the art of purging, scouring, or purifying a thing, by separating, or carrying off any impurities found therein. Thus,

In pharmacy, purgation is the cleansing of a medicine by retrenching its superfluities. In chemistry, it is used for the several preparations of metals and minerals intended to clear them of their impurities, more usually called purification and refining.

In medicine, purgation is an excretory motion arising from a quick and orderly contraction of the fibrous fibres of the stomach and intestines, whereby the chyle, corrupted humours, and excrements lodged therein, are protruded farther and further, and at length quite excluded the body by stool. See Materia Medica.

Law, signifies the clearing a person's self of a crime of which he is suspected and accused before a judge. This purgation is either canonical or vulgar. Canonical purgation is prescribed by the canon-law, and the form thereof in the spiritual court is usually thus: The person suspected takes his oath that he is innocent of the crime charged against him; and at the same time brings some of his neighbours to make oath that they believe he swears truly. Vulgar purgation was anciently by fire or water, or else by combat, and was practised here till abolished by our canons. See Battle, in law; Ordeal, &c.