Brief biography -- for popular consumption -- of the new drug which has proved less harmful and more potent than the sulfas --written by a medical popularizer. The conception of the bacteriocidal idea in Metchnikoff's laboratory; its discovery and description as penicillin, a mold, in 1928 by an English Dr. Fleming; its recultivation here in 1939 and the first proofs of its effectiveness; the almost immediate production of the mold on widening scale -- its current values and futures. Some rhetoric, some padding -- but an adequate job.