The work of Howard Walter Florey gave the world one of its most valuable disease-fighting drugs, penicillin. Alexander Fleming discovered, in 1929, the mold that produced an antibacterial substance, but was unable to isolate it. Nearly a decade later, Florey and his colleague, biochemist Ernst Chain, set out to isolate the active ingredient in Fleming's mold and then conduct the clinical tests that demonstrated penicillin's remarkable therapeutic value. Florey and Chain reported the initial success of their clinical trials in 1940, and the drug's value was quickly recognized. In 1945, Florey shared the Nobel Prize in medicine or physiology with Fleming and Chain.

Howard Walter Florey was born in Adelaide, Australia. He was one of three children and the only son born to Joseph Florey, a boot manufacturer, and Bertha Mary Wadham Florey, Joseph's second wife. Florey expressed an interest in science early in life. Rather than follow his father's career...