Penicillin injection, World War II. Army medical personnel injecting a patient with a dose of the antibiotic drug penicillin. A tray of sterile equipment is at right, with the patient at left. Penicillin had been discovered in 1928, but was not widely used as an antibiotic until its mass production for the US Army in World War II. Use of penicillin by the US Army saved many thousands of lives during the war. This field hospital is on Labuan Island, northern Borneo. The liberation of this island from the Japanese by US and Australian forces began on 10 June 1945, part of the Battle of North Borneo, codenamed Operation Oboe Six. Photographed on 17 June 1945.