and keeps the children for
slaves. Hence, the banana zone has been the great reservoir for
supplying slaves to other parts of the world. Hundreds of thousands of
slaves came from this zone to the West Indies, and to the slave states
of North and South America. In Dahomey and Ashanti war captives used
to be sold "en bloc" to white traders at so much per capita.

In the agricultural zones to the north and south nature is more
niggardly, though she yields enough, when coaxed by the hoe, to permit
of a large class of parasites. The labor of maintenance is more
onerous than in the banana zone. While the heat and humidity are not
so great the work is more grievous because of its greater quantity and
monotony. The motive to shift the work is, therefore, very strong and
the demand for slaves is very great. In fact, the ratio of slaves to
freemen is about three or four to one. As land is free and the
resources open, the only means of obtaining workers is by coercion.
The supply of slaves is kept up by kidnapping, by warfare upon weak
tribes, by the purchase of children from improvident parents, and by
forfeiture of freedom through crime.

In the cattle zones farther to the north and south, nature is still
less bountiful. The labor of maintenance requires a combination of
the pastoral art, agriculture and trade. A slave class could not
maintain itself and at the same time support a large master class. The
labor of a large proportion of the population is, in one way or
another, necessary to existence. The nature of the work, so far as it
is pastoral or trading, is not especially irksome, but rather
fascinating. Tending cattle is full of excitement, and is a kind of
substitute for hunting; while trading is an occupation which appeals
with wonderful force to all the races of Africa. The impulse to shift
labor in the cattle zones is, therefore, very slight, except in the
case of a few populations subsisting largely upon agriculture. The
ruling classes, therefore, instead of owning many personal slaves,
make a practice of subjugating the agricultural groups in such a way
as to constitute a kind of feudalism. As land is free the enslaved
groups can be made to serve the free class only by coercion.

Similar conditions among the natural races all over the world give
rise in the same way to the institution of slavery. Ellis thinks that
slavery probably originated under the regime of exogamy where the sons
born of captured women formed