Letter from H P Gilding, Medical School, Birmingham to Howard Walter Florey, School of Pathology, Oxford Gives references to papers on permeability - does not have the original pictures - comments on photographs of capillaries which he is enclosing - pleased for Florey to use these - comments on Bowman's drawings of alternating distribution of peripheral arterioles and venules and refers to the hypothesis of a gradient of permeability. 9 May 1952