Sometimes these Arab traders will actually settle for a year or two in the heart of some quiet community in the remote interior. They pretend perfect friendship; they molest no one; they barter honestly. They plant the seeds of their favorite vegetables and fruits--the Arab always carries seeds with him--as if they meant to stay for ever. Meantime they buy ivory, tusk after tusk, until great piles of it are buried beneath their huts and all their barter-goods are gone. Then one day, suddenly, the inevitable quarrel is picked. And then follows a wholesale massacre. Enough only are spared from the slaughter to carry the ivory to the coast; the grass-huts of the villages are set on fire; the Arabs strike camp; and the slave-march, worse than death, begins. This last act in the drama, the slave-march, is the aspect of slavery which, in the past, has chiefly aroused the passions and the sympathy of the outside world, but the greater evil is the demoralization and disintegration of communities by which it is necessarily preceded. It is essential to the traffic that the region drained by the slaver should be kept in perpetual political ferment; that, in order to prevent combination, chief should be pitted against chief; and that the moment any tribe threatened to assume a dominating strength it should either be broken up by the instigation of rebellion among its dependencies, or made a tool of at their expense. The inter-relation of tribe with tribe is so intricate that it is impossible to exaggerate the effect of disturbing the equilibrium at even a single centre. But, like a river, a slave-caravan has to be fed by innumerable tributaries all along its course--at first in order to gather a sufficient volume of human bodies for the start, and afterwards to replace the frightful loss by desertion, disablement, and death.