It was much more probable, Bomba thought, that the visit of the head-hunters to that district had been laid by the Araos at the door of Casson. It might have brought to a head all the superstitious feelings they themselves had entertained in regard to the old naturalist. Perhaps he was a Man of Evil, as the head-hunters declared. If so, he ought to be put out of the way. At any rate, if he were killed, perhaps the head-hunters would go back to the Giant Cataract and trouble the Araos no more.