The Start 13 



Moreover, even between these two allied genera of pit- 

 vipers, the differences in the action of the poison are 

 sufficiently marked to be easily recognizable, and to ren- 

 der the most effective anti-venomous serum for each 

 slightly different from the other. However, they are 

 near enough alike to make this difference, in practice, 

 of comparatively small consequence. In practice the 

 same serum can be used to neutralize the effect of either, 

 and, as will be seen later on, the snake that is immune 

 to one kind of venom is also immune to the other. 



But the effect of the venom of the poisonous* colu- 

 brine snakes is totally different from, although to the 

 full as deadly as, the effect of the poison of the rattle- 

 snake or jararaca. The serum that is an antidote as 

 regards the pit-viper is wholly or well-nigh useless as 

 regards the colubrines. The animal that is immune to 

 the bite of one may not be immune to the bite of the 

 other. The bite of a cobra or other colubrine poisonous 

 snake is more painful in its immediate effects than is 

 the bite of one of the big vipers. The victim suffers 

 more. There is a greater effect on the nerve-centres, 

 but less swelling of the wound itself, and, whereas the 

 blood of the rattlesnake's victim coagulates, the blood 

 of the victim of an elapine snake — that is, of one of the 

 only poisonous American colubrines — becomes watery 

 and incapable of coagulation. 



Snakes are highly specialized in every way, including 

 their prey. Some live exclusively on- warm-blooded, ani- 

 mals, on mammals, or birds. Some live exclusively on 

 batrachians, others only on lizards, a few only on insects. 

 A very few species live exclusively on other snakes. 



