Posse Comitatus, a Latin expression, signifies the whole coercive power of a county called out in the case of a riot, and embraces all males over 15 except peers, ecclesiastics, and infirm persons. These may be summoned by the sheriff to assist in maintaining the public peace, enforcing a writ, or capturing a felon; but usually the constabulary is sufficient for these duties.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Positivism * Post Restante