What phrase did Fleming reportedly say on seeing the contaminated plate?

Alexander Fleming reportedly said “That’s funny” when he saw the contaminated culture plate. The plate contained staphylococci, but a blue-green mould had grown on it; the bacteria immediately surrounding the mould had been destroyed while colonies farther away continued growing.

Fleming encountered the plate at St Mary’s Hospital in London on 3 September 1928, after returning from holiday. His observation led him to investigate the mould’s antibacterial substance, which he named penicillin in 1929. The mould was long identified as Penicillium notatum or P. chrysogenum, but later genetic work identified Fleming’s strain as Penicillium rubens.

The remark is often presented as a perfectly preserved quotation, but “reportedly” matters: the famous wording comes from later recollections and historical accounts. Fleming’s discovery was only the beginning. Howard Florey, Ernst Chain, Norman Heatley and colleagues at Oxford later developed methods to purify and produce penicillin in useful quantities. Fleming, Florey and Chain shared the 1945 Nobel Prize in Physiology or Medicine.