i8o BACTERIA IN DAILY LIFE 



absolutely no inconvenience, and the same results 

 were obtained with harmless snakes. On repeat- 

 ing these experiments, however, and using much 

 larger quantities of venom, Calmette has found 

 that they do ultimately succumb. That their 

 susceptibility in comparison with other animals 

 is very slight, may be gathered from the fact that 

 a lethal dose of venom for reptiles is roughly esti- 

 mated to amount to as much as three times the 

 quantity of venom normally present in their 

 respective poison glands. These animals, there- 

 fore, although very refractory, are not absolutely 

 immune from the action of venom-toxin. 



There are, however, other animals which enjoy 

 a relative although not absolute immunity to snake 

 poison, and amongst these may be mentioned 

 swine, hedgehogs, and the mongoose. Swine, it 

 is well known, will greedily devour reptiles, and in 

 some countries they are specially trained up and 

 employed for this purpose. Of particular interest, 

 however, are some experiments which were carried 

 out to test the traditional immunity towards this 

 toxin ascribed to the mongoose. These animals 

 are very .useful in sugar plantations, and are largely 

 employed to keep down the serpents and rats with 

 which they abound, for the carnivorous little mon- 

 goose is extremely partial to such prey. Attempts 

 have been made by sugar planters to introduce 



