1 84 BACTERIA IN DAILY LIFE 



grade ; whilst an exposure to only 80 Centigrade 

 for ten minutes is sufficient in the case of viper 

 venom, according to Messrs. Phisalix and Bertrand, 

 to profoundly modify its lethal action. A contin- 

 uous exposure for a fortnight to a temperature of 

 38 Centigrade does not affect cobra venom in the 

 least ; but if during that same time it has been 

 placed in the sunshine, it entirely loses all its lethal 

 properties. Thus, a pigeon was inoculated with 

 about thirty drops of venom which had been ex- 

 posed to the sun's rays for fourteen days, and it 

 survived ; whilst another pigeon was inoculated 

 with a little over six drops of similar venom which 

 had been kept during this time in the dark, and it 

 died in a quarter of an hour. 



All these elaborate researches as to the character 

 of serpent venom were essential to enable the next 

 step to be taken in the elaboration of the antidote. 

 Before this great achievement could be accom- 

 plished it was necessary to first succeed in arti- 

 ficially immunising animals against the effects of 

 this powerful toxin, so that the serum of such 

 animals could be applied for the protection and 

 cure of other animals from the effects of snake- 

 -bites. 



It may be readily conceived that the task of 

 artificially rendering animals immune from snake 

 poison was not an easy one, for the process 



