Niddah

SINCE THEY COHABIT WITH MENSTRUANTS etc. Do they all  cohabit with menstruants? — R. Isaac of Magdala replied: This was learnt about married persons only. BECAUSE [THEIR WIVES] CONTINUE [UNCLEAN FOR SEVEN DAYS] ON ACCOUNT OF A DISCHARGE OF ANY BLOOD etc. It was taught: R. Meir stated, If they continue [unclean for seven days] on account of a discharge of any blood,  is not this  rather an important safeguard for them? But the fact is that when they observe a discharge of red blood they treat it as supplementary to a previous discharge of yellow blood.  Another explanation: She includes the day on which her discharge ceases  in the number of the seven days.  Rami b. Hama demurred: Why indeed should she not count it,  and why should not we also count it,  seeing that we have an established rule that part of a day is regarded as the whole of it? — Raba retorted: If so,  how could it be possible for an emission of semen to cause the counting  after a zibah to be void seeing that a part of the day is to be counted as the whole of it?  If one had observed the discharge in the middle of the day the law might indeed be so,  but here we might be dealing with one who observed the discharge near sunset?  — Could it then definitely be assumed that  the Scriptural text was written only [in regard to a discharge] near sunset? — Yes; you must indeed allow the text to be so explained, for it  forces this interpretation upon itself. Rami b. Hama enquired: If a woman  ejected some semen;  does she cause her counting  after a zibah to be void? Is she regarded as one who observed an emission of semen and causes, therefore, the counting  to be void