i;8 BACTERIA IN DAILY LIFE 



mammals to which Calmette administered this 

 cobra venom, such as monkeys, dogs, rabbits, 

 guinea-pigs, rats, succumbed more or less quickly, 

 according to the size of the dose. 



Small birds and pigeons die very rapidly, but 

 the domestic fowl is more fortunate, being some- 

 what less susceptible. Frogs also fall a prey to the 

 venom, but they are far more refractory than 

 rabbits, for it takes thirty hours to kill a frog with 

 a dose of venom which would infallibly destroy 

 a rabbit in ten minutes. Toads, curiously, do not 

 enjoy to the same extent this power of resisting 

 its toxic action, for they die more quickly than 

 frogs, whilst it makes short work of lizards and 

 chameleons. Fish form no exception to the rule, 

 and even invertebrates, such as leeches, are killed 

 by minute traces of venom. 



Whilst Calmette has found that the venom 

 of different kinds of reptiles exhibits marked 

 differences in its toxic character, he has also 

 discovered that the venom secreted by one and 

 the same serpent varies considerably, according 

 to the length of time the animal has fasted. He 

 describes how he kept a naja haje (Cleopatra's asp) 

 in his laboratory, which during the whole eight 

 months that it lived never took any food whatever, 

 although it was offered the most diverse dainties. 

 On its arrival it was made to bite on a watch-glass, 



