Volume 2: 1771 Edition of the Encyclopedia Britannica!
Impurity, in the law of Moses, is any legal defilement. Of these there
were several sorts; some were voluntary, as the touching of a dead body, or any
animal that died of itself, or any creature that was esteemed unclean; or the
touching things holy, by one who was not clean, or was not a priest; the
touching one who had a leprosy, one who had a gonorrhoea, or who was polluted by
a dead carcase, etc. Sometimes these impurities were involuntary, as when
any one inadvertently touched bones, or a sepulchre, or any thing polluted; or
fell into such diseases as pollute, as the leprosy, etc.