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, hemagglutina- 
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 hemagglutinative 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 hemolysis which 
certain venoms produce. If we assume the formation of hemolytic lecithid 
by the action of venom upon lecithin to be due to a ferment-like action of 
venom hemolysins, 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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