Abstract
Antagonism between Actinomyces and bacteria has been observed by many workers, and the literature is reviewed by Waksman (1) . But it is rather recently that the antibiotic substances are extracted and purified up to the crystalline forms. According to the review by Kiese (2), Actinomycin A is the first crystalline antibiotic substance from Actinomyces.
Since we had begun to study the antibiotics from Actinomyces (January, 1946), the red crystalline antibiotic substance was first extracted. And owing to the contradictory descriptions in the reviews by Kiese (2), and by Hallauer (3), it could not be decided whether this substance was identical with Actinomycin A, until we had a chance to read the monograph concerning the antibiotics written by Waksman (4) .
