Reference for Chullin 175:5

מאי לאו קלין שרץ וזב וחמורין מת

or of a man that has a flux, and 'grave uncleanness' that of a corpse!<span class="x" onmousemove="('comment',' A corpse is regarded as the gravest form of uncleanness because it is the generator of a primary source of uncleanness, - 'the father of a primary source of uncleanness'. Now this Mishnah teaches that the liquid that issues from a corpse is unclean and conveys uncleanness, thus contrary to the previous teaching.');">³</span>

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