Introduction to Nidah

1)

(a) 'Kol ha Nashim, Dayan Sha'atan' means that when a woman sees blood she is Temei'ah from that moment and onwards - and not retroactively.

(b) Hillel holds that the woman is Temei'ah retroactively since her last examination - as far as Terumah and Taharos is concerned.

(c) According to the Chachamim, she is Temei'ah retroactively, but only going back twenty-four hours, unless she examined herself within that time, in which case they agree with Hillel, that she is only Temei'ah from then onwards.

(a) A woman with a Veses means that her period arrives at regular intervals, in which case, everyone agrees that Dayah Sha'atah.

(b) 'Eidim' is the name given to the cloths a woman uses to examine herself before and after Tashmish.
A woman who used 'Eidim' has the same Din as one who made a regular examination, and it detracts from the twenty-four hours that she would otherwise be Temei'ah retroactively.

(c) Even in the cases when the woman is Temei'ah retroactively, her period of Nidus nevertheless begins only from the time that she sees blood.

4)

(a) In a case of Vaday Tum'ah, one burns the Terumah that has been touched by the Tum'ah, whereas in a case of Safek Tum'ah, one declares it Tamei, but does not burn it.

(b) We know that the Mishnah of Mikveh means Vaday Tamei, since it rules that the Taharos are Tamei, even in a public domain - (had it been only Safek Tamei, we would have applied the principle 'Safek Tum'ah bi'Reshus Harabim, Tahor'.)

(c) The difference between a Nidah who sees blood and a Mikveh which is found to be short of water, is that the Mikveh has *two* shortcomings (the Mikveh, which is now short of water, and the person or the vessels which had a Chezkas Tum'ah at the time when they were Toveled), which explains why it is Vaday Tamei according to both Hillel and Shamai; whilst in the case of the Nidah, there is only *one* (that there is now blood in front of us), and that is why Shamai considers her to be Tehorah and Hillel only Safek Tamei.

(a) If he discovers that his barrel of wine became sour, then for the first three days after his last examination we assume it to have still been good wine; but, from then on, it is Safek vinegar (and he can not rely on the Ma'asros that he separated during that period) - according to Rebbi Yehoshua ben Levi, the three days prior to his discovery, the wine is considered to have been definite vinegar, but before then, it is only a Safek.

(b) Whatever the case, this seems to clash with Shamai, in whose opinion we should place the wine on a Chazakah, and say that it only turned into vinegar now, when he discovered that it was sour.

(c) The Gemara resolves the problem as it did earlier, by differentiating between the case of the barrel of wine, where there are two shortcomings (the fact that it is now vinegar, and the fact that the Tevel which he is attempting to rectify with the contents of the barrel, has a Chezkas Tevel). Whereas in the case of our Mishnah, there is only one shortcoming; that explains why, according to Shamai, we are stringent by the barrel of Terumah, and lenient by the Nidah.

(d) And the reason that we consider the barrel to be only a Safek Tevel retroactively, whereas in the case of Mikveh, all the Taharos are Vaday Tamei, despite the fact that in both cases, there are two shortcomings, is no discrepancy either, because the author of the Mishnah concerning the barrel of Terumah is Rebbi Shimon, who learns, even in the case of Mikveh, that it is only Safek Tamei.