On the Production of Antitoxin by the Injection of Filtrates of Cultures of Non-virulent Diphtheria Bacilli

Abstract

We are still in doubt regarding the exact position of those bacilli which, morphologically and culturally, appear to be identical with the Klebs-Loeffler bacillus but which differ from it only in the absence of specific pathogenic power for laboratory animals. Most writers regard such non-virulent strains as true diphtheria bacilli which have lost their virulence and toxigenic power either temporarily or permanently. Others however are inclined to place them in a group allied to that of the genuine Klebs-Loeffler bacillus and express doubts as to whether they at any time possessed a claim to pathological significance (Graham Smith, 1904).