1) THE CASE OF "BA'IN MIN HA'DERECH"
OPINIONS: The Mishnah states that men who are "Ba'in Min ha'Derech" -- "coming from the road" -- may assume that their wives are Tahor. In the Gemara, Reish Lakish quotes Rebbi Yehudah Nesi'ah who says that this applies only when she is "within the days of her Onah" -- that is, before the time of her Veses arrives. Rav Huna says that Rebbi Yehudah Nesi'ah refers to a case in which the husband leaves after his wife has already become Tahor from her last Tum'as Nidah early in the month, and he returns before the time at which she anticipates her next Veses. He may assume that his wife has not seen Dam Nidah in the interim, as she usually does not see Dam Nidah during these days. The Gemara comments that Rav Huna clearly maintains that Vestos are mid'Oraisa; when the time arrives at which a woman normally sees Dam Nidah, she is assumed to be Tamei unless we know otherwise.
Rabah bar bar Chanah disagrees with Rav Huna and explains that Rebbi Yehudah Nesi'ah refers even to a case in which the husband returns when his wife has already reached the time of her Veses. He still may assume that his wife is Tahor. The Gemara says that Rabah bar bar Chanah clearly maintains that Vestos are mid'Rabanan; it is only mid'Rabanan that we assume that a woman is Tamei when the time of her Veses arrives.
Rabah bar bar Chanah's opinion needs clarification. G-d-fearing Jews certainly observe Mitzvos mid'Rabanan just as they observe Mitzvos d'Oraisa. Why should a man disregard the Tum'as Nidah d'Rabanan of his wife when he comes home from a trip and she is prohibited to him mid'Rabanan?
(a) The RASHBA quotes an explanation that Rabah bar bar Chanah refers to a case in which the wife is expecting to see Dam Nidah. Why, then, is she not considered Tamei mid'Rabanan? The RITVA writes that according to this explanation, there is a special dispensation of the Rabanan for one who comes home from a trip. The Rashba adds that this dispensation overrides the prohibition of Samuch l'Vestah (see Insights to Shevuos 18b), according to Rabah bar bar Chanah. The precedent for this is the Gemara in Yevamos (62b) which says (according to some opinions) that one is obligated to be with his wife before he departs on a trip, even though she is Samuch l'Vestah.
The Ritva states that even though this explanation seems "nearer (to the truth) and better than a lot of other explanations," it is not appropriate to rely upon this leniency for several reasons. First, such a significant leniency should have been explicitly stated, just as the Gemara in Yevamos explicitly states the leniency of one who is departing on a trip. Second, not everyone agrees that the Gemara in Yevamos actually permits relations upon embarking on a trip Samuch l'Vestah (see TOSFOS to Yevamos 62b, DH Chayav, in the name of RABEINU SHIMSHON who says that the Gemara means that one should verbally placate his wife, but should not be involved with her physically).
(b) The Ritva therefore gives a different explanation. He writes that Rav Huna and Rabah bar bar Chanah argue in a case in which the husband returned home after his wife's most recent Veses had passed, and his wife had not checked herself at the time to see if she in fact became a Nidah. Rav Huna maintains that Vestos are mid'Oraisa, and therefore even if she checks after the time of her Veses and the Bedikah is clean, we assume that there was Dam at the time of her Veses and she is Tamei. Rabah bar bar Chanah argues that even after her Veses has passed and she did not do a Bedikah, she can make up for it by doing a Bedikah when her husband comes home. If the Bedikah is clean, she is assumed to be Tahor. Moreover, the Ritva says, the husband may tell her before his return that his intention is to be with her upon his return, and he then may assume that she examined herself during her Veses and did not find Dam Nidah. As long as she does not say anything to the contrary she is presumed to be Tahor, as the Gemara says earlier (12a), "Tevi'asah Zo Hi Bedikasah" (if there was a chance that she became Tamei, upon hearing his intentions she would do a Bedikah first and find out for certain).
(c) TOSFOS (DH Afilu) and the TOSFEI HA'ROSH explain that Rabah bar bar Chanah refers to a husband who returns home after a span of time passed during which his wife would have been able to go to the Mikvah if she had become a Nidah. The possibility that she might have already gone to the Mikvah negates the possibility that she might have seen Dam at her usual time, because even if she did see Dam, she could have gone to the Mikvah. Therefore, she is assumed to be Tahor.
Rav Huna argues because he maintains that Vestos are mid'Oraisa, and we do not assume that the woman might have seen Dam, but rather we assume that she certainly saw Dam. The possibility that she went to the Mikvah does not give her a status of being Tahor. Therefore, she is presumed to be Tamei unless she explicitly says that she is Tahor. (Y. MONTROSE)
2) WHEN DOES A WOMAN HAVE A "CHEZKAS TAHARAH"
OPINIONS: The Gemara stipulates that the Chezkas Taharah that every woman has, which permits her to be with her husband, applies only before the time of her Veses. Once the time of her Veses arrives, she cannot be assumed to be Tahor without doing a Bedikah and informing her husband that she is Tahor.
(a) The RAMBAM (Hilchos Isurei Bi'ah 4:9) rules that this applies only when the woman has a fixed time for seeing Dam (Veses Kavu'a). If she has no fixed time, then she does not have a Chezkas Taharah and she must examine herself and inform her husband that she is Tahor.
(b) TOSFOS and the RASHBA (DH Hachi Itmar) disagree. They rule that even a woman who has no Veses Kavu'a still has a Chezkas Taharah. The Rashba adds that had there been such a difference between a woman with a Veses Kavu'a and a woman without a Veses Kavu'a, the Gemara would have suggested that this is what Rav Huna really meant to say when he made a distinction between Veses Kavu'a and Veses she'Eino Kavu'a.

