Letter from Howard Walter Florey to R A Kekwick, Lister Institute, Chelsea Bridge Road, London Are working on effects of heparin on the fat and lipoproteins in blood - want to do some quantitative experiments - using rats - cannot use rat serum as a diluent - wonders if Kekwick could supply some of his prepared human serum - only need a little to start with, to see if human material has any effect on rat chylomicrons. 9 July 1952