THEIR NATURE AND EPPBOTS. 123 



experiments, and had been heated for an hour to 107° C. 

 •(225° F.) was again exposed for another hour to the 

 same heat. One cubic centimetre of it was then injected 

 into a fowl ; but the bird, though kept for a long time 

 under observation, never had any symptom of poisoning 

 at all. 



Here, then, after two hours' exposure in solution to a 

 very high temperature, the poison was at last destroyed. 

 But this destruction of the poisonous agent was gradual, 

 ■the solution becoming weaker as the application of 

 heat was continued. 



There are, however, some other facts in connection 

 with the effect of heat on cobra-poison that must be 

 mentioned. 



Experiment V. 



A solution of dried cobra-poison was made, containing 

 one centigramme (154 grain) of poison in twenty cubic 

 ■centimetres of water. One cubic centimetre of the 

 solution, containing "5 milligramme ('007 grain) of 

 poison, killed a fowl in forty-two minutes ; but this 

 ■solution, after being heated for half an hour to 106° C. 

 (^22°'8 F.) was found to be completely harmless. 



In this experiment a dilute solution of the poison 

 -was destroyed with comparative ease, whereas the solu- 

 tion used in the previous experiments, of 100 times the 

 strength, resisted prolonged heat. 



But it can be proved that even the heat of 100° C. has 

 ■a distinct effect in diminishing the strength of a solution 



