1) "MIS'ASEK B'KODSHIM"
OPINIONS: The Gemara proves that one who is "Mis'asek" with Kodshim invalidates the Kodshim. What is the case of "Mis'asek b'Kodshim"?
(a) TOSFOS (DH Minayin) explains that Mis'asek b'Kodshim means that the person intended to cut the animal's Simanim but did not intend to perform Shechitah and effect any Halachic change. Such an act would result in a valid Shechitah in the case of Chulin, but in an invalid Shechitah in the case of Kodshim. For Kodshim, one must have specific intent to perform the Mitzvah of Shechitah.
Tosfos adds that another type of Mis'asek involves a case in which a person slaughters Kodshim while thinking that he is slaughtering an animal of Chulin. This is also a type of Mis'asek b'Kodshim. The RASHBA gives both explanations, citing the latter explanation in the name of RABEINU YITZCHAK. (See also Tosfos to Zevachim 47a, DH Minayin.)
(b) RASHI (DH Minayin) implies that Mis'asek b'Kodshim involves an act done with no intention to perform that act. Rashi gives as an example of Mis'asek b'Kodshim a case of one who lifted up or threw a knife, and by chance the knife cut the Simanim of an animal in the manner of Shechitah. The person had no intention to cut the animal. This implies that, according to Rashi, if the person had intended to cut the animal, but without intent to effect a Halachic change through Shechitah, the Shechitah of the Korban would be valid.
Tosfos has difficulty with Rashi's explanation. The Gemara later (31a) says that the Rabanan maintain that even for the Shechitah of an animal Chulin to be valid, the person who performs the Shechitah must have in mind that he is cutting the Simanim of an animal. Why, then, does the Gemara here need a special verse to teach that the same applies to Kodshim?
The Rashba addresses the problem with Rashi's explanation. The Rashba says that according to Rashi, it must be that the Gemara here is asking for a source that Mis'asek b'Kodshim is Pasul only according to Rebbi Nasan. Rebbi Nasan argues with the Rabanan and says that one does not need intention to cut at all when he performs an ordinary Shechitah of Chulin. Rebbi Nasan maintains that even if one intended to throw a knife into a wall, and the knife happened to cut the Simanim of an animal in the manner of Shechitah, the Shechitah is valid. According to Rebbi Nasan, a source indeed is necessary to teach that this type of Shechitah is Pasul for Kodshim. (The Rashba, however, continues by giving a different explanation which explains how the Gemara here can also be compatible with the opinion of the Rabanan.)
However, there is another difficulty with the explanation of Rashi. Rashi in Menachos (110a, DH Minayin) explains that Mis'asek b'Kodshim refers to one who intended to cut one item, and he happened to cut another item which was Kodshim, as Tosfos here explains. Why does Rashi there give a different explanation from the one he gives in Menachos?
HA'GAON RAV GEDALYA RABINOWITZ shlit'a, the Manostrishtcher Rebbe, suggests that Rashi understands that the Gemara here is a continuation of the previous Sugya (12b), in which Rava clearly states that the Mishnah (2a) is expressing the view of Rebbi Nasan. Since the Gemara continues with questions according to the view of Rebbi Nasan, it seems that the main question of the Gemara is how Rebbi Nasan knows that Mis'asek b'Kodshim is Pasul. This is consistent with the words of the Rashba cited above. The Rashba clearly states that Rashi understands that the Gemara here is discussing the view of Rebbi Nasan. (It is important to note that, unlike Tosfos who says "but this is difficult" about the suggestion that the Gemara's question is only according to Rebbi Nasan, the Rashba does not use any term of doubt when he states that Rashi understands that the Gemara's discussion is according to Rebbi Nasan.) The ROSH YOSEF indeed answers the questions of Tosfos on Rashi by stating that Rashi understands that the Gemara's question is according to Rebbi Nasan. In contrast, Rashi in Menachos has no reason to assume that the Gemara is asking its question according to Rebbi Nasan, and therefore Rashi there explains the case of Mis'asek b'Kodshim in a way that is compatible with the view of the Rabanan as well. (-Heard from the Manostrishtcher Rebbe at the first Grand Siyum of Kollel Iyun Hadaf.)
(The TIFERES YAKOV asks how Tosfos could have questioned Rashi's explanation, when it is obvious that Rashi understands that the Gemara is discussing the view of Rebbi Nasan. The Tiferes Yakov, therefore, explains Tosfos' question in an entirely different manner. See there at length.) (Y. MONTROSE)
2) THE "TUM'AH" OF A NOCRHI'S "SHECHITAH"
OPINIONS: The Mishnah states that a Nochri's Shechitah renders the animal a Neveilah, and the dead animal is Metamei b'Masa. Is the status of Neveilah of this animal d'Oraisa, such that it is Metamei mid'Oraisa, or it is only Metamei mid'Rabanan?
(a) The RA'AVAD and other Rishonim assert that since the Shechitah is invalid, the animal clearly is considered like any Neveilah and is Metamei mid'Oraisa.
(b) The RAMBAM (Hilchos She'ar Avos ha'Tum'ah 2:10) maintains that this Tum'ah is only mid'Rabanan.
