230 VENOMOUS SNAKES AND THE PHENOMENA OF THEIR VENOMS 



units is sufficiently strong for therapeutic purposes. The antivenin prepared 

 by Calmette had power equahng 20.000 units. Since 1895 Calmette has been 

 sending out his antivenin to various laboratories in India, Cochin China, and 

 Australia for trial in cases of snake bite. The antivenin is in bottles contain- 

 ing 10 c.c. each. The warning is given not to use it after the lapse of one 

 year from date of preparation, as its antitoxic power gradually diminishes 

 with age. 



It may be stated that Calmette employed in his immunization of horses the 

 following venoms : Cobra di capello {Naja tripudians) , Trimeresurus {Lache- 

 sis), Naja haje, Cerastes, Crotalus, Bothrops (Lachesis lanceolatus) , Pseudechis, 

 Hoplocephalus {Nolechis), and different species of European vipers. The 

 proportions of these venoms varied, but the venom of Naja tripudians was 

 most used. 



Some cases of snake bite successfully treated with Calmette's antivenin are 

 recorded, the reports having been made by Hankin and Lepinay in Asia. 



In July, 1896, Calmette ^ read a paper concerning the treatment of animals 

 poisoned with snake venom, by the injection of antivenomous serum, before 

 the laboratories of the conjoint board of the Royal College of Physicians 

 and Surgeons of London. It was accompanied by a series of experiments 

 demonstrating the preventive and curative properties of his antivenin against 

 the fatal poisoning of rabbits with cobra venom. Among others he made a 

 suggestion as to the method for testing accurately and promptly the strength 

 of the antivenomous serum. A standard solution of type venom must be 

 placed at the diposal of the appointed experts. The toxic unit of this solution 

 will be based upon the quantity of venom necessary to kill a rabbit of 2 kilo- 

 grams in 20 minutes by intravenous injection in the marginal vein of the ear; 

 the above c[uantity corresponding on the average to 0.002 gm. of cobra venom, 

 weighed dried, and 0.004 gm. of crotalus venom. An antivenomous serum, 

 to be sufficiently active for therapeutic use, must be a preservative in a mini- 

 mal lethal dose of 2 c.c. on intravenous injection of the toxic unit of venom. 

 The preventive inoculation must be made 1 5 minutes only before the injection 

 of the venom. The testing of the serum is thus effected in less than 30 

 minutes. 



Calmette and Delarde ^ state that immunity against venom can be produced 

 in cold-blooded animals by repeated injections of subminimal lethal doses, 

 but it may not necessarily be followed by the appearance in the blood of the 

 antivenomous principle in these animals, for example, in the frog. 



Calmette ^ published the details of his demonstrations of experimental 

 serum therapy of animals poisoned with venom, as shown in London, before 

 the Royal College of Physicians and Surgeons. He injected 6 rabbits (weight 

 1.450 to 1.770 grams) with 3 c.c. of antivenin intravenously. After 5 hours a 



1 Calmette. The treatment of animals poisoned with venom by the injection of antivenomous senim. 



Lancet, 1896, II, 449. 

 * Calmette and Delarde. Sur les toxines non-microbiennes et le mecanisme de I'immunite par les 



serums antitoxiques. Ann. Inst. Pasteur, 1896, X, 675. 

 3 Calmette. Sur le venin des serpents. Ibid., 1897, XI, 214. 



