CHAPTER XXIV. 

 SPECIFICITY AND THERAPEUTIC VALUES OF ANTIVENINS. 



SPECIFICITY OF ANTIVENINS AS A WHOLE. 



Calmette at one time held that the neutralizing property of an antivenin 

 is not quite specific, and that a number of immune serums produced by cer- 

 tain plant toxalbumins or bacterial toxins can equally counteract the effects 

 of snake venom, but the experimental evidences brought out by many inves- 

 tigators now seem to contradict this view. The investigations of Stephens 

 and Myers seem conclusive on this point. They ^ first studied the effect of 

 Calmette's antivenin upon the haemolytic power of cobra venom and found 

 that haemolysis can be completely prevented by adding enough antivenin, 

 and that the relation holds good for a muUiple of doses. This antihaemo- 

 lytic property was found to be specific to the antivenin. They also studied 

 the relation between the antihsemolytic and the antitoxic powers of the anti- 

 venin and found that with only i minimal lethal dose the neutralization went 

 hand in hand for both principles, but with multiple doses a mixture haemo- 

 lytically neutral still proved fatal. 



In a subsequent paper ^ the same authors extended their study on the 

 specific protective action of antivenin, the anticlotting power of cobra venom 

 being used as a test-reaction. They arrived at the same conclusions as in 

 their previous experiments on haemolysis, namely, that the anticlotting power 

 of cobra venom can be neutrahzed by the antivenin and that this neutraliza- 

 tion is specific. They state that the neutrahzation of the anticlotting and that 

 of the toxic power of cobra venom run parallel as long as only one minimal 

 lethal dose is used, but this ratio does not hold good in multiple doses of 

 venom in regard to its lethal effects in vivo. 



SPECIFICITY OF ANTIVENINS DUE TO DIFFERENCES IN THE CHARACTER- 

 ISTIC TOXIC PRINCIPLES OF THE VENOM OF EACH SPECIES. 



The fatal effects of various kinds of snake venoms are by no means due 

 to one toxic principle, but are produced by different sets of toxins which vary 

 according to the kind of venom. Thus in the venoms of Naja, Bunganis, 

 and all of the Hydrophiinae death is produced through the neurotoxins present 

 in these venoms in dominating proportions. On the other hand, the venoms 

 of Viperinae, namely, those of Daboia or Echis, cause instantaneous death by 



» Stephens and Myers. Test-tube reactions between cobra poison and its antitoxin. Brit. Med. Jour., 

 1898, I, 620. • , J r • 



2 Stephens and Myers. The action of cobra poison on the blood, a contribution to the study of passive 

 immunity. Jour, of Path, and Bacter., 1898, V, 279. 



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