The Ra'avad strongly disputes the Rambam's opinion, insisting that the animal must be a Neveilah mid'Oraisa if the Nochri's Shechitah is invalid.
The KESEF MISHNEH explains that the Rambam's ruling is based on his own opinion elsewhere. The Rambam (Hilchos Shechitah 4:11, based on Shemos 34:15) rules that a Nochri's Shechitah is invalid only mid'Rabanan. Only if the Nochri was an idol-worshipper is his Shechitah invalid mid'Oraisa. Consequently, the animal that an ordinary Nochri slaughters is not a Neveilah at all. If the Nochri is an idolater, then his Shechitah is prohibited mid'Rabanan as a safeguard to prevent Jews from becoming too close to idolaters, and not because the animal is a Neveilah.
All other Rishonim argue that the Shechitah of any Nochri is invalid, since a Nochri is not a "Bar Zevichah" -- he is not qualified to perform Shechitah (see TOSFOS to 3b, DH Kasavar, and ROSH 1:7). Therefore, his Shechitah renders the animal an actual Neveilah.
3) DERIVING BENEFIT FROM THE CARCASS OF AN ANIMAL SLAUGHTERED BY AN IDOLATER
QUESTION: The Mishnah states that a Nochri's Shechitah renders the animal a Neveilah, and the dead animal is Metamei b'Masa. The Gemara points out that the carcass of the animal is not Asur b'Hana'ah, and one may derive benefit from the carcass (such as by selling it). There is no concern that the Nochri who slaughtered the animal intended to slaughter it for his Avodah Zarah, because, as Rav Nachman explains in the name of Rabah bar Avuha (13b), "there are no fervent idolaters among the nations today" -- the idolaters of today serve idols only out of habit, and not seriously.
The Gemara implies that in a case of a doubt about whether the Nochri who slaughtered the animal is a fervent idolater, the animal would be Asur b'Hana'ah out of doubt. Why, though, should the animal be Asur b'Hana'ah? Before the animal was slaughtered, one was permitted to derive benefit from it. Accordingly, the animal has a "Chezkas Heter," a Chazakah that it is permitted for Hana'ah! Why, then, in the case of a doubt about whether the Nochri slaughtered it for Avodah Zarah, should the animal be Asur b'Hana'ah? (REBBI AKIVA EIGER; MELO HA'RO'IM)
ANSWER: REBBI AKIVA EIGER answers as follows. The Gemara in Avodah Zarah (34b) says that Rebbi Meir prohibits the cheese of the town of Onyaki because most of the calves slaughtered in that town are slaughtered for Avodah Zarah. Although Rebbi Meir usually is stringent and takes into account a "Mi'ut" (minority), and thus he should prohibit the cheese of Onyaki even if only a minority of the calves there are slaughtered for Avodah Zarah, in this case Rebbi Meir requires a Rov in order to prohibit the cheese. Without a Rov, there would be a "Mi'uta d'Mi'uta" (and Rebbi Meir agrees that there is no concern for a "Mi'uta d'Mi'uta") -- all of the calves in the town are a Mi'ut of the animals in the town, and the calves that are slaughtered for Avodah Zarah are a Mi'ut of the calves in the town.
TOSFOS there (DH Iy Amart) asks that even if a majority of the animals are slaughtered for Avodah Zarah, one should be permitted to derive benefit from the carcasses according to Rebbi Meir, because the animals have a "Chezkas Heter" since deriving benefit from them when they were alive was permitted. Tosfos answers that the "Chezkas Heter" in this case is weakened because some of the calves certainly were slaughtered for Avodah Zarah, and the calves from which this piece of cheese was made might be those calves.
The intention of the Gemara may be understood based on the words of Tosfos there. Since there definitely are some fervent idolaters among the Nochrim, the "Chezkas Heter" which permits benefiting from the animal does not permit the carcass after it has been slaughtered by a Nochri who might have slaughtered it for Avodah Zarah. The possibility that one of the fervent idolaters that exist in the world slaughtered it for Avodah Zarah must be taken into account, and thus it is Asur b'Hana'ah. (See RASHASH.)

13b----------------------------------------13b

4) "SHECHITAH" AT NIGHT
OPINIONS: The Mishnah states that a Shechitah performed at night and a Shechitah performed by a blind person are valid. The Gemara infers from the wording of the Mishnah that the Mishnah means that the Shechitah is valid only b'Di'eved, but l'Chatchilah one should not slaughter an animal at night, and a blind person should not slaughter an animal. The Gemara asks that the Mishnah contradicts the Tosefta which strongly implies that Shechitah may be done at night even l'Chatchilah. The Gemara answers that the Tosefta is discussing a case in which one has a torch in front of him which provides a sufficient amount of light to enable him to slaughter the animal properly.
What is the reason why one should not perform Shechitah at night when he has no torch in front of him?
(a) RASHI (DH l'Chatchilah Lo) explains that Shechitah should not be performed at night because of the concern that the Shochet might not cut a majority of the Simanim, and he will not be aware of this because of the darkness.
