362 THE SNAKES OF SOUTH AFRICA. 



a temperature of 70° to 80° C, snake venom throws down a 

 white flocculent precipitate. After the removal of this sediment 

 the solution is found in the case of Cobra venom to be quite 

 or almost as deadly as before boiling. Several hours' boiling, 

 however, entirely destroys the poisonous properties of Cobra 

 venom. When heated beyond 100° C, the toxic power of all 

 venoms is destroyed. 



It will thus be seen how very sensitive the venoms of Adders 

 are to heat when in solution, and how strongly Cobra venom, 

 under similar conditions, resists heat. 



Venom, in a dry condition, may be heated to 100" C. or a 

 little over without any alteration in its poisonous properties. 



If a blood vessel be punctured and the venom enters the 

 circulation direct, the effect is practically instantaneous, and 

 death occurs within a few moments. I found when the venoms 

 of the Boomslang and the Cape Cobra were injected direct into 

 the veins of animals, they were stricken with death as swiftly as 

 if shot through the brain. In one instance death occurred while 

 the dose was being injected. 



However, in cases of snake bite, the venom is usually deposited 

 in the muscular tissues and is absorbed by the small capillary 

 blood vessels and lymphatics adjacent to the bitten part, and 

 finds its way into the general circulation at a much slower rate.* 



The symptoms of snake bite vary according to the quantity 

 of venom absorbed, and its nature. 



Dr. Calmcttc states that the venom of the Lachesis genus of 

 snakes, which inhabit Asia and America, when swallowed sets up 

 acute inflammation of the gastric mucus membrane, and the 

 animals speedily succumb to attacks of gastro-intestinal haemor- 

 rhage. For several years, at intervals, I have fed animals by 

 administering as much as fifty times a fatal dose of venom daily 

 in their food for several days, without any apparent bad effect. 

 I have fed rats, fowls, cats, dogs, jackals, mungoosesand monkeys 

 on the venoms of South African snakes without any symptoms 

 of poisoning ensuing. The Ptyalin of saliva and the gastric and 

 pancreatic juices destroy the poisonous properties of snake 

 venom. 



It is a common practice of the Kafirs and Hottentots to 



* The volatile acid in fresh snake venom causes smarting in the wound 

 and hastens the absorption of the poison. Dry venom is neutral and is 

 absorbed more slowly when dissolved and injected. 



