ls us to admit this form as a necessary
step.

2. THE PUNALUAN FAMILY.

While the first step of organization consisted in excluding parents and
children from mutual sexual intercourse, the second was the erection of
a barrier between brother and sister. This progress was much more
important on account of the greater equality in the ages of the parties
concerned, but also far more difficult. It was accomplished gradually,
probably beginning with the exclusion of the natural sister (i. e., on
the mother's side) from sexual intercourse, first in single cases, then
becoming more and more the rule (in Hawaii exceptions were still noted
during the nineteenth century), and finally ending with the prohibition
of marriage even among collateral brothers and sisters, i. e., what we
now term brother's and sister's children, grandchildren, and
great-grandchildren. This progress offers, according to Morgan, an
excellent illustration how the principle of natural selection works.
Without question, the tribes limiting inbreeding by this progress
developed faster and more completely than those retaining the marriage
between brothers and sisters as a rule and law. And how powerfully the
influence of this progress was felt, is shown by the institution of the
gens, directly attributable to it and passing far beyond the goal. The
gens is the foundation of the social order of most, if not all,
barbarian nations, and in Greece and Rome we step immediately from it to
civilization.

Every primeval family necessarily had to divide after a few generations.
The originally communistic and collective household existing far into
the middle stage of barbarism, involved a certain maximum size of the
family, variable according to conditions, but still limited in a degree.
As soon as the conception of the impropriety of sexual intercourse
between children of the same mother arose, it naturally became effective
on such occasions as the division of old and the foundation of new
household communities (which, however, did not necessarily coincide with
the family group). One or more series of sisters became the center of
one group, their natural brothers that of another. In this or a similar
manner that form which Morgan styles the Punaluan family developed from
the consanguine family. According to Hawaiian custom, a number of
sisters, natural or more remote (i. e., cousins of the first, second and
more remote degrees) were the mutual wives of their mutua