and take on the vegetative state, but the spore may remain dormant for months or years, a fact which is of peculiar significance in the con- sideration of certain infectious diseases. Where Bacteria are Found.—Bacteria are found everywhere; wherever dust and air find their way bacteria are present. In the minutest crevices too small to be seen by the naked eye, like those in the
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