177 



The Nature of the Coagulant of the Venom of Echis carinatus, 



a Small Indian Viper. 

 By J. 0. Wakelin Baebatt, M.D., D.Sc. Lond. 



(Communicated by Prof. J. N. Langley, F.RS. Received July 22, 1913.) 

 (From the Liverpool Cancer Research Laboratory, the University, Liverpool.) 



CONTENTS. 



Page 



Introduction 177 



Action of thrombin and thrombokinase upon circulating blood plasma... 178 



Effect of heat upon thrombin and thrombokinase 184 



Action of viper venom upon circulating blood plasma 186 



Effect of heat upon viper venom 189 



Summary 190 



The effect of intravascular injection of the venom of the Australian 

 black snake (Notechis porphi/riacus) upon blood coagulation was studied by 

 G. J. Martin,* who, noticing the similarity of the resulting changes with those 

 described by Wooldridge,f after intravascular injection of " tissue fibrinogen," 

 inferred that in both cases the mechanism involved was the same, namely, 

 the introduction of nucleo-proteins into the blood stream, the liberation of 

 these substances after the injection of viper venom being presumably due 

 to the latter damaging the endothelial cells of the blood-vessels. 



Subsequently it was observed by LambJ that the addition of viper venom 

 to citrated or oxalated blood plasma also caused clotting. Martin § therefore 

 abandoned the explanation he had previously suggested and concluded that 

 the coagulant action of viper venom was due to fibrin ferment. 



The subject was later reinvestigated by J. Mellanby,|| who recognised that 



* C. J. Martin, "On some Effects upon the Blood produced by the Venom of the 

 Australian Black Snake," ' Journ. Physiol.,' 1893, vol. 15, p. 380 ; " On the Physiological 

 Action of the Venom of the Australian Black Snake," 'Roy. Soc. N.S.W. Proc.,' 1895 ; 

 " Subcutaneous and Intravenous Injection of the Venoms of the Australian Snakes," 

 'Roy. Soc. N.S.W. Proc.,' 1896. 



t L. C. Wooldridge, " On the Origin of the Fibrin Ferment," ' Roy. Soc. Proc.,' 1884, 

 vol. 36, p. 417. 



% G. Lamb, "On the Actions of Venoms of the Cobra {Naja tripudians) and of the 

 Daboia {Dabuia russellii) on the Red Blood Corpuscles and on the Blood Plasma," 

 « Scientific Memoirs by Officers of the Medical and Sanitary Department of the Govern- 

 ment of India,' 1903, New Series, No. 4. 



§ C. J. Martin, " Observations upon Fibrin Ferments in the Venoms of Snakes and the 

 Time Relations of their Action," 'Journ. Physiol.,' 1905, vol. 32, p. 207. 



|| J. Mellanby, "The Coagulation of the Blood, Part II," 'Journ. Physiol.,' 1909, 

 vol. 38, p. 441. 



