The inactivating effect of Bothrops jararaca and Waglerophis merremii snake plasma on the coagulant activity of various snake venoms.

Plasmas of the poisonous snake Bothrops jararaca and of the non-poisonous snake Waglerophis merremii were not clotted by various snake venoms. These plasmas also inactivated venom clotting activity on human plasma. This effect was absent in snake serum and in heated snake plasma. The active fraction was isolated by gel chromatography from B. jararaca plasma and corresponded to the fibrinogen-containing fractions. It is suggested that the inactivation by snake plasma of the venom coagulant activity might be due to a fibrinogen-bound complex or to fibrinogen itself.