The differentiation of Bacillus diphtheriae, Bacillus xerosis, and Bacillus pseudo-diphtheriae, by fermentation tests in the serum-water media of HSS / by Arnold Knapp.

  • Knapp, Arnold Herman, 1869-1956.
Date:
[1904]
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Licence: In copyright

Credit: The differentiation of Bacillus diphtheriae, Bacillus xerosis, and Bacillus pseudo-diphtheriae, by fermentation tests in the serum-water media of HSS / by Arnold Knapp. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    In 1897 Neisser^'^ described a method of staining by which, under special conditions, Bacillus diphtheriae showed typical granules, which were said to be absent in Bacillus xerosis. It now seems that this is not the case, the granules being demonstrable in the xerosis bacilli also, but at a later period of their cultural development (Schanz^^). Heiners- dorf,^^ however, never obtained a double stain characteristic of true diphtheria bacilli in sixty cultures of Bacillus xerosis of less than twelve hours' growth. In animal inoculations with cultures and diphtheria anti-toxin (Spronck,^^ quoted from Denny ^'*) the lesions regularly produced by the slightly virulent diphtheria bacilli were prevented, while in the case of inoculations of Bacillus pseudo-diphtheriae and Bacillus xerosis the production of lesions was not prevented. Denny studied the changes in the morphology of these three species during their growth on blood serum, and also the influence exerted on the morphology by variations of temperature, reaction of media, and symbiosis, and found that these species were always indistinguishable morpho- logically at certain stages and under certain conditions. He was, however, able to find distinguishing characteristics if all parallel developmental stages were observed. Schwoner^'^ succeeded in differentiating the diphtheria bacillus and the pseudo-diphtheria bacillus by agglutination in specific sera. The determination of the pathogenicity of these bacilli, and the toxicity of their culture fluids is, however, generally considered the final and only reliable means of differentia- tion. Personal experiments.—The large numbers of xerosis bacilli encountered in a study of conjunctival lesions which was being carried on by the writer led, at Dr. Hiss' sugges- tion, to an investigation of the ability of Bacillus xerosis to ferment sugars with acid production and to a comparison of its fermentative powers with those of the true bacillus diphtheriae and Bacillus pseudo-diphtheriae. The method of study followed has been employed by Hiss