V. Illness and Death

A tribe in Africa uses a certain species of dog for hunting; in the same region there is a fly whose venom is deadly to the dogs they sting. The savages living by the Sambesi River have found a remedy for these stings. They take the bitches in pup to an area where there is an abundance of tsetse flies and let them be bitten. The tribe knows how to arrange matters so that the bitches do not die before the pups arrive. The pups born in this way are immune to the tsetse fly's sting and can be used for hunting.