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ANTIBIOTIC SUBSTANCES—CONTRIBUTION OF THE MICROBIOLOGIST *

Just about five years ago, at the meetings of the Society of American Bacteriologists in Saint Louis, during Christmas 1940, the author was requested to preside over a round table discussion on the subject of the production of antibacterial substances by microorganisms. Both the organizer of that round table, Dr. Dubos, and the proposed Chairman failed to secure enough participants for that two-hour discussion. No better example can serve to illustrate the tremendous progress made in this new branch of science, namely that of Antibiotics, than to point to this Conference which we are about to open. It was, now, not a question what subjects to discuss and what speakers to invite, but to decide what could be left out and who among the numerous workers on this subject were most able to represent the various aspects of this field of research and application. Certain important aspects of the subject had to be left out entirely. It is sufficient to mention, for example, the chemistry of the antibiotics, other than penicillin, the mode of action of antibiotics upon bacteria, the increased resistance of bacterial strains to a given antibiotic, and others. Various sciences have contributed to the development of the science of antibiotics, but none more than microbiology and chemistry. The resulting practical applications have been outstanding, but none has been more important than in the treatment of human diseases. The contribution of the microbiologist to the science of antibiotics has proceeded along four distinct paths, which can be briefly summarized as follows: 1. The Fate of Disease-producing Bacteria that Find Their Way Into the Soil. With the rapid progress of medical bacteriology during the seventh and eighth decades of the last century, fear was expressed that pathogenic bacteria which find their way continuously into the soil may render the latter a source of infections and epidemics. A careful study, therefore, was undertaken of the bacterial population