Previous daf

1)

(a) Had the box not been examined, then even Chizkiyah would concede that it is Tamei retroactively. When he says that it is Tahor retroactively, he is referring to a box that was examined, and which now has a Chezkas Taharah, up to the time that the Sheretz is discovered.
But Rebbi Yochanan suspects that a Sheretz may have fallen into the box the moment he finished examining it, and that is therefore, no Chezkas Taharah.

(b) Even though a Nidah examines herself every morning and evening, nevertheless, since blood appears regularly, it is as if she was not examined (the Gemara gives a similar Sevara a little later, where it says that, even though a woman is covered - like a covered box, where nothing enters from the outside, nevertheless, that covering is ineffective, since blood appears regularly.)

(c) The Gemara explains that certainly, Rebbi Yochanan would agree with Chizkiyah if the covering was not used - i.e. if the box remained covered until they had finished with it, when they would empty it. However, that is not the case. It speaks when, from time to time, they take from the box and put into it, and, when they do, they remove the covering.
Rebbi Yochanan suspects that the Sheretz may have fallen into the box whilst they were putting into it or taking from it (not dafka when they have finished with it, like Chizkiyah maintains).

3)

(a) The Mishnah in Taharos writes 'Naga Echad ba'Layla, ve'Eino Yodei'a Im Chai Im Meis, u'Lemachar Hishkim u'Metza'o Meis, Rebbi Meir Metaher, *va'Chamamim Metam'in'*. From here we see that we go after the present, and do not contend with the past.
And a Beraisa, explaining this Mishnah, adds: 'Ke'sha'as Metzi'asan, *u'vi'Mekom Metzi'asan' - to teach us that not only do we go after the present time, but also after the present place, and we do not contend with the past, leaving us with a Kashya on Rebbi Yochanan.

( b) The Gemara explains that when the Mishnah in Taharos says that we go after now, it means to burn the Terumah if the Tamei object then touched Terumah); Consequently, when we infer from their words, that we do not contend with the past, it means to declare Vaday Tum'ah, to burn Terumah on it - but Safek Tamei it is, like Rebbi Yochanan said.
As for the various Mishnahs ans Beraisos, which go after the present and do not contend with the past: that is indeed the case with time, which is a strong Chazakah and which we therefore place on a Chezkas Vaday, even to burn when it is la'Chumra, and to declare completely Tahor when there is a Chezkas Taharah.
But when it comes to place - to place on a Chazakah, and not to be Machzik Tum'ah from one place to another, Rebbi Yochanan holds that that is a weaker Chazakah - sufficiently strong not to burn Terumah on subsequent contact with it, but not to declare it Tahor.

(c) When the Beraisa in Taharos, finds ways to declare the loaf Tahor, and is not Machzik Tum'ah from place to place even Lislos (and not to burn), that is only because we can ascribe the loaf's present position to a passer-by, who, we assume, took it from the board, and placed it on the floor, awy from the Tamei garment.

(d) Rebbi Elazar established that the Beraisa is speaking on a slope, so that the loaf could indeed have dropped onto the garment, and then rolled off it again.

(e) We only contend with the possibility that a *human being* moved the loaf (perhaps to prevent it from becoming Tamei?), but not on *animals* moving it.

4) We only say 'Safek Tum'ah bi'Reshus ha'Yachid Tamei', by a person, whom we can subsequently ask whether he became Tamei or not, but not by an object. Alternatively, we only go le'Chumra, by a Tum'ah d'Oraysa, but not by a Tum'ah de'Rabbanan, and in this case, the garment is only Tamei de'Rabbanan. How do we prove that?
Because the Beraisa calls the garment 'Madaf', which suggests a lighter form of Tum'ah - as we find in the Pasuk "Kol Aleh Nidaf" (the voice of a *fleeting leaf*).

5) The truth is that there is no Chidush at all in saying that 'mi'Pekidah li'Pekidah' detracts from 'Mei'es Le'es'. That is obvious! The Mishnah only mentions it because it mentions that 'Mei'es Le'es' detracts from 'mi'Pekifah li'Pekidah', which *is* a Chidush.

6)

(a) Had the Rabbanan's reason been because a woman is aware when she sees blood, like Raba suggested, then why should she even be Temei'ah twenty-four hours retroactively?

(b) The reason that Raba made the suggestion was in order to test Abaye's reaction - to sharpen his wits.

(c) Of course a 'Mei'es Le'es' is two Onos. However, a woman inevitably loses one Onah, from the morning till the evening (or vice-versa). What Shmuel meant was that the Chachamim instituted that a woman who failed to examine herself, is penalized to lose one *extra* Onah.

(d) A woman who did not examine herself for a few days, and who then saw blood the following afternoon, is Temei'ah since yesterday afternoon - which is really a part of three Onos: (retroactively) from now till morning, from morning till last night, and from last night till yesterday afternoon.

But did we not say that Chazal decreed one extra Onah, not two?
To which the Gemara replies that Chazal wanted to make a fixed time for all women, so as not to penalize different women with different time periods; so they said twenty-four hours (which is usually around two Onos).

(a) The Gemara's second answer is that Chazal decreed twenty-four hours for a woman who was lax, in order that 'the sinner should not benefit from her sin' - meaning that were Chazal to have decreed exactly two Onos, then a woman who had failed to examine herself for some days, and then did so in the morning, she would lose a full twenty-four hours. So what would she do? She would wait until the afternoon before examining herself, in which case she would only be Asur - assuming she sees blood - from the previous nightfall. In this way, she will have benefited by her sin.
That is why Chazal instituted that all women are obligated to wait twenty-four, thereby making sure that no sinner will be able to gain.

(b) The difference between the two answers is that, according to the first answer, every woman becomes Temei'ah twenty-four hours in retrospect. But according to the second answer, a woman who was unable to examine herself due to extenuous circumstances, will only lose two full or part Onos, but not twenty-four hours.

(a) The Rabbanan (alias Rebbi Eliezer) hold, that it is only by four women (we will see later who those four women are) that we say 'Dayah Sha'atah'.

(b) The Gemara at first suggests that the Rabbanan argue with Rebbi Dosa only in the case of women who do not have a Veses, whereas our Mishnah speaks about women who do, and there, the Rabbanan agree that we say 'Dayah Sha'atah'.

(a) With regard to a woman who has a Veses, we say '*Dayah Sha'atah*', when she sees blood at the time of her Veses. Nevertheless, were she to have seen a bloodstain at that time and not actual blood, she would be *Temei'ah retroactively* - in spite of the fact that it is not logical to be more stringent by a Kesem than by an actual sighting. Why is that?
Because even by sighting blood, retroactive Tum'ah is applicable to her, in a case where she sees blood outside the time of her Veses.

(b) The Beraisa could go like Rebbi Dosa, if we were to say that Rebbi Dosa agrees with the Rabbanan when she sees blood outside the time of her Veses, and their argument in confined to when she sees at the time of her Veses.

(c) It is obvious that one cannot say that Rebbi Dosa and the Rabbanan argue by a woman who sees blood outside the time of her period, and agree that, if she were to see blood inside the time, that she is Temei'ah retroactively, and at the same time hold that they argue when she sees blood at the time of her period, but agree that when she sees blood outside the time, that she is Temei'ah retroactively. It can only be the one or the other.

(d) The reason that the Gemara rejected its original contention and accepted the second one, is because of the principle that, whenever we have two such options, we also assume the one which is more strict.