12 THROUGH THE BRAZILIAN WILDERNESS 



— to use a term which is vague, but which is as exact as 

 our present-day knowledge permits — that have developed 

 in so many different famiHes of snakes these poisoned fangs 

 have worked in two or three totally different fashions. 

 UnHke the vipers, the colubrine poisonous snakes have 

 small fangs, and their poison, though on the whole even 

 more deadly, has entirely different effects, and owes its 

 deadliness to entirely different qualities. Even within the 

 same family there are wide differences. In the jararaca an 

 extraordinary quantity of yellow venom is spurted from 

 the long poison-fangs. This poison is secreted in large 

 glands which, among vipers, give the head its peculiar ace- 

 of-spades shape. The rattlesnake yields a much smaller 

 quantity of white venom, but, quantity for quantity, this 

 white venom is more deadly. It is the great quantity of 

 venom injected by the long fangs of the jararaca, the bush- 

 master, and their fellows that renders their bite so generally 

 fatal. 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 render 

 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 colubrine 

 snakes is totally different from, although to the full as 

 deadly as, the effect of the poison of the rattlesnake or 

 jararaca. The serum that is an antidote as regards the 



