| Description | Thanks for non-coloured penicillium - Heatley is going to try out these cultures - simpler to purify if no pgment present - hopes to have enough penicillin to try clinically soon.
On verso of letter from Fleming to Florey, 15 November 1940: Sorry to have been so long in sending penicillium cultures - solid penicillin seems to be, weight for weight, much more potent than the most powerful sulphonamides on the ordinary septic microbes [if chemists purify active principle and synthesise it sulphonamides will be beaten. |