In‐Vitro Studies with Ancrod (‘Arvin’)

S ummary . The effect of ancrod on the fibrinolytic enzyme system in vitro and on artificial thrombi in the Chandler tube system has been studied. Ancrod has no direct lytic activity and does not influence the rate of lysis of artificial thrombi in the Chandler tube. Clots formed by the action of ancrod are more susceptible to the lytic action of urokinase compared to those formed by thrombin but are equally as susceptible to spontaneous lysis as comparable thrombin clots. The rapidity with which the fibrin formed in vivo by ancrod is removed must be attributed to some process other than the generalized activity of the plasminogen–plasmin system.