Despite many experimental and clinical investigations, knowledge of the exact nature of the substances and reactions involved in the process of coagulation of the blood is still incomplete. Information concerning the defects of coagulation present in such conditions as hemophilia, jaundice and purpura is even more deficient. Until these fundamental defects are elucidated it is evident that the treatment of these conditions must remain empiric and that the prognosis for any given patient will continue to be uncertain.
Eagle1 has recently summarized the available evidence on the clotting mechanism and supported the theory that the formation of a blood clot is the result of two basic reactions. The first is the reaction between prothrombin, calcium and a tissue or platelet derivative (thromboplastin) to form thrombin; the second, the action of thrombin on fibrinogen to form fibrin. A substance, antithrombin, normally present in the circulating blood, or heparin, prepared artificially