Studies have been made to determine possible associations between blood groups and different diseases including cancer of stomach (Aird et aI., 1953; Billington, 1956; Buckwalter and Scoy, 1961), duodenal and gastric ulcers (Aird et aI., 1954; Roberts, 1957; Wallace et aI., 1958,’ Clarke et al.; 1959; Buckwalter and Scoy, 1961), pernicious anaemia (Callender et aI., 1957), rheumatic fever (Glynn et aI., 1956; Clarke et aI., 1960). salivary gland tumours (Ca…