Sir John Vivian Dacie, FRS (20 July 1912 Putney, London – 12 February 2005)[1] was a British haematologist.
During World War II (1943–1946) he served in the Royal Army Medical Corps, ending up a lieutenant colonel.
[5] He founded the Leukaemia Research Fund, Great Ormond Street, London (1960).
[1] He discovered and named Christmas disease, more commonly referred to as haemophilia B, a deficiency of coagulation Factor IX.
[citation needed][3][6] Sir Dacie is credited with characterizing the relationship between paroxysmal nocturnal hemoglobinuria and bone marrow failure syndromes like aplastic anemia.