What was the title of the journal in which Fleming published his penicillin discovery?

Fleming published his discovery of penicillin in the British Journal of Experimental Pathology. His 1929 paper was titled “On the antibacterial action of cultures of a Penicillium, with special reference to their use in the isolation of B. influenzae.”

The publication followed Fleming's famous observation in 1928 that a mould contaminating a staphylococcus culture had destroyed the bacteria around it. He identified the active substance as penicillin and investigated its antibacterial action, but the paper attracted little attention at first. Producing and purifying penicillin in large quantities proved exceptionally difficult.

The breakthrough came later through the work of Howard Florey, Ernst Chain and their Oxford colleagues, who developed methods for purification, testing and mass production. Fleming's 1929 article is therefore the original publication associated with the discovery, while later research made penicillin a practical medicine. Nature and The Lancet published other important medical and scientific work by Fleming, but not this original discovery paper.