Experiments with Isonicotinic Acid Hydrazid.
—The study of the antituberculous activity of isonicotinic acid hydrazid (isoniazid) is one of the most important problems at present in Japan. The production of this drug has been conducted by many Japanese pharmaceutical firms. Sanatoriums and laboratories are now studying its effectiveness. In spite of its excellent bacteriostatic activity against Mycobacterium tuberculosis in vitro, the growth of tubercle bacilli of the specimen from tuberculous patients is not so clearly inhibited as in the case of streptomycin. Many experiences show that a certain concentration of streptomycin inhibits the growth of all tubercle bacilli, while isonicotinic acid hydrazid generally inhibits it even in lower concentration; but sometimes a few colonies appear that do not inhibit the growth of bacilli in the same or higher concentration of the drug as compared with streptomycin. The results of the animal experiments are nearly the same as those in other