CHAPTER VIII. 



EFFECTS OF VARIOUS PHYSICAL AND CHEMICAL AGENTS 

 UPON SNAKE VENOM. 



This includes the effects of various physical and chemical agents on venom 

 en masse as well as on certain active constituents of venom obtained by 

 chemical processes. As the constituents of different venoms differ both in 

 quantity and quality, the effects of various agents upon them differ accord- 

 ingly. 



EFFECTS OF PHYSICAL AGENTS. 



Effect of desiccation: When allowed to dry at ordinary temperature, all 

 venoms do not suffer a loss in their toxicity. In some viperine or crotaline 

 venoms a slight reduction in their local activity has been observed after 

 desiccation, but never to a great extent. 



Effect of preservation : The active principles of snake venom are very 

 stable when kept in a dry state or in a mixture with equal quantity of gly- 

 cerin. So far as records go, dried crotalus venom after 23 years was just as 

 active as when it was freshly collected (Mitchell), and dried cobra venom 

 preserved for 15 years (Christison) or 1 6 years (Vollmer) did not show any 

 sign of deterioration of its original strength. On the other hand, when in 

 saline or watery solution, the venom gradually loses its activity. This fact is 

 especially marked with cobra venom, and at body temperature. 



Effect of moist heat: The venom of Elapinae (Naja, Elaps, Bungarus, 

 Hoplocephalus, Pseudechis) can be exposed to the temperature of 100 C. for 

 a brief period, without reducing its activity to any marked degree. Fayrer 

 and Brunton mention that a 3O-minutes heating of cobra venom at 102 C. 

 destroys the latter. Wall states that 106 C. maintained for 30 minutes is 

 sufficient to destroy cobra venom. Kanthack saw cobra venom become 

 harmless after an hour's boiling at 100 C. Mitchell and Reichert found 

 that the prolonged boiling produced gradual coagulation of the venom- 

 peptone and rendered it inert. 



The venom of Hydrophiinae withstands even a brief boiling with im- 

 punity. 120 C. always suffices to cause total inactivation or destruction 

 of all venoms. 



The venoms of Viperinse and Crotalinae are much more sensitive to the 

 destructive action of heating. The temperature which produces coagulation 

 of the proteins of these venoms destroys the greater part of their poisonous 

 activity. The temperature of 72 to 75 C. removes most of the toxicity, 

 while almost complete inactivation is brought about at 80 to 85 C. But 



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