Discovery of the Blood Clotting Mechanism

Understanding of how blood clots built up over more than a century of separate findings. Johannes Muller described fibrin in the first half of the nineteenth century, and Rudolf Virchow named fibrinogen, the protein from which it forms. Alexander Schmidt proposed later in the nineteenth century that clotting proceeded through an enzymatic conversion and introduced the terms thrombin and prothrombin, Nicolas Maurice Arthus showed in 1890 that calcium was necessary for clotting to occur, and Paul Morawitz brought these findings together into a tissue factor theory of coagulation in 1905. Through the twentieth century researchers identified a further series of clotting factors, and in the 1960s R. G. MacFarlane in Britain and Earl Davie and Oscar Ratnoff in the United States independently proposed the cascade model that describes clotting as a chain of enzymes activating one another in sequence.