CHAPTER XIX. 

 FERMENTS IN SNAKE VENOM. 



Apart from the cytolysins, of which detailed accounts have already been 

 given elsewhere, snake venom betrays by its actions the presence of four 

 distinct classes of ferment-like substances. These are the fibrin ferment, 

 proteolytic, diastatic, and lipolytic enzymes in the biochemical sense. The 

 amounts of these bodies in different kinds of snake venom are variable, one 

 predominating the other according to the nature of the venom; nor are the 

 amounts of these four constituents the same in a given kind of venom. 



That venom contains powerful fibrin ferments in the classical sense, and 

 that they form the most important part of the toxicity of certain viperine, 

 crotaline, and colubrine snake venoms, has already been fully related and 

 will not be repeated here. 



Just how much the other three ferments participate in the toxic effects of 

 snake venom is, however, open to further investigation. It appears to be 

 fairly certain that the neurotoxic, hemolytic, haemorrhagic, haemagglutina- 

 tive, as well as other dissolving effects on various groups of cells — liver, 

 kidney, testis, ova, spermatozoa, leucocytes — are not due to the action of 

 the proteolytic ferment considered under this heading. 



The lipolytic ferments may appear in some respect to have something to 

 do with the hemolytic and hsemagglutinative actions of venom, but judging 

 from their comparatively feeble power in splitting lecithin or neutral fats they 

 can not be the same principles responsible for the powerful haemolysis which 

 certain venoms produce. If we assume the formation of hsemolytic lecithid 

 by the action of venom upon lecithin to be due to a ferment-like action of 

 venom haemolysins, this is different from all other known ferments in their 

 stabilty to temperature and reactions. Unfortunately we are not yet in 

 possession of accurate data concerning the thermal and chemical stabilities 

 of venom lipases described by Neuberg and Rosenberg, and can not make 

 any definite statement as to the relation between these two sets of principles. 



The proteolytic action and anticoagulating property of venom are declared 

 to be due to the same principle by Calmette and Noc, while the softening 

 effects of venom upon muscle are ascribed by Flexner and Noguchi to the 

 similar enzyme of venom. Venom produces a marked degeneration of 

 various bacteria, as first described by Flexner and Noguchi and extended 

 by Noc, but we may not be justified in attributing this action solely to the 

 proteolytic action of venom. 



Before assigning to the three ferments here considered their proper posi- 

 tions among factors constituting general and separate toxicities of venom, 



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