rs' wives.[1710] The Arabs were convinced of the
evil of marriage between cousins.[1711]

+526.+ A mediaeval traveler reports of the Mongols that they paid no heed
to affinity in marriage. They took two sisters at once or in succession.
The only limitation was that they must not marry mothers, daughters, or
sisters by the same mother.[1712] In Burma and Siam, at least until very
recent times, in the royal families of the different subdivisions
brothers and sisters married.[1713]

+527.+ In Russia, in the seventeenth century, men in the government
service who were often sent out on duty and had no homes, and whose
incomes were small, were reproached by an ecclesiastic with the fact
that they lived in vice with their mothers, sisters, and
daughters.[1714] Marriages between persons related by blood are frequent
in Corsica and are considered the most auspicious marriages.[1715]

+528.+ The Kabyles stone to death those who voluntarily commit incest
and the children born of incestuous unions. The taboo, in their usage,
includes parents and children-in-law, brothers and sisters-in-law, and
foster brothers and sisters.[1716]

+529.+ In 1459 there died at Arras a canon, eighty years old, who had
committed incest with his daughters and with a granddaughter whom he
had had by one of them.[1717]

+530. Where the line is drawn, and why.+ The instances show that the
notion of incest is by no means universal or uniform, or attended by the
same intensity of repugnance. It is not by any means traceable to a
constant cause. Plutarch[1718] discussed the question why marriages
between relatives were forbidden by the traditional mores of his time.
He conjectured various explanations. Fear of physical degeneration is
not one of them. We must infer that such consequences had not then been
noticed or affirmed. We have found cases in which no taboo existed and
cases in which close intermarriages are especially approved. An
operation of syncretism, when different usages and ideas have been
brought together by conquest and state combinations, must be allowed
for. In some cases a great interest was thought to be at stake; in other
cases no importance was attached to the matter. The mores developed
under the notions which got control by accident or superstition. There
was no rational ground for the taboo, and none even blindly connected
with truth of fact, until the opinion gained a footing that close
intermarriage was unfavorable to the numbe