But their knowledge is probably very superficial as compared with that of a bushman in the Kalahari Desert of South Africa. Every man, woman, and child in such a tribe knows thoroughly every plant that grows in the neighbourhood. His diet is a varied one, for it includes maggots, fish, frogs, snakes, white ants, and other horrible ingredients, but he lives mainly on roots, bulbs, and herbs of sorts. In times of famine he has had to obtain the most intimate knowledge possible of many plants, that namely which is obtained by eating them, and he has most carefully observed the poisonous kinds. These latter have given him, too, a very powerful weapon, for it is the poisoned arrows which give him the chance of killing game, otherwise utterly beyond his reach. He is on the fair road to becoming a hunter and tribesman, instead of being only a member of a morose, outcast family, always wandering and always hungry. Probably poisons were first used in fishing. Many vegetable drugs, when thrown into pools and lakes, have the property of stupefying or killing the fish. A great many of these fish poisons are known, and it is quite easy to use them. Amongst the Dyaks of Borneo, screens of basketwork are placed along a stream to prevent the fish escaping. Then the Dyaks collect along either bank in their canoes. Everybody has a supply of the root of the tubai (_Menispermum sp._), which they hammer with stones in the water inside the canoe, so as to extract the poison. At a given signal the poisonous stuff is baled into the river, and very soon afterwards a scene of wild excitement begins, for the fish are speared or captured with handnets as they rise, stupefied, to the surface. The women scoop up the small fry in their nets.[106] [106] Ling Roth, _Journ. Anthrop. Inst._, vol. 22, London, 1892; and Mason, _l.c._ Even at the Sea of Galilee, Tristram mentions that Arabs sometimes obtain their fish by poisoned bread-crumbs. In the South Sea Islands, at Tahiti, a poison is obtained from the nuts of a kind of Betonica, and is used to catch the fish among the reefs near shore.[3] In West Africa several fish poisons are in use (e.g. seeds of _Tephrosia Vogelii_), and probably the same methods are used almost everywhere. They are by no means extinct even at home, for the occasional poacher sometimes uses fish poisons. 2 Tristram, _Land of Israel_; Mason, _Origin of Inventions_, p. 298.