The Distribution of Diphtheria Bacteriophage *

For the past three years a study of bacteriophage in its relation to Bact. diphtheriae has been in progress in this laboratory. Incidental to this study observations have been made on the occurrence of the lytic principle active upon this bacterium, with results which somewhat extend our knowledge of the distribution of bacteriophage in general, for it would hardly seem that the conditions governing Bact. diphtheriae bacteriophage should be unique and not be duplicated in the case of bacteriophage races of other potentialities. That bacteriophage is more or less widely disseminated throughout nature has, of course, been observed, but in no instance has any considerable attention been paid to the distribution of a given type of bacteriophage active upon an organism of known pathogenic power. Reports are available as to the recovery of B. coli bacteriophage from a variety of sources, of staphylococcus bacteriophage from other sources, of B. pestis bacteriophage under other conditions, etc., the general conclusion being that certain races of bacteriophage are to be found in connection with normal man and with materials intimately associated with him, in contaminated soils and waters, and in actual infectious processes. Furthermore, numerous reports attest to the fact that many bacterial cultures may harbor, for long periods of time, specific races of bacteriophage. How this is effected is, perhaps, aside from the question, for at the moment we are not concerned with the problem as to whether this represents a symbiotic growth of two autonomous organisms, or whether the bacteriophage which characterises such cultures represents a derivative of the culture itself. The only pertinent fact is that thus far, with the exception of Bact. diphtheriae, no organism has been described as being uniformly and constantly associated with bacteriophage. As has been previously reported, sporadic attempts have been made in this laboratory for the past ten years to isolate a bacteriophage active upon Bact. diphtheriae, but until recently all had failed. This was, of course, due to the fact that a known bacteriophage-susceptible strain of the diphtheria bacillus was lacking, and,