But the direst of all the reptiles bred in the sand is the dipsas or thirst-snake; it is of no great size, and resembles the viper; its bite is sharp, and the venom acts at once, inducing agonies to which there is no relief. The flesh is burnt up and mortified, the victims feel as if on fire, and yell like men at the stake. But the most overpowering of their torments is that indicated by the creature’s name. They have an intolerable thirst; and the remarkable thing is, the more they drink, the more they want to drink, the appetite growing with what it feeds on. You will never quench their thirst, though you give them all the water in Nile or Danube; water will be fuel, as much as if you tried to put out a fire with oil.