TOXINS OF THE HIGHER PLANTS AND ANIMALS 121 



ZOOTOXINS 



The most important animal toxins (zootoxins) are those of the toad, 

 spider, snake, scorpion, and bee. The most striking characteristic of 

 these toxins is that an immunity against them can be established; in 

 this respect they resemble true toxins. All are quite complex in struc- 

 ture and properties, and all are more or less hemotoxic. 



Snake Venoms. 1 Medically, these are of particular interest. They 

 were first thoroughly investigated by S. Weir Mitchell (1860) and 

 Mitchell and Reichert (1883), and have aroused considerable attention 

 because of their similarity to bacterial toxins and the aid their study 

 has been in the elucidation of immunologic problems. 



Properties of Venom. In 1883 Mitchell and Reichert described two 

 poisonous proteins, constituents of venom, one of which seemed to be a 

 globulin and the other a proteose or "peptone." Faust 2 believes that 

 the poisons are not proteins, but glucosids free from nitrogen, and that 

 they belong to the saponin group of hemotoxic agents. It may be that 

 these glucosids are bound to proteins, and can be removed with the 

 globulin in fractional separation, or that they may come down, at least 

 in part, with the albumoses of the venom. 



Various enzymes have been found in venoms; e.g., proteases (Flex- 

 ner and Noguchi) and Upases (Noguchi); the latter probably have a 

 definite relation to many of the effects of venom intoxication, especially 

 hemolysis and fatty degeneration of the tissues. 



The poisons, as a rule, produce both local and severe general dis- 

 turbances, the rapidity of the onset of the symptoms and the prognosis 

 in a given case depending largely on the situation of the bite. Most of 

 these poisons exert their effect primarily upon the nervous and vascular 

 systems, besides exhibiting other toxic properties. 



Nature of Venoms. All snake venoms possess a hemolytic power, and 

 venom hemolysis is one of the most interesting of biologic phenomena. 

 Flexner and Noguchi 8 have distinguished and classified the various 

 elements as hemotoxins, hemagglutinins, neurotoxins, leukotoxins, and 

 endotheliotoxins (hemorrhagin). The endotheliolytic action of the 

 toxins is shown in the glomerular capillaries, where it causes hemorrhage 

 and hematuria (Pearce 4 ). 



1 See Faust: "Die tierischen Gifte," Braunschweig, 1906; Noguchi: Carnegie 

 Institution Publications, 1909, No. Ill; Calmette: "Les venins," etc., Paris, 

 Masson, 1907. 



2 Arch. exp. Path. u. Pharm., 1907, 56, 236; 1911, 64, 244. 



3 Jour. Exp. Med., 1903, 9, 257; Univ. of Penna. Med. Bull., 1902, 15, 345. 



4 Jour. Exp. Med., 1909, 11, 532. 



