POISONS AND THEIR PREVENTION 199 



quite unable to afford any such service in the case 

 of animals inoculated with ordinary eel serum. 

 The full complement of protective power obtainable 

 from this treated eel serum is only able to slowly 

 assert itself, for it is necessary for a period 

 of as long as twenty-four hours to elapse after 

 its introduction to ensure the animal's system 

 being thoroughly impregnated with it and enable 

 it to withstand a lethal dose of viper venom. 



In this respect, what may be designated treated 

 or protective eel serum differs very markedly from 

 anti-venomous serum, which we have seen is 

 serum derived from animals trained up to with- 

 stand fatal does of serpent venom, for anti- 

 venomous serum acts immediately, and at once 

 confers immunity on an animal from the lethal 

 effects of such venom. 



The rapidity with which it acts is indeed one of 

 the most astonishing properties of this particular 

 anti-toxin. Thus if two cubic centimetres of anti- 

 venomous serum be inoculated into the marginal 

 vein of a rabbit's ear, it at once confers upon the 

 latter complete immunity from snake poison. 

 Immediately after the injection of the serum, 

 venom sufficient to destroy an ordinary rabbit 

 in a quarter of an hour may be injected with 

 impunity into the vein of the other ear. But not 

 only are the protective powers of this serum so 



