This leads to the same conclusion we had already arrived at, that slavery is more likely to exist among agriculturists of the higher stages than among hunting agriculturists[316]. We do not think that anything more need be said on this subject.
In our chapter on pastoral tribes we have found that subjection of tribes as such sometimes serves as a substitute for slavery, making slavery proper superfluous. The same proved to be the case among agriculturists who depend on cattle for a large portion of their subsistence. Something analogous to this is the levying of tributes on conquered districts that so often occurs in Oceania, as we have found in § 8. Outside Oceania we have found only one instance among agriculturists who do not depend on cattle, and even this is a doubtful one. Morgan states that among the Iroquois the council “regulated the affairs of subjugated tribes”[317]; but he does not enter into more details, so we cannot exactly know what he means.
It is easy to understand, why subjection of tribes so seldom occurs among agriculturists. Hunting agriculturists, like true [[407]]hunters, generally live in small groups and therefore cannot keep other tribes in a state of subjection. And among agricultural tribes of the higher stages men as well as women are continually engaged in agricultural labour; they are attached to the spot on which they live and, unlike nomadic cattle-keepers[318], cannot easily control a neighbouring tribe. The vanquished tribe, by retreating a little, can place itself out of reach of the conquering tribe. Only where, as on the small Polynesian islands, escape is not practicable, can a vanquished district be kept in a state of subjection. The Iroquois were an exceptional case. They were hunting agriculturists in this sense, that agricultural labour was performed by the women only; but at the same time they had a strong military organization: the five nations formed a powerful union.
In the higher stages of culture the growth of militarism enables strong agricultural peoples to subject their weaker neighbours; and the growth of population prevents the latter from receding. But among agricultural savages subjugation of tribes is rarely found.
§ 18. External causes, especially the slave-trade. Recapitulation.
In the second and third chapters we have spoken of external causes. We have seen that for slavery to exist it is not sufficient that there should be some use for slave labour; it must also be possible to keep slaves; the freemen of the tribe must have a coercive power strong enough to keep the slaves subjected and prevent them from escaping. It has been shown that this coercive power is most strongly developed, where men have fixed habitations, live in large groups, and preserve food; and further, that the slave-trade greatly facilitates the keeping of slaves.
As for the first three points, it is easy to see that agricultural tribes of the higher stages are more settled, live in larger groups, and are more likely to preserve food than hunting [[408]]agriculturists[319], so here again we find a reason why slavery is so much more frequent among the former than among the latter.