For travel by land there were nothing but narrow, rough and tortuous foot-paths, with makeshift bridges across the smaller streams.

The rivers were highly advantageous both as avenues and as sources of food, for the negroes were expert at canoeing and fishing.
Intertribal wars were occasional, but a crude comity lessened their frequency.

Thus if a man of one village murdered one of another, the aggrieved village if too weak to procure direct redress might save its face by killing someone in a third village, whereupon the third must by intertribal convention make common cause with the second at once, or else coerce a fourth into the punitive alliance by applying the same sort of persuasion that it had just felt.

These later killings in the series were not regarded as murders but as diplomatic overtures.

The system was hard upon those who were sacrificed in its operation, but it kept a check upon outlawry.
A skin stretched over the section of a hollow tree, and usually so constructed as to have two tones, made an instrument of extraordinary use in communication as well as in music.