Elements of bacteriology for practitioners and students : with especial reference to practical methods / by S.L. Schenk ; translated from the German (by the author's permission) with an appendix / by W.R. Dawson.

  • Schenk, Samuel Leopold, 1840-1902.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Elements of bacteriology for practitioners and students : with especial reference to practical methods / by S.L. Schenk ; translated from the German (by the author's permission) with an appendix / by W.R. Dawson. Source: Wellcome Collection.

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    luminous in the dark (phosphorescence), in consequence of the molecular activity of their protoplasm. Influence of bacteria on the tissues.—The influence which bacteria exert on the tissue of the bodies of men and animals depends both on the qualities of the bacteria and on the nature of the tissue. The action of the jDathogenic bacteria is not alike in all animals, and those which are insusceptible to certain bacteria are said to be immune in their relation to those particular organisms. Animals, however, which are commonly immune towards a patho- genic micro-organism may, under altered conditions, lose their immunity; for example, the frog, although usually immune to anthrax, becomes susceptible to it at a higher temperature. The virulence of pathogenic bacteria may be diminished by various factors, amongst which are included sojourn m the body of immune animals, increased atmospheric pres- sure, the action of higher degrees of temj)erature, the influence of sunlight, &c. This weakening is dependent on an alteration in the products of metabolism. Toxins, toxalbumins, and ptomains.—As products of the metabolism of those bacteria which efi’ect an entrance into the body substances are formed, some of which exert violent toxic action, and which are divided into toxins and ])tomains, or cadaveric alkaloids, and to these is ascribed the action of the pathogenic bacteria in originating morbid processes. The toxins are further subdivided hito tox- albumins and proteins. Toxalbumins are albuminoid bodies formed during the gi’owth of the bacteria upon culture-media, especially in bouillon. Their activity depends upon certain definite degrees of temperature, and they decompose at the boiling- point. Our knowledge of them is due to the researches of Koux, Yersin, Brieger, and C. Fraenkel.