On the antibacterial action of cultures of a penicillium, with special reference to their use in the isolation of B. influenzae.

Discovery of the growth-inhibiting action of Penicillium on certain bacteria. 

In 1945 Fleming shared the Nobel Prize in Physiology or Medicine with Ernst Boris Chain and Sir Howard Walter Florey "for the discovery of penicillin and its curative effect in various infectious diseases." See also Nos. 10784 and 12599.