obligation. In this way kin became a tie of
mutual offense, defense, and assistance, and kin groups were formed into
societies,--we-groups or in-groups,--inside of which there was
comradeship, peace, law, and order, while the relation to all out-groups
was one of suspicion, hostility, plunder, and subjugation if possible.
The primary notion of kin was embodied in formulae about blood,--which
were only figures of speech,--which have come down to us, so that
propositions about blood are used now to express our notions of kinship,
heredity, etc. In fact, according to modern embryology, not a drop of
blood passes from either parent to the offspring. Superstitions about
blood (seat of the soul or life, etc.) helped to develop the notion of
kin. The primitive idea is that the ghost of a murdered man can be
appeased only by blood. The blood of Abel cried unto God from the
ground. Some peoples go out to kill anything, in order that blood may be
shed and so the ghost may be satisfied.

+541. Procreation. Forms of the family.+ The notion of kin was so
elastic that various conceptions of procreation have been grafted upon
it, and various ways of organizing the family, or of reckoning kinship,
have been connected with it. Mores grow upon the notions of kinship.
They dictate modes of behavior and ideas of right and duty, and train
all members of the society in the same. The relation of father and child
is known to few persons, perhaps only to two. Kinship through the
father, therefore, seems to uncivilized people far less important than
kinship through the mother. When the father relationship is regarded as
the real tie and is made the norm of kin groups, great changes are
produced in the mores of the mother family.

+542. Notions about procreation and share in it.+ It is difficult
to see how savage men could have got any idea of procreation. The
ethnographical evidence is that they have no idea, or only a most
vague and incorrect idea, of the functions of the parents. The
Australians think that an ancient spirit enters into a baby at
birth, enlivens it, and is its fate. This notion interferes with
ideas of sexual conception. So we are told that the Dieyerie
women do not admit that a child has only one father, and say that
they do not know whether the husband or the _pirauru_ is the
father.[1723] The highest tribes in Australia say that "the
daughter emanates from her father solely, being only nu