Penicillin culture flasks, 1943.
© NMeM / Daily Herald Archive / Science & Society Picture Library
A photograph of penicillin growing in culture flasks, taken by James Jarche for 'Illustrated' magazine. As the penicillin mould grows in the glass flask it develops a distinctive appearance. It grows into a crinkled layer which is called a 'felt'. During this process of growth the mould exudes peniciliin into the growth solution. Each flask contains enough mould to produce a single dose of penicillin. However it takes another three weeks to extract and purify the drug. During the Second World War two British scientists, Sir Howard Walter Florey [1898-1968] and Ernst Boris Chain [1906-1979], developed a means of producing penicillin on an industrial scale. Together with Alexander Fleming they shared the Nobel Prize in 1945. Their work on producing a 'wonder drug' saved millions of lives.