Amongst a few hundred people who are never out of touch with each other, the forms of natal association hold their own against any that local association is likely to suggest in their place.

According to natal grouping, therefore, in the broad sense that includes sex and age no less than kinship, the members of the tribe camp, fight, perform magical ceremonies, play games, are initiated, are married, and are buried.

But let the tribe increase in numbers, and spread through a considerable area, over the face of which communications are difficult and proportionately rare.
Instantly the local group tends to become all in all.

Authority and initiative must always rest with the men on the spot; and the old natal combinations, weakened by inevitable absenteeism, at last cease to represent the true framework of the social order.

They tend to linger on, of course, in the shape of subordinate institutions.