STUDIES IN THE VARIABILITY OF TUBERCLE BACILLI.: II. CORRELATION OF COLONY STRUCTURE, ACID AGGLUTINATION AND VIRULENCE

Abstract

Twenty-eight cultures of tubercle bacilli including human, bovine and avian forms from widely differing sources have been compared as to colony structure, habit of growth in fluid media, acid agglutination and virulence for animals.It was found that the recently isolated highly virulent cultures and all the cultures with a long history of high virulence grew on solid media in S colony form; on fluid media, in the case of bovine and human types, as a continuous veil-like pellicle, in the avian types as a diffuse suspension; all were agglutinated only at a high acidity. All the a virulent or low virulent cultures or those with a history of loss of virulence now grow on solid media in R colonies; in fluid media as a heavy pellicle tending to separate into discrete islands; and are agglutinated at a relatively low acidity.