Toxin and reaction changes produced by the diphtheria bacillus in culture / by Percival Hartley and Olga Mary Hartley.

  • Percival Horton-Smith Hartley
Date:
[1922?]
Catalogue details

Licence: In copyright

Credit: Toxin and reaction changes produced by the diphtheria bacillus in culture / by Percival Hartley and Olga Mary Hartley. Source: Wellcome Collection.

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    media used in the experiments described below contained the fermentable substances normally occurring in muscle infusion, no attempt being made to remove these by preliminary treatment with B. coli or other organisms. As will be seen from the accompanying charts the curves showing reaction change during growth are of the same general type, and resemble very closely those recorded by Bunker. In all twelve cases the reaction curve was typical and toxin was formed; in ten out of the twelve cases high-grade toxin was produced at some stage of the experi¬ ment. The opportunity to study toxin formation in media in which the reaction curve was atypical did not occur. Bunker studied the daily reaction change and toxin formation in media containing twenty different kinds of peptone, and plotted the results on a common scale; from this it was evident that the strongest toxins had occurred at a given range of PH values on the respective curves, and he concludes “ that it would be possible to establish a zone which would include all the strong toxins and outside of which no potent toxin would occur. This zone was arbitrarily fixed by inspection as lying approximately between BH 7'85 and PH 8*25.” The significance of this conclusion is apparent. One of the chief difficulties en¬ countered in routine work is to ascertain the time when toxin should be harvested. Bunker’s work indicated a way in which this particular difficulty might be overcome. When Bunker’s paper appeared we were engaged in a study of the same subject on somewhat similar lines, but as some of our results differed from his, the experiments were repeated and extended with the object of following the daily changes in reaction and toxin production. Preliminary observations had indicated that reaction change and toxin production were influenced by three factors at least, viz., the peptone, the strain of the bacillus, and the volume of medium inoculated (and hence the size of container used). Bunker, indeed, points out that these are factors of importance which affect the results, but as the study of the phenomenon has yielded with us results which differ in some respects from his, a brief account of some of our experiments is given below. Method of Experiment. Bottles (capacity 500 c.c. or 5000 c.c.) cylindrical in shape, were used as containers. The smaller bottles contained 100 c.c. of medium, the larger ones 1000 c.c. After inoculation, samples were withdrawn aseptically at the end of 1, 2, 3, 4, 5, 7, 9 and 11 days, a smear being made and examined for morphology, contaminations, etc. To each sample withdrawn 0'5 per cent, carbolic acid was added, and after standing for twenty-four hours in the dark the PH and toxicity were determined. From the data thus obtained, curves were plotted showing reaction change and toxin production during the course of each experiment. The intracutaneous method of Rdmer and Sanies (19094), as developed by Glenny and Allen (19213) in these laboratories was used for determining the toxicity of the different samples. Without the use of this method the expenditure A 2
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