“Bacillus anthracoides.” A Study of its Biological Characters and Relationships and its Pathogenic Properties under Experimental Conditions

Abstract

1. There occurs in nature an organism belonging to the group of Gram-positive aerobic sporing bacilli which closely resembles B.anthracis, especially in its cultural characters.2. These organisms occur commonly in materials that are frequently examined for the presence ofB. anthracis.3. TheB. anthracoidesis pathogenic to guinea-pigs and mice under experimental conditions, and would appear to occupy a position between the virulentB. anthracisand the non-pathogenic members of the group of aerobic sporing bacilli, e.g.B. subtilis, B. mesentericus.4. Subcutaneous injection of cultures ofB. anthracoidesproduces a local inflammation with gelatinous oedema and a fatal septicaemia.5. Only large doses of living organisms are lethal and attempts to increase the virulence of this organism by various methods have not proved successful.6. Individual animals vary considerably in their resistance to the organism.7. With the exception ofB. anthracis, theB. anthracoidescontrasts with the other members of the group in its pathogenic properties under experimental conditions. Twenty-five strains of this organism have been isolated, each of which possesses pathogenic properties. The pathogenicity of 49 strains of other representatives of the group has been tested, and only one of these was found to have lethal effects.