Coccal forms of the diphtheria bacillus / H.J. Parish.

  • Parish, H. J. (Henry James)
Date:
[1927?]
Catalogue details

Licence: In copyright

Credit: Coccal forms of the diphtheria bacillus / H.J. Parish. Source: Wellcome Collection.

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    * COCCAL FORMS OF THE DIPHTHERIA BACILLUS. H. J. PARISH. Wellcome Physiological Research Laboratories, Beckenham, Kent. Received for publication March 30th, 1927. For several years diphtheria toxin, prepared from the “Park and Williams No. 8 ” strain of G. diphtheria, has been used for the immunization of horses at these laboratories. From time to time smears of broth cultures of this organism used for toxin production have contained coccoid forms resembling micrococci, although irregularity in outline or staining, or the presence of intermediate forms between bacilli and cocci, has usually suggested a bacillary origin. These cultures of doubtful purity, when plated on Loefher’s blood- serum, have shown only characteristic dome-shaped colonies consisting entirely of bacilli. Coccoid forms of diphtheroids have been described by Mellon (1917). Heinemann (1917) noticed the replacement of typical bacillary forms by coccus forms in certain of his cultures on beef, veal or horse-meat broth. His coccus-like growths produced similar toxin to his bacillary forms but of relatively low potency. On Loefflers’s blood-serum and veal glucose agar 1