178 PHYTOTOXINS AND ZOOTOXINS 



venom amboceptors (e. g., Nedurus) the normal bactericidal 

 powers are not in the least impaired by the addition of venom. 



Snake Serum. The serum of serpents is also toxic for 

 other animals, even when the serpent is not a venomous one ; 

 e. g.j the harmless pine snake (Pityophis cateniferis). The toxic- 

 ity of snake serum seems to depend chiefly upon its hemotoxic 

 effects (hemagglutination and hemolysis), the toxic substances 

 being in the nature of amboceptors and similar to, but not alto- 

 gether identical with, the amboceptor of the venoms. Crotalus 

 tissues also produce poisoning in proportion to the blood they 

 contain, but are without toxic effects of their own (Flexner 

 and Noguchi). 



Antivenin. Snake venom has the essential property 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, 1 but the practical production of antitoxic 

 serum was first accomplished by Calmette 2 and by Eraser. 3 

 This antivenin neutralizes the neurotoxins and hemolysins of 

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

 is quite effective against cobra and similar venoms which pro- 

 duce chiefly neurotoxic and hemolytic changes. This indicates 

 that these toxic substances are of identical nature in all snakes, 

 no matter how dissimilar the snakes may be. Cobra antivenin 

 does not, however, neutralize the hemorrhagin of rattlesnake 

 venom, for the venoms used by Calmette do not contain this 

 principle abundantly. A special antitoxin against rattlesnake 

 venom and its hemorrhagic toxin has been successfully prepared 

 by Noguchi. 4 This crotalus antivenin also neutralizes hemo- 

 lysins of all sorts of venoms, and also of snake serums. 



Presumably antivenin neutralizes venoms in exactly the same 

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

 thrown off from the injured cells during immunization, which 

 combine with venom amboceptors in the blood, and thus prevent 

 their combining with the cells. Antivenin also prevents the 

 inhibiting action of venom on bactericidal serum, indicating that 

 it prevents the venom amboceptors from binding the serum 

 complement. The reaction of venom and antivenin is certainly a 

 chemical one, being likened by Kyes 5 to that of strong acids 

 upon strong bases. 



1 Jour, of Physiol., 1887 (8), 203. 



2 Ann. d. F Inst. Pasteur. 1894 (6), 275 ; also subsequent articles in 1897 

 (11), 214; 1898 (12), 343. ' 



3 British Med. Jour., 1895 (i), 1309. 



4 Univ. of Penn. Med. Bull., 1904 (17), 154. 

 5 Berl. klin. Woch., 1904 (41), 494. 



