SPECIFICITY AND THERAPEUTIC VALUES OF ANTIVENINS 243 



tension becomes very high, but the subsequent administration, also intra- 

 peritoneally, of an adequate amount of antivenin stops further distension and 

 accelerates resorption of the sanguine exudate very promptly. The quantity 

 of antivenin had to be increased the more the injection was delayed. 



The comparatively favorable results of experimental antivenin therapy 

 against the crotalus and moccasin venoms are no doubt to be ascribed to the 

 differences in the chief toxic principles of these American snake venoms and 

 of the Indian cobra venoms. At least the absorption of the haemorrhagins, 

 the chief toxins of the former, is much slower than the neurotoxins of the 

 latter; hence there is more chance for the antivenin to act directly and in 

 higher concentration. 



From these observations it would appear that antivehins, at least crotaline 

 antivenins, possess excellent neutralizing quality. 



The second factor which affects the therapeutic value of antivenins is the 

 conditions with which we have to deal in the practical cases of snake bite. 

 This is an unknown factor, namely, the quantity of venom injected into the 

 victim during the bite. It may happen that the snake injects the maximal 

 quantity of its venom, or it may inject only a small quantity. It is the first 

 hypothetical case that we ought to expect in practice. 



I have given the maximal quantities of venom per single bite for various 

 kinds of venomous snakes in a separate topic and shall avoid repetition here, 

 and take up only three representatives of subfamilies, Elapinse, Crotalinac, 

 and Viperinae, for the discussion (table 26). 



TABLE 26. 



Naja tripudians (cobra) yields about 0.2 to 0.35 gm. (dried). 



Crotalus adamanteus (rattlesnake) yields about 0.2 to 0.3 gm. (dried). 



Daboia russellii (chain viper) yields about 0.15 to 0.25 gm. (dried). 



Now the question arises as to the quantity of antivenins necessary to neu- 

 tralize the above doses when mixed directly in vitro. Of course the quantity 

 of antivenins depends upon the antitoxic units contained in them. 



According to Martin and Lamb l the cobra antivenin, prepared at the 

 Pasteur Institute in India, requires i c.c. to neutralize o.ooi gm. of dried 

 cobra venom, while Calmette's antivenin takes 2 c.c. for the same amount of 

 venom. 



Of preparations of crotalus antivenins prepared by Flexner and Noguchi, 

 0.5 c.c. neutralized o.ooi gm. of dried crotalus venom. 



Of the daboia antivenin, prepared by Lamb, i c.c. is required to neutralize 

 o.ooi gm. of the dried venom. 



From these figures we can immediately calculate the amount of each anti- 

 venin necessary to neutralize in vitro the maximal quantities of venoms liable 

 to be injected by the respective snakes into their victims. 



But here comes another consideration, namely, the maximal amount of 

 each venom which a man can resist. Calculated from the experiments made 

 upon monkeys the minimal lethal doses for cobra venom are placed by Lamb 



1 C. J. Martin and Lamb. Snake bite. Allbutt System of Medicine, 1907, II, London. 



