Abstract
The action of purified thrombin on a preparation of antihemophilic factor with fibrinogen has been studied. In the absence of active thrombin (thrombin inactivated with DFP) polymerization of fibrin by calcium was accompanied by significant losses of AHF. In the presence of thrombin and calcium, 0.3 M glycine ethyl ester resulted in a significant reduction in the loss of AHF activity. * Present Address: Department of Pediatrics, Cincinnati Childrens Hospital, Cincinnati, Ohio.