ABSTRACT
The following account of the discovery and first clinical development of heparin was recorded by the physiologist Charles H. Best (1959), a codiscoverer of insulin as well as a pioneer in studies of heparin. Incidentally, in 1916, while working at Johns Hopkins University to characterize procoagulant substances, Dr. Jay McLean (1916) identified a natural anticoagulant substance. Further studies of this material were performed by his supervisor, Dr. Howell, who coined the term, "heparin" to indicate its first extraction from animal hepatic tissues (Gr. 'l1 'ITUp [hepar], liver) (Howell and Holt, 1918). Despite its in vitro anticoagulant action, the inability of heparin to prevent platelet-mediated thrombosis (Shionoya, 1927) made it uncertain whether it had antithrombotic potential. However, animal (Mason, 1924) and human studies (Crafoord, 1937) showed that heparin could prevent thrombosis. By the 1950s, heparin was established as an important therapeutic agent in the treatment of venous and arterial thrombosis.
