idea out of which the custom of blood revenge arose. Blood
atonement was a notion in goblinism. It was one of the very earliest
cases we can find in which there was a notion of duty and social
obligation. The kin were those on whom the duty fell. The strong
sympathy of men of the same kin was a consequence, not a cause, but it
superseded, later, the original cause. At first, the play of revenge
gave satisfaction to wounded vanity, but that could only last while the
case was personal and close, not when the cases and the obligations were
remote and institutional. Another remoter, and perhaps unforeseen,
consequence was the deterrent effect on crime. The law of retaliation
also, "an eye for an eye," was a _law_. It had a primitive and crude
justice in it. It has come down to our own time in "reprisals" as
practiced in international quarrels, which include also the solidarity
of responsibility of all in a group for the torts of each member of it.
By producing a solidarity of interest on both sides blood revenge helped
to produce a social philosophy. It also made each interest group a peace
group inside, because only by being a peace group could it conserve all
its force. Thus the war interest against outsiders and the interest of
concord inside worked together to produce order, government, law, and
rights.

+553. Alleviations of blood revenge.+ The Arabs, in their efforts to
supersede blood revenge, tried compurgation, tribunals, payments in
composition, banishment, and arbitration. Many tribes which have adopted
Mohammedanism still practice blood revenge.[1765] Amongst the Kabyles a
man falls under it if he kills another by accident, or by the fault of
the victim, or in preventing a crime.[1766]

+554. The king's peace.+ In the history of civilization the devices to
do away with blood revenge are those which have been incidentally
mentioned. The last means of suppressing all forms of private war was
the king's peace. In modern states due respect to the king required that
there should be no quarreling or fighting in his presence. His presence
was interpreted to mean in or near his residence, his court, and his
environs. Then his peace was interpreted to cover his highroads, and his
jurisdiction was presently held to go as far as his peace, because he
must have authority to enforce his peace. When small states were united
into big ones the peace bond had to be extended over the larger unit.
Gradually all petty jurisdictio