We are here moving in a realm of ideas prevailing in ancient Israel respecting holiness, uncleanness and sin, which are ceremonial and not ethical; see especially Robertson Smith's Religion of the Semites, 2nd ed., p. 446 foll.
(additional note B.) on holiness, uncleanness and taboo.
As to uncleanness must have been less precise.
On the one hand, since that which is tabooed is held to punish the taboo-breaker by a sort of mystic infection, taboo comes to stand for uncleanness and sin.
Taylor, Te Ika a Maui, 165), or when uncleanness is removed as if it were a physical secretion by washing, wiping and so forth, it is hard to say whether what we should now call a " material " nature is not ascribed to the sacred, more especially when its transmissibility after the manner of a contagion is the trait that holds the attention.