hat often "nothing unites the members of the rod but a vague
tradition of common descent."[1720] Whether individuals can break the
ties of kin, by voluntary act, is answered differently in different
societies. The Salic Franks allowed a man to do it by breaking his staff
(which was his personal symbol) in a ceremonial act.[1721] If kinship
depends on connection of the body of the child with that of the mother,
his nourishment by her milk is another ground of kinship. The Arabs
recognize this tie of a child to its foster mother. Later the child is
nourished by food shared with commensals. Hence the tie of commensality
forms a basis of social union like kinship.[1722]

+538. How mores are formed.+ The family groups which are in local
neighborhood have, in general, the same folkways as an inheritance, but
variations occur from varieties of character and circumstances. The
variations are life experiments, in fact, and they lead to selection. In
the community as a whole the mores of family life are selected,
approved, and established, and then handed down by tradition. It may be
believed that there is a common interest of the entire larger group in
the education and treatment of children, and that all the adults
recognize that interest more or less completely. The big group,
therefore, molds notions of consanguinity, and the sanctions of tribal
authority and public opinion coerce all to observe the modes of family
life which the ruling authority thinks most expedient for the group
interests.

+539. Family and marriage.+ The family institution must have preceded
marriage. In fact, marriage appears, in ethnography and history, as the
way of founding a family and as molded by the family mores existing in
the society.

+540. Goblinism and kinship. Blood revenge.+ Integration of kin
relations was produced by goblinism. This furnished an interest which
impelled to development of the kin idea. If a man was murdered, his
ghost would seek revenge, just as a man while alive would have sought
revenge for a smaller injury. The ghost was dangerous to two persons or
classes of persons, the murderer and those near the corpse. The latter
would be, almost always, his kinsmen. It behooved the latter, therefore,
if they wanted to appease the ghost and save themselves, to find the
murderer and to punish him. Hence the custom of blood revenge. It was
not due to kin notions, but to goblinistic notions. Kin only defined
those who came under the