Letter from G P Gladstone, Bethesda, Maryland to Howard Walter Florey Congratulates Florey on his election as President of the Royal Society - finds his work at Bethesda stimulating - is introducing fluorescent antibody techniques - Zeiss photomicroscope, with fluorescent attachment, is best of those he has used - comments on surveys with Dr Mudd on staphylococcal vaccines - comments on observations on cytopathogenic effect of some staph culture filtrates on HeLa cells. 5 December 1960