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The Scientific Method. Dr. Fleming stuck a loop of platinum wire into the mold colony, dipped the wire into some mold-growing liquid in a test tube. In less than a week, there was a felt-like growth at the mouth of the tube and a half-inch of cloudy liquid below it. To Dr. Fleming's amazement, the liquid in which the culture grew, even when diluted 800 times, prevented staphylococci from growing at all: "It was therefore some two or three times as strong in that respect as pure carbolic acid."
Soon Dr. Fleming had ascertained that: 1) the strange liquid did not harm fresh leucocytes (white blood corpuscles); 2) injections of the liquid did not hurt mice; 3) some bacteria (e.g., whooping cough bacillus) lived in the liquid as cozily as in a baby's throat. Modest Dr. Fleming saved the moldy plate as a souvenir, still has it.
Next year what Dr. Fleming knew about the mold's bacteria-baiting by-product appeared in the British Journal of Experimental Pathology. He had found out that the mold was some kind of Penicillium (from the Latin for pencil—the shape of the magnified mold). He named its byproduct penicillin.
The Man. Alexander Fleming was born (1881) in Darvel, in Ayrshire, the son of a farmer. He went to St. Mary's Hospital Medical School, largely because it won the Rugger cup and had had a championship swimming team the year before. (Dr. Fleming still loves to swim. His other hobby is rifle shooting.) When he graduated in 1908, he took honors in physiology, pharmacology, medicine, pathology, forensic medicine and hygiene, received the University Gold Medal.
He went to work immediately in St. Mary's pathology laboratory under Sir Almroth Wright, now 83, pioneer in vaccine therapy and grand old man of British Medicine. Sir Almroth whetted young Fleming's interest in the mysterious destruction of bacteria by white blood corpuscles and the problem of antiseptics. As a captain in the medical corps in France during World War I, Dr. Fleming noticed that the antiseptics then in use (chiefly Carrel-Dakin's solution) hurt the white blood corpuscles even more than they hurt bacteria. In some cases the antiseptics promoted infection by destroying the body's own defenses.
After the war, Dr. Fleming went back to the peaceful laboratory and teaching routine which he still follows. He held classes, ate his lunch in St. Mary's gloomy refectory, where diners are served soup, "cut off the joint and two veg," rice pudding, prunes, and tea for one shilling sevenpence. Sometimes at the end of the day he went across from the hospital to The Fountains, a potted-palm pub in Praed Street, for a glass of beer before going home to spend the evening with his wife and son (now a medical student at St. Mary's). Now & again he would write a scientific paper.
Guiding Idea. One idea ran through all his work: he would look for some naturally occurring bacteria-fighter (new term: antibiotic substance) that would not harm animal tissue. The first antibiotic Dr. Fleming found was lysozyme. It occurs in tears and egg white, can dissolve some bacteria, most of them harmless. That was in 1922—six years before the day when he first saw and grasped the meaning of the sterile ring around the penicillium mold.