Note 2 — Chapter II · GEOGRAPHICAL DISTRIBUTION OF SLAVERY.

b. If this is not clearly proved, there is still one particular, that being mentioned makes the existence of slavery very probable, viz. the fact that people are bought and sold within the tribe, except of course women sold for wives. For other kinds of subjected persons, serfs, lower classes, and subjects of a despot, are not bought or sold, at least not within the tribe. Beyond the limits of the tribe a man may be sold without previously having been a slave. Thus some African despots sell their subjects to Arabian slave-traders; such a sale does not prove that slavery exists within the tribe. But when a man is sold within the tribe, either he was already a slave, or he becomes such, e.g. as a punishment; in both cases slavery is practised by the tribe2.