The SHITAH MEKUBETZES questions Rashi's explanation. The Gemara earlier (9a) establishes that one is required to examine the Simanim after Shechitah in order to ascertain that a majority of the Simanim were cut during the Shechitah. If one fails to examine the Simanim after Shechitah, the meat is rendered unfit to eat. If the problem of slaughtering without a torch is that one will not examine the Simanim, then why does the Mishnah say that b'Di'eved the Shechitah is valid? It should not be valid at all, since the failure to examine the Simanim after Shechitah invalidates the Shechitah even b'Di'eved! Since the Mishnah says that a Shechitah performed at night is valid b'Di'eved, it must be that the Shochet is assumed to examine the Simanim properly. Why, then, may he not perform Shechitah at night l'Chatchilah?
1. The Shitah Mekubetzes answers that because the person is in a situation in which he cannot examine the Simanim right away, there is a concern that the Shochet might forget to examine the Simanim in the morning. (The RASHASH also gives this answer to explain the words of Rashi.)
2. HA'GAON RAV Y. S. ELYASHIV shlit'a (as quoted in He'oros b'Maseches Chulin) explains that although the Shochet definitely will examine the Simanim when he can, there is a concern that his original Shechitah did not successfully cut a majority of the Simanim. It is possible that between the time he slaughtered the animal and the time he eventually examines the Simanim, the Simanim might tear further due to contact with a foreign object, and the Shochet will never know that he did not cut a majority of the Simanim.
Perhaps Rashi means that the Shechitah is valid only b'Di'eved because of the concern that the Shochet will examine the Simanim in the dark, and he will not perform a thorough examination of the Simanim. However, it seems that the Halachah requires that the Simanim be examined with a bright light, and thus if the Shochet examines the Simanim in the dark, the Shechitah still should be invalid (as if no examination was done at all). This is apparent from the DARCHEI TESHUVAH (YD 11:2), who quotes an opinion that one may be more lenient with regard to the amount of light required when checking the Simanim than with the Shechitah itself. While Shechitah needs to be done during daylight or with a bright torch, one may examine the Simanim by holding a candle next to the area of the cut Simanim. It is clear that this opinion maintains that lighting is also required for checking the Simanim. This is also implied by the wording of the SHULCHAN ARUCH (YD 25:1) who writes, "And if he did not see that a majority was cut, the animal is forbidden." The fact that this requires sight indicates that it must be done by some kind of light.
(b) The Shitah Mekubetzes quotes the TOSFOS CHITZONIYOS who explains that a person who slaughters at night tends to be very nervous that his hand might be cut by the knife. Due to this fear, he might do Shehiyah, a forbidden pause during Shechitah, or Derisah, slaughtering with a downward, chopping motion instead of a back-and-forth, sawing motion. This is also the opinion of the RASHBA.
There seems to be a practical difference between the explanations of Rashi and the Tosfos Chitzoniyos. According to Rashi, it is possible that one may perform Shechitah at night l'Chatchilah if he is certain that he can examine the Simanim immediately after the Shechitah (such as by going into a brightly-lit room nearby). According to the Tosfos Chitzoniyos, even if a bright light will be available immediately after the Shechitah in order for the person to examine the Simanim, the Shechitah is valid only b'Di'eved, because the concern that the person was nervous when he cut the animal is still present. However, the ARUCH HA'SHULCHAN (YD 11:1) rules that even according to the explanation of Rashi, there is a concern that the person will forget to go into the lighted area afterward to examine the Simanim. (Y. MONTROSE)
5) PERFORMING "SHECHITAH" ON A ROOF, OR INTO A CONTAINER
QUESTION: The Gemara quotes a Tosefta that permits one to perform Shechitah (l'Chatchilah) while on a roof, and while on the deck of a ship. Why would one have thought that such a Shechitah is prohibited, such that the Tosefta needs to permit it?
ANSWER: RASHI (DH Bein b'Rosh ha'Gag) explains that the Tosefta needs to permit performing Shechitah on a roof or on the deck of a ship because one might have thought that performing Shechitah on a rooftop or on a boat is prohibited, lest onlookers think that the Shochet is slaughtering the animal to a celestial being. The Mishnah later (41a) prohibits slaughtering an animal in a way that causes the blood to fall into the sea, or into a container, lest onlookers think that the Shochet is slaughtering the animal to a sea-god, or that he is collecting the blood in a container to offer it to an idol. Rashi explains that this prohibition does not apply when the Shochet slaughters the animal while on a boat. Even though he lets the blood fall into the sea, it is obvious that he is doing so in order to prevent soiling the boat, and not to serve any idols. (See, however, TOSFOS, who argues with Rashi and points out that the Gemara later (41b) says that one may not let the blood from the Shechitah fall into the sea even while one is traveling on a boat. Rather, one must let the blood fall on the boat, and from there it will flow into the sea.)
(b) Perhaps the reason why the Tosefta needs to permit slaughtering an animal on a rooftop or on the deck of a boat is that one might have prohibited such a Shechitah out of concern that the Shochet became nervous on the top of the roof and his trembling hand ruined the Shechitah, or that the rocking of the boat caused his hand to move and ruin the Shechitah. (M. KORNFELD)

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