156 PHYT0T0XIK8 AND ZOOTOXINS 



the blood, which they found followed experimental venom poisoning. 

 This has been ascribed by Flexner and Noguchi to saturation of serum 

 complement by the numerous amboceptors of the venoms, so that no 

 complement is left for the serum to use against the bacteria. In 

 senim whose complements do not combine with the venom amboceptors 

 (e. g., Necturus) the normal bactericidal powers are not in the least 

 impaired by the addition of venom. Morgenroth and Kaya ascribe 

 the loss of complement to a destruction by some agent in the venom. 



Snake Serum. — The serum of serpents is also toxic for other ani- 

 mals,*®'' even when tlie serpent is not a venomous one ; e. g., the harm- 

 less pine snake (Pityophis catenifcris). The toxicity of snake serum 

 seems to depend chiefly upon its hemotoxic effects (hemagglutination 

 and hemolysis), the toxic substances resembling amboceptors and sim- 

 ilar to, but not altogether id'entical with, the amboceptor of the ven- 

 oms. Crotalus tissues also produce poisoning in proportion to the 

 blood they contain, but are without toxic effects of their own (Flex- 

 ner and Noguchi). 



Antivenin. — Snake venom has the essential propertj^ of all true 

 toxins of immunizing, with the appearance of an antitoxin in the 

 blood. The first successful immunizations seem to have been made 

 by Sewall,*" but the practical production of antitoxic serum was first 

 accomplished by Calmette *^ and by Fraser.*^ At first it was be- 

 lieved that cobra antivenin neutralizes the neurotoxins and hemoly- 

 sins of venoms of any origin, and also of snake serums, and, therefore, 

 should be quite effective against cobra and similar venoms which pro- 

 duce chiefly neurotoxic and hemolytic changes. This implies that these 

 toxic substances are of identical nature in all snakes, no matter how 

 dissimilar the snakes may be, but various investigators, especially 

 Lamb, have found sufficient specificity exhibited by different venoms 

 and antivenoms to indicate the necessity of employing the specific 

 antiserum in each case of snake bite. A special antitoxin against rat- 

 tlesnake venom and its hemorrhagic toxin has been successfully pre- 

 pared by Noguchi.-'^*' This crotalus antivenin also neutralizes hemo- 

 lysins of various venoms, and also of snake serums. 



Presumably antivenin neutralizes venoms in exactl.y the same way 

 that antitoxin neutralizes toxins; i. e., cell receptors are tlirown off 

 from the injured cells during immunization, which combine with 

 venom amboceptors in the blood, and thus prevent their combining 

 vnth the cells. Antivenin also prevents the inhibiting action of venom 

 on bactericidal serum, indicating that it prevents the venom ambo- 

 ceptors from binding the serum comj^h'iuciit. Tlie reaction of venom 



40a Questioned hv Wolkcr and :\rarsliall, Jour, riiannacol.. 1015 (0), 503. 

 47 Jour, of Pliysiol., ]SS7 (S). 203. 



48i\nn. d. I'Insl. rastcur, 18!)4 (6), 275; also sul)so(iiu'n( arfu-les in 1897 (11), 

 214; 1808 (12), .343. 



49 British Mod. Jour., 1805 (i). 1300. 



coUniv of I'.Miii. Med. I'.iill.. 1004 (17), 154; Joiir. Exper. Mod., 1006 (8), G14. 



