A photograph of a culture flask growing penicillin, taken by James Jarche for 'Illustrated' magazine in 1943. 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. In 1934, Odhams, publishers of the Daily Herald, launched the magazine 'Weekly Illustrated'. Based on European ideas of photoreportage it was the first British picture magazine. In 1939 the magazine changed its name to 'Illustrated'. It continued to be published until 1958.
© Daily Herald Archive / National Science & Media Museum / Science & Society Picture Library