Bacteriology for nurses / [Isabel McIsaac].

  • McIsaac, Isabel
Date:
1914
Catalogue details

Licence: In copyright

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

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    9 and the spiral. The rods are known as bacilli (sing, bacillus), the spheres as cocci (sing, coccus), and the spirals as spirilla (sing, spirillum). More baccilli are known than any other form, and cocci are much more numerous than spirilla. Long-continued growth in artificial media some- times causes abnormal forms of growth, just as unnatural surroundings and conditions produce deformities in the higher forms of life. Structure.—The internal structure of bacteria is exceedingly simple: there appears to be a mem- branous covering, including the protoplasm (ger- minal matter), which is not always clearly discern- ible, but in some species (micrococcus of pneumonia) may be seen as a sharply defined capsule inclosing a clear zone. The nature of the cell-substance is still imper- fectly understood; the question of the existence of a nucleus and the significance of the internal structure are still disputed points which present one of the exceeding difficulties of which Muller wrote in 1786. Motility. — The power of motion in certain species of bacteria is due to hair-like appendages, or flagella, which by a lashing movement enable them to move through fluids. The flagella vary in their position