102 STORY OF THE REPTILES 



chameleons, where in one case there are as many as 

 three horns. In another there is a peculiar forked 

 prolongation of the snout. 



Among the snakes some vipers have horns — some- 

 times one on the tip of the snout, sometimes two — 

 one over each eye. Their use can scarcely be under- 



FiG. 53.— The horned toad. 



stood. It is said to be the rule that snakes do not 

 fight as rivals ; and it is fairly well known that the 

 bite of a poisonous snake is not harmless to his 

 brother, and often not injurious to other non-poisonous 

 kinds. Dr. S. Weir Mitchell states that he has re- 

 peatedly injected the poison of snakes into their own 

 bodies and seen no ill effects from it; and a corre- 

 spondent of the author (a scientific collector) states 

 that he has frequently boxed rattlesnakes and non- 

 poisonous sorts together and observed them bite one 

 another without ill effects. But more recently a Paris 

 experimenter claims that one snake is affected by the 

 venom of another in proportion as it is itself poison- 

 ous. This should cause innocent snakes to suffer. It 



