At St Mary's Hospital, London (England) in 1928, Scottish bacteriologist Alexander Fleming discovered Penicillin. This important discovery was the breakthrough for which doctors and chemists had been searching for many years - a way of treating sick people which would kill germs but not harm their patients.
In the past doctors had found that substances such as quinine, iodine and arsenic had killed the germs, but if they were administered incorrectly or in a large dose the patients could also be poisoned.
Penicillin was discovered when a small mould speck fell into a Petri dish containing Staphylococci bacteria (this causes boils and blood poisoning) which Fleming was growing. He noticed that where the mould had fallen, the groups of germs around it were dying off.
Fleming grew the mould in a sugary broth and then filtered it, and the liquid it produced he called Penicillin. When tested, it was found that Penicillin stopped the growth of the bacteria which caused diptheria, pneumonia and sore-throats. It was the first of the many drugs (later to be called antibiotics) which attacked and killed germs but did not harm body tissues.
