Reference for Chullin 175:6

לא קלין שרץ וחמורין זב

- No; 'light uncleanness' is that of a reptile, and 'grave uncleanness' is that of a man that has a flux.<span class="x" onmousemove="('comment',' But the liquids (excepting blood) that issue from a corpse are clean.');">⁴</span>

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