Elizabeth I. Parsons

Induction of toxigenicity in non-toxigenic strains of C. diphtheriae with bacteriophages derived from non-toxigenic strains.

Summary It has been established that certain bacteriophages derived from naturally occurring non-toxigenic strains of C. diphtheriae will induced toxigenicity in certain non-toxigenic strains of C. diphtheriae as readily as will phages derived from naturally-occurring toxigenic strains.

Susceptibility of Mice to Intracerebral Inoculation of C. Diphtheriae and Diphtheria Toxin

Summary These experiments have revealed four main facts: (a) White mice are highly susceptible to intracerebrally-injected 48-hour broth cultures of rabbit-virulent strains of C. diphtheria; 99% of the mice so inoculated dying within 10 days, (b) Mice are like-wise susceptible, but in somewhat lesser degree, to similar injections of rahbit-avirulent, and hitherto supposedly harmless, strains of C. diphtheria; about 85% of the mice showing highly characteristic reactions within 10 days, (c) Mice receiving minute doses of toxin intracerebrally exhibit the same definitive and fatal results observed in the mice receiving the rabbit-virulent and rabbit-avirulent strains, (d) A number of cultures of diphtheroids (C. xerosis and C. pseudo-diphthericum) were harmless for mice when injected as indicated above. Several other organisms have failed to produce any reactions in any way resembling those produced by C. diphtheria and diphtheria toxin.