Abstract
Most of the bacterial strains isolated from the acute oral diseases are streptococci and staphylococci, and a greater part of these bacteria accounts for hemolytic streptococci. Generally speaking, hemolytic streptococci responsible for the incidence of sup-purative diseases in man are chiefly streptococci pyogenes and they are immunologically representated by Group A of the Lancefield's classification. However, those hemolytic streptococci which are found in the oral suppurative diseases differ greatly in terms of their biological properties from the streptococci pyogenes. As a matter of fact, if we except the fact of hemolysis these hemolytic streptococci are very much similar to those in the viridans group. When examined in terms of their antigen, they do not come under any of Lancefield's A, B, C, D, E and F groups and thus they are rich in the strain specificities. In the previously published researches conducted by the author and his collaborators [1-5], many cases were pointed out which gave rise to a suspicion that these hemolytic streptococci might be variationally derived from viridans streptococci that were invariably found in the infected canal or foci of the root inflammation. This thinking has important bearings on the incidence mechanism of the acute oral suppurative diseases and, as a consequence of a series of experiments, the author has been able to devise a method by means of which streptococci viridans can be variationally changed into hemolytic streptococci as follows.
