It is quite possible that a tribe does not keep slaves, though they would be very useful. The non-existence of slavery in such cases is due to external circumstances. It may be that the coercive power of the tribe is not sufficiently developed to admit of the keeping of slaves. It may also be that slavery does not exist, because it has not yet been invented: people may have always been accustomed to deal otherwise with their prisoners than by enslaving them, and so the idea of making slaves may never have entered their minds. The coercive power is strongest where men live in fixed habitations (though several tribes of pastoral nomads also keep slaves), and in large groups, and are accustomed to preserve food. The slave-trade has considerable influence. It increases the coercive power by rendering escape of slaves more difficult; and by making a tribe acquainted with the institution of slavery and providing it with an easy means of acquiring slaves it often overcomes the vis inertiae. The slave-trade may go far to account for the very frequent occurrence of slavery among savages who have long maintained relations with superior races, though due allowance must be made for the influence of the general intercourse with such races, especially in furthering the commercial development. Another external cause is the neighbourhood of [[426]]inferior races, the influence of which, as we have seen, clearly appears among pastoral tribes. It is easier for Hamitic and Semitic nations to keep Negroes in a state of subjection than people of their own race.
General recapitulation.
| Furthering the growth of slavery. | Hindering the growth of slavery. | |
| I. Internal causes. | ||
| A. General: | 1. Open resources and subsistence easy to acquire. | 1. Closed resources. |
| 2. Subsistence difficult to acquire. | ||
| B. Secondary, economic: | 1. A high position of women. | 1. Female labour serving as a substitute for slave labour. |
| 2. Commerce. | ||
| 3. Preserving of food. | 2. Subjection of tribes as such. | |
| C. Secondary, non-economic: | 1. Militarism (where slaves are employed in warfare). | 1. Militarism (especially where foreigners are adopted). |
| 2. Slaves kept as a luxury. | ||
| II. External causes: | 1. Fixed habitations. | |
| 2. Living in large groups. | ||
| 3. Preserving of food. | ||
| 4. The slave-trade. | ||
| 5. The neighbourhood of inferior races. | ||
Preserving of food and militarism occur twice, because they work in different directions.
We have arranged the separate causes within each group [[427]]in the order in which we have found them. If we had arranged them according to their relative importance, they would have been enumerated in another order. Thus among the external causes the slave-trade comes last, though its influence is greater than that of the other external causes[9].
§ 2. Outlines of a further investigation of the early history of slavery.
We have viewed slavery as an industrial system, and inquired under what economic and social conditions this system can exist. This investigation we believe has led to valuable conclusions. But slavery (even if we confine ourselves to slavery among savages) may be viewed under many more aspects. We have not made any further study of the subject; but having collected many ethnographical materials, we have become acquainted with a great number of details which may afford subjects of further investigation. We shall give here an enumeration of various points connected with slavery, though we do not claim that it is in any way complete: it would probably appear on closer scrutiny that many additions could be made to it. We shall mention the various points in short sentences, often in the form of inquiries. [[428]]
I. The different ways in which people become slaves.
There are: