Heparin and blood coagulation

Abstract

The preparation of heparin from dog’s liver has been described by Howell and his colleagues in a series of papers (1918, 1922, 1928). The activity of this remarkable substance is such that 1 mg preserves the fluidity of 100 cc blood for 24 hours. Howell’s theory of blood coagulation is based on three properties which he ascribes to heparin. (1) Heparin has no influence on the coagulation of fibrinogen by thrombase,i. e., it does not act as an antithrombase; (2) when added to plasma heparin generates from some unknown precursor in the plasma a considerable quantity of antithrombase; (3) heparin is present in blood and preserves the fluidity of circulating blood by acting as antiprothrombase. In the following pages the actions of heparin on thrombase, thrombokinase, and prothrombase have been determined, and Howell’s theory of blood coagulation has been considered in the light of these experimental facts.