Yet, as we have already said, those parts of the world where we have found most of our positive cases are exactly those where the slave-trade has been carried on by civilized and semi-civilized peoples. Going on to account for this fact, we may remark first that it need not have been the slave-trade only that furthered the growth of slavery. The general intercourse with superior races may go far to account for the rise of slavery, irrespectively of the slave-trade. We have seen that commercial tribes are more likely to keep slaves than others; and a savage tribe can engage in commerce with superior peoples, who buy large quantities of native produce and introduce foreign manufactures, to a far greater extent than with neighbouring savages who have not much to exchange, as their own and their neighbours’ mode of life and industrial development are nearly the same. A remarkable instance of the influence of commercial intercourse with Europeans on the slave system of a savage race is afforded by Polack’s description of the Maori. Formerly, he says, “for a chief to enter his new abode [in the world of spirits], without being ushered by a number of slaves and wives [who were sacrificed], was accounted the greatest indecorum that could possibly exist, but from the scarcity of slaves during late years [Polack wrote in 1840], or rather from the profits accruing from their employment in rearing pigs, and planting provisions, cutting timber, and cleaning flax for their numerous European visitors (their services being at a premium), these butcheries … have ceased”[334]. Something similar to this may often have taken place.
Probably, however, the slave-trade has also had considerable influence. The mere fact that foreigners purchase or capture slaves from savage tribes cannot, of course, account [[413]]for the existence of slavery among these savages; it may even result in the disappearance of slavery among them, if they find it more profitable to sell their slaves than retain them. But the slave-trade will often augment the opportunities of acquiring slaves. Slave-traders generally trade in other articles besides slaves; therefore they will often exchange some of the slaves they may have procured for something else. If some slaves are too weak to perform the journey to the coast, it is more profitable to sell them in the interior than to leave them behind. Moreover, the slave-traders often induce savages to make raids upon their neighbours and sell the captives they may secure; and if a savage chief has once learned in this way to kidnap slaves, he will perhaps continue to do so though there be not always a ready sale for them. In a word, the procuring of slaves becomes much easier.
Now we must bear in mind that an institution does not always exist in all countries where it would be economically useful. Not only is an institution which would further the public welfare often wanting, because the immediate interests of individuals are not concerned, but the individuals are not always aware even of their own immediate interests. Such may also be the case with slavery. It may be that, if slavery were introduced into some savage tribe, the tribe, or at least some members of the tribe, would profit by it, and that yet no slaves are made because there are not sufficiently strong motives for doing so, or because there are stronger motives working in the opposite direction. Tribes which have never kept slaves and are unacquainted with slave-keeping tribes, do not know the use of slavery; therefore they have to come to it gradually. Taking for granted that the first source of slavery, as seems very likely, was captivity in war, and that the captives, at first adopted, were afterwards differentiated from the main body of citizens, we can understand why slavery does not exist in all countries where the keeping of slaves would be profitable. It may be that it is the custom to eat the prisoners, or to sacrifice them, or to restore them when peace is concluded. It may also be that the adopted prisoners have from times immemorial been regarded as the equals of the tribesmen. In all these cases the new motive, [[414]]the want of slaves, must be strong if it is to break through the established custom. The vis inertiae plays a great part in the history of mankind.
Returning to the slave-trade, we may remark that this entirely overturns the existing state of things. It enables the tribe to procure slaves who are not captives, and regarding whom therefore no custom has been established. Moreover, the tribe becomes acquainted with the institution of slavery, which it had not seen practised before. Now there is no longer any reason why the members of such a tribe should not purchase the slaves offered to them and set them to work. An external cause has sufficed to disturb the former equilibrium.
We have remarked before that the slave-trade facilitates the keeping of slaves, because purchased slaves are less likely to escape than captives[335]. Here too we have to deal with the vis inertiae rather than with an impossibility in the strict sense of keeping slaves. It will not, probably, often be the case that agricultural savages would be quite unable to retain their slaves, if they were really very anxious to keep them; but it may often occur that they are not yet fully aware of the use of slaves, and therefore do not want to take the pains of supervising them, though, if slavery were thoroughly established, it would prove very profitable; in such case the objective want exists, but the subjective want is not yet felt. In this case, too, the slave-trade, by rendering escape of the slaves more difficult, will tend to establish the custom of keeping slaves.
Our conclusion is that slavery existed among some savages who had never had any intercourse with superior races, but that this intercourse, especially where the slave-trade was carried on, has often greatly furthered the growth of slavery.
In our chapter on pastoral tribes we have remarked that a tribe living in the vicinity of inferior races is more likely to keep slaves than one surrounded by tribes of the same or a higher level of culture. Enslavement of lower races also frequently [[415]]occurs among agriculturists; but the agriculturists of the higher races (e.g. Malays in the restricted sense, inhabitants of North Africa, etc.) are to be called barbarians rather than savages and have therefore been excluded from the survey of slavery given in our first Part.
Briefly recapitulating the conclusions we have arrived at with regard to agricultural tribes, we have to remark that the general character of their economic and social life is favourable to the existence of slavery: subsistence is easy to procure, and independent of capital, except where cattle are kept.