Sir Alexander Fleming Background When Sir Alexander Fleming treated a large number of soldiers who got injured as an army surgeon, he noticed that antiseptic solution was not useful. In the first World War, the wounded had festering wound, and the medicine of that time, no one able to cure it. Therefore, he began to research on the disinfectant material. He cultured many bacteria and repeated an experiment. One day tidying his messy room, he found that green mold spread on the medium which cultured bacteria. It happened by mistake. He left the cover of the bottle of the medium. At that time, he noticed that bacteria disappeared around the green mold. He thought that the green mold may have an ingredient which had killed bacteria. Research Question Does the green mold sterilize bacteria? Methods and Data In 1928, Fleming found that green mold killed bacteria. He diluted a filtrate of the mold because he was not able to isolate penicillin. In 1928, he found that applying a penicillin was effective for the treatment. In 1940, H.W.Florey and E.B.Chain succeeded in an isolation of penicillin. In addition, they gave penicillin to the mouse which infected a staphylococcus and succeeded in treatment of mouse. In 1941, they gave penicillin to a patient who was infected with bacteria and fatally wounded, an effect was confirmed. Conclusions Penicillin was one of the medicines saved the most lives. However, the war against bacteria hadn't finished. The new bacteria, resistant bacteria were appeared. It was tolerant of antibiotics. Bacteria evolve and get antibiotics whenever people produce new antibiotics. The war against bacteria will have continued for the future.