Reference for Niddah 118:8

אמר שמואל

and brought back blood with it. But then, even where SHE WAS SITTING why should it not also be assumed that the urine had returned to the source and brought back blood with it? — Samuel replied: The reference is to a woman who discharges in a gush.<span class="x" onmousemove="('comment',' Sc. in the natural manner, no strain being involved in the process. Only when a strain is involved (as where the woman is standing or where the discharge is slow) is it likely for the urine to return to the source and to re-issue mixed with blood, but not where the discharge is flowing normally and easily. ');">⁶</span>

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