1) "BITUL" IN THE CASE OF A "HEFSED MU'AT"
QUESTION: In the beginning of the Beraisa (81b), the Tana Kama and Rebbi Yehudah disagree about whether a Tamei piece of meat ("Chatichah") of a Korban Chatas which becomes mixed with a hundred Tahor pieces is Batel. In the end of the Beraisa, everyone agrees that if a Tahor piece of meat of a Korban Chatas becomes mixed with a hundred pieces of Chulin, it is not Batel. The Gemara explains the Beraisa according to both the opinion of Rebbi Yochanan and the opinion of Reish Lakish.
RASHI (81b, DH Divrei, and 82a, ul'Reish Lakish) explains that according to Rebbi Yochanan, the Beraisa discusses whole pieces which are considered "Kol she'Darko Limanos" (see previous Insight). The Beraisa rules that an object which is "Kol she'Darko Limanos" is Batel because it does not have the status of a "Davar sheb'Minyan." In the second case of the Beraisa, the piece of Chatas is not Batel because it is a "Hefsed Mu'at" -- it involves only a minimal loss since one can sell the entire mixture to a Kohen (who may eat both meat of Chatas and Chulin).
The Gemara asks that according to Reish Lakish who maintains that the Tana'im in the Beraisa maintain that an object which is "Kol she'Darko Limanos" is considered a "Davar sheb'Minyan" and is not Batel, the Beraisa must be discussing disintegrated pieces which are no longer a "Davar sheb'Minyan." However, if the Beraisa is discussing disintegrated pieces, why in the second case of the Beraisa is the Tahor piece that becomes mixed with Chulin not Batel?
What is the Gemara's question? The Gemara just said that according to Rebbi Yochanan, the piece of Chatas is not Batel in Chulin (even though it is not a "Davar sheb'Minyan") because it is a Hefsed Mu'at, a minimal loss. Similarly, according to Reish Lakish the reason the piece of Chatas that becomes mixed with Chulin is not Batel is that it is a Hefsed Mu'at! The fact that the piece is disintegrated and is no longer a "Davar sheb'Minyan" is not relevant; Hefsed Mu'at provides a different reason for why it is not Batel.
ANSWER:
(a) RASHI (DH Tehorah, DH Tehoros) implies that the Gemara understands that Reish Lakish and Rebbi Yochanan argue about this very point: should the law in the case of Chatas mixed with Chulin be more stringent (because it is only a Hefsed Mu'at) or not? According to Reish Lakish, the Gemara (beginning of 82a) proves that when a piece of Chatas becomes mixed with Chulin, and both the Chatas and the Chulin are Tahor, the law is not more stringent but rather more lenient, since the Chatas in the mixture may be eaten by Kohanim. In contrast, in the first case of the Beraisa in which a Tamei piece of Chatas becomes mixed with Tahor pieces, even Kohanim may not eat the mixture and thus the law is more stringent. For this reason, the Gemara assumes that Reish Lakish does not explain that the law is more stringent in the Beraisa's second case because it involves a "Hefsed Mu'at." Rather, the Gemara suggests other reasons for the more stringent ruling in the second case (for example, the Seifa involves an Isur d'Oraisa while the Reisha involves only Tum'ah mid'Rabanan).
However, this explanation is problematic. As Rashi himself asks, if the law is more stringent when the mixture may be eaten (by Kohanim) without Bitul, why does Rebbi Yosi allow an Igul of Terumah to become Batel? Even if it is not Batel, a Kohen may eat the mixture! Rashi answers that the law is not stringent in the case of an Igul because the requirement to separate Terumah from fruits is only mid'Rabanan. Rashi's answer is problematic, however, because throughout the Sugya the Gemara assumes that Terumah of fruits is just as stringent as Terumah of grains; if the latter is d'Oraisa, the former will be treated stringently as well. This was the very basis for Reish Lakish's proof (from the case of the Igul that is Batel) that the obligation to separate all Terumah nowadays is only mid'Rabanan. (TOSFOS YESHANIM 81b, ARUCH LA'NER ibid.)
Moreover, according to Rashi the logical reasoning of Rebbi Yochanan and that of Reish Lakish are diametrically opposed. Rebbi Yochanan says that the law must be more stringent with a mixture of Terumah in Chulin, while Reish Lakish says that the law must be more lenient. (MAHADURA BASRA)
(b) TOSFOS (81b, DH Divrei) suggests another explanation for the difference between the Reisha and the Seifa of the Beraisa.
According to Tosfos, Rebbi Yochanan understands that the reason for the more stringent ruling in the Seifa is that a cut of meat is a "Davar Chashuv." While it might not be an object which is "Es she'Darko," it nevertheless is important in its own right since it is a "Chatichah ha'Re'uyah l'Hiskabed," a portion fit to be served to guests as a display of honor to them. Such an item does not become Batel (Chulin 97b).
Why, then, is the cut of Chatas meat Batel in the Beraisa's first case, in which a Tamei piece of Chatas becomes mixed with Tahor pieces of Chatas? Tosfos explains that the meat of a Chatas cannot be called "Re'uyah l'Hiskabed," because Kohanim do not give meat of Korbanos to their guests as a display of honor. Rather, the meat of Korbanos is divided equally among the Kohanim who serve in the Beis ha'Mikdash; it is not served to guests. Since the meat is not considered fit to be served to guests, it can become Batel. In the case of the Seifa of the Beraisa, in which a Tahor piece of Chatas becomes mixed with Chulin, if the laws of Bitul would be applied the meat would not be considered meat of a Korban and would be fit to be served to guests. Therefore, the meat is considered a "Chatichah ha'Re'uyah l'Hiskabed" and cannot become Batel.
