Reference for Niddah 118:51

מה לי א"ר שמעון

R. Simeon? Did R. Simeon maintain his view only where she is standing, since her passage is then compressed.<span class="x" onmousemove="('comment',' Lit., 'the world is pressed for her'. As a result of the narrowness of the passage blood from the menstrual source might well be presumed to issue together with the returned urine, and since this presumption almost amounts to a certainty there remains no more than one doubt, as to whether the blood emanated from the man or the woman, which well justifies R. Simeon's ruling that the blood is unclean. ');">⁴⁷</span>

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