A Study of Some of the Factors Promoting Dissociation of Bacterium dysenteriae, Sonne

Abstract

Bact. dysenteriae Sonne was aged in various liquid media. The erosive phenomenon of Preisz was observed. The G colony form is apparently rare; it was observed only twice in 48 cultures studied, and was obtained only after plating out old cultures. A filterable form could not be demonstrated by filtration (Berkefeld N, W and Seitz filters) of cultures in which variation was taking place, as shown by formation of different forms of colonies on agar plates. Filtrates were subcultured in various media, and Hauduroy''a technic of serial transfer on lactose agar was also used. All subcultures were negative and no evidence could be found of a gradual development or "growing out" of a filterable form.