The Relation Between the Growth of Mycobacterium tuberculosis and the Yield of Tuberculin on Synthetic Media.

In the various synthetic media proposed for growing Mycobacterium tuberculosis for tuberculin production, the emphasis has been on finding one which "would yield the greatest amount of growth per unit volume of culture medium in the shortest possible time" (Henley, 1929), on the tacit assumption that the amount of tuberculin produced parallels more or less directly such growth. Thus, Henley and LeDuc (1930), using the weight of organisms produced as a basis of comparison, stated that their ammonium malate medium was somewhat inferior to Henley's asparagine medium. Recently the Committee on Medical Research of the National Tuberculosis Association (White, 1934) adopted a synthetic medium with a high asparagine content for the manufacture of the Purified Protein Derivative (PPD) because it gave "a greater yield in bacilli and production of the desired protein molecule." Substitutes for glycerol in media for tuberculin production have been discarded as unsatisfactory because they yielded fewer organisms. When we reported a synthetic medium from this laboratory (Wong and Weinzirl, 1936) as having the virtue of being inexpensive, we used the weight of organisms produced as the standard of comparison with other media. Recently, however, because of the increased use of tuberculoprotein antigens in immunizing and desensitizing experiments in the Alice McDermott Foundation, we have been led to raise these questions: What is the relation between the weight of