Tosfos asks, however, that according to this explanation it should make no difference whether Chatas Tahor or Chatas Tamei becomes mixed with Chulin. In both cases the piece of Chatas should not become Batel. Why, then, does the Seifa of the Beraisa mention specifically Chatas Tahor which falls into Chulin? (According to Rashi, the reason why the Beraisa mentions Chatas Tahor is clear: it is only when Kohanim are able to eat the meat that the Chatas is not Batel (according to Rebbi Yochanan) or is more easily Batel (according to Reish Lakish). See, however, RASHASH and PORAS YOSEF on the words of Rashi here. See also BA'AL HA'ME'OR.)
(c) Other Rishonim (see BA'AL HA'ME'OR and RAMBAN in Milchamos) have a different Girsa in the Gemara, in which the Gemara does not preface its question with the words, "And according to Reish Lakish...." They explain that according to both Rebbi Yochanan and Reish Lakish, the Gemara has not yet found an explanation for the difference between the Reisha and the Seifa.
(A third Girsa is recorded by the GE'ONIM, as cited by the Rashba. According to that Girsa, the Gemara seeks the difference between the Reisha and Seifa only according to Rebbi Yochanan. According to the way the Ramban (in Milchamos) explains the Gemara, the Gemara indeed cannot explain the difference between the Reisha and Seifa according to Reish Lakish, because he maintains that a Gezeirah should have been enacted that a Tamei piece mixed with Tahor pieces is not Batel, just as a piece of Chatas in Chulin is not Batel. Hence, the Gemara seeks to explain the difference only according to Rebbi Yochanan.)
2) "BITUL" MID'ORAISA OF TERUMAH
QUESTION: The Gemara cites a Beraisa which discusses a case of two baskets. One contains Chulin and one contains Terumah. Two dishes, one of Chulin and one of Terumah, fell into the two baskets, and it is not known which dish fell into which basket. One may assume that the Terumah fell into the basket of Terumah, and that the Chulin fell into the basket of Chulin. The Gemara explains that one may be lenient in this case because even if the Terumah fell into the basket of Chulin, the mixture would be prohibited only mid'Rabanan.
Why would Terumah mixed with Chulin be prohibited only mid'Rabanan? Reish Lakish explains that mid'Oraisa the Terumah is Batel b'Rov, since the basket of Chulin contains more Chulin than the amount of Terumah that might have fallen into it.
However, the Halachah is that Terumah is Batel only when there are one hundred parts more Chulin than Terumah. The Sifri derives from the verse, "Es Mikdesho Mimeinu" (Bamidbar 18:29), that if the amount that one consecrated as Terumas Ma'aser falls into the original produce from which it was removed, the entire mixture becomes forbidden because the Terumah constitutes one part out of a hundred (that is, the mixture is one part Terumah and 99 parts Chulin). This Derashah teaches that when Terumah falls into one hundred parts (one part Terumah and one hundred parts Chulin), it is Batel. (See TOSFOS 73a, DH Mah, and RASHI to Chulin 99a, DH she'Nisbashlu.)
Why, then, does the Gemara here say that as long as there is more Chulin in the basket, the Terumah is Batel mid'Oraisa? Terumah is Batel mid'Oraisa only when there is at least one hundred parts more Chulin in the mixture.
(When the Gemara says that there is a majority of Chulin in the mixture, it cannot mean that there is one hundred times more Chulin than Terumah, because if this is the Gemara's intention there would be no question that the Terumah is Batel, and the Beraisa would not need the Heter of "we say that the Terumah dish fell into the Terumah basket." Even if the Terumah clearly fell into the basket of Chulin (and there was no basket of Terumah present), the basket of Chulin would be permitted because the Terumah is Batel in one hundred parts of Chulin.)
ANSWERS:
(a) TOSFOS (73a, DH Mah she'Ein) proves from the Gemara here that the Sifri's teaching is only an "Asmachta," and the requirement for one hundred parts more Chulin is only mid'Rabanan. Mid'Oraisa, even Terumah is Batel b'Rov. This seems to be the understanding of all of the other Rishonim as well.
(b) The OR SAME'ACH (Hilchos Ma'achalos Asuros 15:16) suggests a novel approach. Perhaps the Sifri indeed teaches mid'Oraisa, Terumah is not Batel b'Rov. Why, then, does Reish Lakish say that there must be more Chulin than Terumah, if the Terumah still would not be Batel mid'Oraisa until there is a hundred times more Chulin than Terumah?
The Or Same'ach explains based on the RAMBAM (Hilchos Shechitah 5:3) that an Isur which is written explicitly in the Torah is treated with greater gravity than an Isur which is not written explicitly in the Torah (but is still d'Oraisa; see also RAN to Nedarim 8a, DH Ha Ka Mashma Lan, and SHITAH MEKUBETZES to Kesuvos 40a, DH Hachi Nami). The prohibition against eating a mixture of Terumah in a majority of Chulin (but less than one hundred times more Chulin) is not written explicitly in the Torah, while the prohibition against eating a mixture which is mostly Terumah is explicitly forbidden by the Torah. Therefore, Reish Lakish is justified in saying that since there is a majority of Chulin, mid'Oraisa the mixture may be treated leniently.