The need for continuous administration of anticoagulants became apparent early in the clinical use of these drugs.* As a result of experience gained in the treatment of patients with rheumatic heart disease and recurrent embolization, we suggested in 1946 that these patients be maintained on anticoagulants. In 1949 our group reported on the management of 19 patients with long-term therapy.3 Additional reports by Nichol and Fassett,4 Cosgriff,5 Askey and Cherry,6 Bay and co-workers,7 and Tulloch and Wright8 have confirmed the favorable impression reported earlier, and the technique of long-term anticoagulant therapy is being increasingly employed. At the International Conference on Thrombosis and Embolism, at Basle, Switzerland, July, 1954, Catherine C. Burt, of Edinburgh; P. A. Owren, of Oslo; J. Dedichen, of Oslo; J. Beaumont, of Paris, and others reported similar results. CLINICAL MATERIAL AND DOSAGE The total number of patients we have followed on