1881-1955. Scottish bacteriologist who
discovered the first antibiotic drug,
penicillin, in 1928 (but it did not come into
use until 1941). In 1922 he had discovered
lysozyme, an antibacterial enzyme present in
saliva, nasal secretions, and tears. While
studying this, he found an unusual mould
growing on a neglected culture dish, which he
isolated and grew into a pure culture; this
led to his discovery of penicillin. In 1945
he won the Nobel Prize for Physiology or
Medicine with Howard W Florey and Ernst B
Chain, whose research had brought widespread
realization of the value of penicillin.