THE PHYSIOLOGY OF -POISOXING 193 



Halford,' Sir Joseph Fayrer,^ C. J. Martin,' Delezenne/ Phisalix/' 

 and lastly Noc/ have shown that the venoms of CohVBRiVM exert 

 a manifestly anticoagulant action upon citrate-, chloridate-, or oxalate- 

 plasmas, and also upon blood mixed with venom on issuing from 

 the vessels. 



On adding 1 milligramme of Cobra-, Bungarus-, Australian 

 Pseudechis-, or Ancistrodon-yenora to 1 c.c. of citrate-, oxalate-, 

 or chlorjdate-plasma, and supplementing the mixture, after varying 

 periods of contact, with a quantity of chloride of calcium (for the 

 citrate- or oxalate-plasmas), or distilled water (for the saline 

 plasma) sufficient to produce coagulation in a few minutes in the 

 control tubes without venom, we find that coagulation no longer 

 takes place after one hour in the tubes containing Cobra- or 

 Bungarus-venom, and after ten minutes in those that contain the 

 venom of A7icistrodo7i. 



In doses less than 1 milligramme for 1 c.c. of plasma, these 

 venoms by themselves never produce coagulation as do those of 

 Lachesis or Vipera russellii. They are thus sharply differentiated 

 in this respect. 



If fresh blood issuing from the arteries of an animal be received 

 in a vessel containing a sufficient quantity of CoLUBKiNE-venom 

 (that of the Cobra for example), and steps be immediately taken to 

 ensure the perfect mixture of the venom and the blood, we find that 

 the latter has entirely lost its coagulability, just as though it had 

 been mixed with peptone or extract of leeches' heads. 



Again, if a mixture be made in vitro of coagulant venoms, such 



' Medical Times and Gazette, vol. ii., 1873. 



= " The Thanatophidia of India." Churchill, London, 1872. 



^ " On the Physiological Action of the Venom of the Australian Black Snake," 

 Proceedings of the Boy al Society of New South Wales, July 3, 1895. 



' Archives biologiqucs, 1897 and 1898 ; Cowptes rendus de la Societe do Bio- 

 logic, October 28, 1899. 



■'■ Comptes rendus de la Societe de Biologie, October 28, 1899 ; November 4, 

 1899; July 26, 1902. 



" Annales de I'Institut Pasteui', June, 1904. 



13 



