By various travellers and explorers, the fact has been observed that certain symbols representing force in their marriage ceremonies are in use among nearly if not all extant tribes which have reached a certain stage of growth. To such an extent, in an earlier age, has the forcible carrying-off of women prevailed, that among most of these tribes a valid marriage may not be consummated without the appearance of force in the nuptial ceremonies. In reference to these symbols, we have the following passage from Mr. McLennan: Meantime, we observe that, whenever we discover symbolical forms, we are justified in inferring that in the past life of the people employing them, there were corresponding realities; and if, among the primitive races which we examine, we find such realities as might naturally pass into such forms on an advance taking place in civility, then we may safely conclude (keeping within the conditions of a sound inference) that what these now are, those employing the symbols once were.[113] [113] _Studies in Ancient History_, p. 5. Among primitive tribes, the area controlled by each was small, therefore vigilance in maintaining their possessions was one of their chief duties, and hostility to surrounding tribes a natural condition. Subsequently, however, when friendly relations began to be established with hitherto hostile tribes, they are found entering into negotiations to furnish each other with wives. It was at this time that marriage by sale or contract was instituted, an arrangement by which the elder men in the tribe could be accommodated with foreign wives, at the same time that their own daughters and sisters became to them a source of revenue. In Uganda many men obtain wives by exchanging daughters and sisters with each other. Of this practice C. Staniland Wake says: This is not an unusual mode of proceeding in different parts of the world. The perpetuation of the monopoly of women enjoyed to a great extent by the older men of the tribe among the Australians is, according to Mr. Howitt, encouraged by those having sisters or daughters to exchange with each other for wives.[114] [114] _Marriage and Kinship_, p. 207. Not unfrequently actual capture is practised side by side with fiction—violent seizure being in active operation among the same tribes at the same time with the symbol, the frequency of actual violence depending partly on the extent to which hostility prevails between the tribes, and partly on the degree of “uniformity established by usage in the prices paid for wives.” Among certain tribes, when a dispute arises concerning the price to be paid for a bride, if the man is able to seize the woman and carry her off to his tent, the law recognizes her as his wife and nothing is left for the relations to do in the matter but to accept his terms as to the price.