422 THE SNAKES OF SOUTH AFRICA. 



Africa proved useless when I carefully tested them, some indeed 

 were actually poisonous. Many a human life has been lost 

 through the poisonous effects of alleged snake-bite antidotes. 



Usually a man who has recovered after, being bitten once or 

 twice by a venomous snake, imagines himself to be immune to 

 the poisons of snakes, but he is not so. Should he have been 

 seriously poisoned, his body will certainly be more resistant to 

 venom than a man who has never been bitten, but it must be 

 borne in mind that a snake is capable of injecting many times 

 a fatal dose of venom. Should a man have rendered himself 

 immune to, say, one ordinary fatal dose of snake poison, and a 

 snake injects two ordinary fatal doses into him, he will recover 

 for the reason that his blood serum is capable of at once 

 neutralizing half of the poison, and the resistance set up by the 

 natural defensive forces of the body will destroy about one-half 

 of the remainder, and so prevent a fatal issue. However, if two 

 and a half ordinary fatal doses of venom have been injected, his 

 body will not succeed in overpowering sufficient of the poison to 

 render recovery possible. 



Again, should a man have recovered after being three or 

 four times bitten by one of the Adder family of snakes, he will 

 only be slightly resistant to Cobra venom, for the reason that 

 the latter is a neurotoxin or nerve poison, while the former is 

 mainly a hcBmorrhagin or blood poison, and the small amount of 

 nerve poison it contains would not have been sufficient to have 

 rendered the man's body strongly resistant to Cobra venom. 

 On the other hand, should he have recovered even many times 

 from bites by Cobras, or from artificial injections of their venom, 

 he will be in no way immune to the blood-poisoning and 

 haemorrhage induced by the venoms of Adders, although he 

 would eventually recover unless he had received an unusually 

 large dose of poison, which, of course, would cause haemorrhage 

 under the skin and into various organs of too serious a nature 

 for the defences of the body to overcome. 



It must be remembered, however, that the neurotoxin or 

 nerve poison in snake venom is the portion which is the most 

 virulent, and if this element is neutralized in Adder venom, there 

 is far less likelihood of the victim dying. 



By injecting increasingly large doses of venom extending 

 over a long period, the body is able slowly to brmg about a 



