artificial association, into which the idea of natural kindred did not
enter. It is indeed possible that really artificial _gentes_, groups of
men of whom it might chance that none were natural kinsmen, were formed
in later times after the model of the original _gentes_. Still such
imitation would bear witness to the original conception of the _gens_.
It would be the doctrine of adoption turned the other way; instead of a
father adopting a son, a number of men would agree to adopt a common
father. The family then grew into the _gens_; the union of _gentes_
formed the state, the political community, which in its first form was
commonly a tribe. Then came the nation, formed of a union of tribes.
Kindred, real or artificial, is the one basis on which all society and
all government has grown up.

Now it is plain, that as soon as we admit the doctrine of artificial
kindred--that is, as soon as we allow the exercise of the law of
adoption, physical purity of race is at an end. Adoption treats a man as
if he were the son of a certain father; it cannot really make him the
son of that father. If a brachycephalic father adopts a dolichocephalic
son, the legal act cannot change the shape of the adopted son's skull. I
will not undertake to say whether, not indeed the rite of adoption, but
the influences and circumstances which would spring from it, might not,
in the course of generations, affect even the skull of the man who
entered a certain _gens_, tribe, or nation by artificial adoption only.
If by any chance the adopted son spoke a different language from the
adopted father, the rite of adoption itself would not of itself change
his language. But it would bring him under influences which would make
him adopt the language of his new _gens_ by a conscious act of the will,
and which would make his children adopt it by the same unconscious act
of the will by which each child adopts the language of his parents. The
adopted son, still more the son of the adopted son, became, in speech,