powell] SOCIOLOGY, OR THE SCIENCE OF INSTITUTIONS 7°3
especially wise, he might be promoted from time to time, until at last the captive might become a chief.
Captives taken from tribes that are hereditary enemies and between which there have grown historic feuds, and who are held to practice monster sins, such as cannibalism, are given a fixed status from their birth into the clan, which they cannot pass with- out promotion ; for all persons naturally born into the clan may call them younger and have authority over them. This is the primal form of slavery : but by good behavior the rules of such slavery may be greatly relaxed, and captives from hated enemies may ultimately become promoted kindred.
A person may not marry another of the same clan, but usually he must marry some one of the tribe not in his own clan. Before the marriage customs of the tribes of America were properly understood, a theory of endogamy and exogamy was developed by McLennan and others, which has played quite a role in theories of ethnology. There are a great number of languages spoken by the tribes of America ; so that the terms used to signify the clan and the tribe are multitudinous. The earlier writers on marriage customs in tribal society culled from the literature of travels a vast body of stories about taboos in marriage ; and it was finally concluded that certain tribes required their tribesmen to marry women who were foreigners and aliens. This was called exogamy. Then it was held that other tribes required or permitted their tribesmen to take wives within the tribe; and this was called endogamy. So an attempt was made to classify the tribes of mankind, not only in America, but elsewhere, into two groups, the exogamous and the endogamous.
Now we understand that in all tribal society there is an endogamous, or incest, group, which we call the clan in savagery, and the gens in barbarism ; while, at the same time, the clansmen usually marry within the tribe by regulations which vary greatly from people to people. It seems that the ties of marriage are used to bind different peoples together in one larger group which
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