392 THE SNAKES OF SOUTH AFRICA. 



various parts cannot be chemically separated as efficiently as 

 we would wish. 



We have, however, abundant evidence of this fact by extensive 

 observations of the effects of the different venoms on animals. 

 In Australia a professional snake-catcher rendered himself 

 immune to the bite of a common highly venomous snake, and 

 in the presence of men of science allowed himself to be bitten 

 repeatedly. No poisonous symptoms supervened, although the 

 bite from this particular species of snake would, in most cases, 

 cause rapid death in any one not immunized. 



This man acting under the impression that in consequence 

 he was immune to the venom of other species of snakes, once 

 carelessly handled a Denisonia superha, but was bitten, and died 

 the following day. 



How TO BECOME ImMUNE. 



A man can, with patience, render himself immune to the 

 bites of venomous snakes. For instance, if he desires to be 

 immune from the venom of a Puff Adder and Cape Cobra, it 

 would be necessary for him to inject under his skin an exceedingly 

 small dose (the fraction of a drop) of the mixed venoms of these 

 two snakes, and after the lapse of a fortnight or longer, inject a 

 slightly larger quantity, and continue the process every two weeks 

 with increasingly large doses, until he is able to tolerate enough 

 venom at a dose as would kill half a dozen men. The operation 

 would, however, be very tedious and prolonged, and would have 

 to be repeated over again with the venom of other species of 

 venomous South African Snakes if he desired to be quite immune 

 to the venoms of them all. If, however, a man was immune 

 to the venom of the two typical representatives of the great 

 snake families, viz. the Cobra and Puff Adder (Colubrine and 

 Viperine), he would not be likely to die if bitten by any other 

 species of South African venomous snake. Such experiments 

 are fraught with danger, for if the individual be in the habit 

 of drinking alcohol, or if, through over-eating or indulgence in 

 a too free meat diet, his blood should be in an inflammatory and 

 impure condition, then gangrene would as likely as not set in 

 at the point of the injection, and if death did not occur, sloughing 

 of the flesh, more or less extensive, would supervene. 