15b----------------------------------------15b

3) A KOHEN WHO LOOKS INTO A PIT TO EXAMINE A "NEFEL"
OPINIONS: The Gemara relates an incident involving the maidservant of a "Masik." TOSFOS translates "Masik" as an olive presser. (RASHI in Avodah Zarah (42a) has the Girsa of "Matzik," or a tough person.) After giving birth to a Nefel (a baby that did not live for thirty days), she threw the baby into a pit. A Kohen bent over the pit and looked inside to see whether the baby was a male or female in order to determine how many days of Tum'ah and days of Taharah the woman should observe.
Was it proper for the Kohen to look into the pit to see the dead baby?
(a) TOSFOS (DH u'Va Kohen) quotes RABEINU TAM who says that the Kohen who did this was a Shoteh (an ignoramus). Even if the Nefel was one of the seven relatives for whom a Kohen is permitted to become Tamei, the Toras Kohanim teaches that this allowance applies only for relatives who are not in the category of a Nefel. In addition, the only leniency for a Kohen to become Tamei for one of these seven relatives is if he is becoming Tamei for the purpose of the dead person (attending to his funeral, carrying his body, burial). A Kohen is not permitted to become Tamei solely to serve someone else's convenience, as in the case of the Gemara here in which he became Tamei in order to ascertain the schedule of the maidservant's Yemei Nidah and Yemei Taharah. This is also the approach of the TOSFEI HA'ROSH.
RASHI (DH Im Zachar Hu) begins by saying that the Kohen was a wise Kohen who was an authority in Halachah. He looked into the pit either because he wanted to tell the woman the schedule of her Yemei Nidah and Yemei Taharah, or because she lived in his house and handled the Terumah he received. He wanted to make sure that the woman would handle, and refrain from handling, his Terumah for the appropriate number of days.
Rashi continues and adds that others give a third reason for the Kohen's actions. They explain that the Kohen wanted to know if the time at which the woman would be fit to bring her Korban Yoledes would occur during his Mishmar.
However, Rashi rejects all of these explanations. On the last explanation he asks that no Kohen would risk becoming Tamei in order to find out whether an Olas ha'Of (or Chatas ha'Of, see HAGAHOS MAHARAV RENSBERG) would be brought during his upcoming Mishmar. Moreover, the woman does not have a set time at which she must bring her Korban. On the first explanation, Rashi asks that these are not valid reasons to permit a Kohen to become Tamei.
Rashi therefore concludes that the Kohen was either an ignoramus, or he was a child who was sent by the woman to check the identity of the child.
(b) Rashi in Avodah Zarah (42a, DH Kohen) quotes only the first explanation (that the Kohen was a Posek who wanted to tell the woman how many days she needed to observe as Yemei Nidah and Yemei Taharah). How does Rashi there answer all of the questions that he asks here on this explanation?
The ARUCH LA'NER quotes the MEI NIFTO'ACH who was unsure about whether a dead servant is considered to have Tum'as Mes. If a servant indeed does not have Tum'as Mes (the Aruch la'Ner concludes that this is the opinion of Rebbi Shimon bar Yochai), then it is possible that the Kohen, who was wise and not an ignoramus, followed this view, and, therefore, he was not concerned about any issues of Tum'as Mes. (See also CHASAM SOFER here at length). (Y. MONTROSE)

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