William Fowler, Caversham, to Dale Saying how much he enjoyed their meeting, and describing early tests on guinea pigs using diptheria antitoxin and the failure of the diptheria bacillus to grown in a broth contaminated with mould: 'Pity we didn't think of filtering off the broth beneath the mould & testing it for antibacterial substances - it seems such an obvious thing to do now & might have anticipated Fleming's work by quite a number of years'. Also recalling observations on the settlement rate of red corpuscles from the blood plasma of a horse having a high content of diptheria antitoxin 2 September 1960