Explanation #1 (Rashi): [We find that] one gives [a Bechor Ba'al Mum] to a Kohen only from a Ribuy.

Objection: According to his Perush, one can say so (we do not find another source in the Torah) about all Drashos!

Explanation #2 (Ri): It means that we do not find in the entire Torah like this. Chatas and Asham are to the Kohen when he offers them to the Mizbe'ach. If they became blemished, that the Mizbe'ach loses its share, also the Kohen loses;

However, Bechor, even if it is a Ba'al Mum, it is of the Kohen.

Support #1: Similarly, in Menachos (91b) regarding Nesachim "la'Keves ha'Echad" - this refers to the 11th [that left the pen that was called] Ma'aser;

We do not find in the entire Torah like this, that Tafel (what is secondary) is more severe than the Ikar (what is primary), i.e. that Ma'aser itself does not require Nesachim, and the 11th (which is Kodesh due to Ma'aser) requires Nesachim.

Implied question: Why don't we ask from it in Zevachim (48b) regarding what it says "we do not find Tafel more severe than the Ikar"?

Answer: It is because we could have answered that the 11th of Ma'aser is a Shelamim, like it answers about Mosar Pesach.

Support #2: And similarly in Shabbos (83b) "this is Heset of a Zav. We do not find [anything else] in the entire Torah that Tum'ah that moves something is Metamei." ("Zav" includes Nidah, Zavah and Yoledes; their Tum'ah is all the same.)

Reference: In Zevachim (57a), R. Yishmael answers that [the verse] means the meat of those Bechoros.

Inference: He means that it refers to Bechor Shor, Kesev v'Ez written above. It is a different answer [than here].

Question: This Tana (R. Yishmael) does not expound anything from the plural u'Vsaram, and in the Sugya there, above (56b) R. Yosi ha'Gelili expounds "it does not say Damo, rather, Damam. It does not say Chelbo, rather, Chelbam. This teaches that blood and Chelev of Bechor and Ma'aser must be put on the Mizbe'ach"!

Answer: This is an argument in Zevachim (37a), and R. Yishmael learns from "v'Dam Zevachecha Yishafech."

Explanation #1 (Rashi): It did not have a Mum.

Question: Why does it say "he is Reshai (allowed) to keep it for two or three years?" You are forced to say that he keeps it!

Poor Answer #1: "Reshai" means that he must, like in Erchin (28b), about Hekdesh Iluy (he was Macharim a Nedavah). He gives the amount that one would pay to bring this animal for an Olah, even though he is not Reshai, i.e. even though he is not obligated.

Answer #2: We could say that it says he is Reshai to keep it, i.e. he need not lock it in a cell [to starve to death], even though other Kodshim that one who one was Makdish or Macharim nowadays we say in Avodah Zarah (13a) that an animal Te'aker. I.e. he locks the door in front of it, and automatically it [starves and] dies.

However, it connotes that if he wanted to enter it in a cell, he may. Cases occur every day that they guard it until it gets a Mum.

Explanation #2: "Until it was Nir'eh to show to a Chacham" means that he did not encounter a Chacham after it got a Mum. He is not obligated to bring it to a far place where the Chacham is.

Explanation #1 (Rashi): [This is Hashavas Aveidah for the] Kohen, for sometimes one does not find a Kohen to give it to, and if he will slaughter it immediately, it will rot. Therefore, he may keep it 30 days after its year.

Explanation #2 (Tosfos' Rebbi): We discuss [a Bechor] in the Kohen's Reshus. He does not need the meat now. Chachamim gave him 30 days.

Distinction: However, a Yisrael always waits until he finds a Kohen.

Pesak (Tosfos' Rebbi): Even though we say in Kesuvos (57a) that the Halachah follows decrees of R. Meir, this here is called below a fine that R. Meir fines, and the She'altos of Rav Achai explains that the Halachah follows him only in his decrees, but not in a fine;

They (my Rebbi and the She'altos; alternatively, the Gemara) ruled that the Halachah does not follow him in the case of [one who married] a woman pregnant with, or nursing, another's man's baby. R. Meir says that he divorces her, and may never remarry her. The Sugya in Yevamos (37a) is unlike R. Meir.

Similarly, our Sugya is like R. Yehudah, for according to R. Meir we fine all of them due to [Mumim] that change.

And below, that it says "let us say that our Stam Mishnah is unlike R. Meir", it answers that perhaps it discusses Dukin in the eye, and it is like everyone. This is the truth.

Consequence: Due to this, my Rebbi rules unlike R. Meir, who fines a document with Ribis, that he does not collect the principal, and not the Ribis (Bava Metzi'a 72a).

Explanation #1 (Rashi): This is money in Safek. Perhaps the Chacham will permit it based on a Mum, and perhaps he will not permit it.

Remark: [The reason he pays half] is not because it is like Sumchus [who says that when there is a Safek about money, we divide]. Rather, it is a mere enactment of Chachamim.

Implied question: We discuss a Ba'al Mum, even if it is known that an expert would permit it!

Answer #1: In any case it is considered somewhat of a Safek, for perhaps an expert would not consent to inspect it.

Answer #2: We do not distinguish between one Mum and another.

Answer #3: If this Beraisa discussed only Dukin in the eye, it would be better, for also now we hold like R. Yehudah, like I explained (28a DH R. Meir), and he holds that it is buried only due to Dukin in the eye.

Explanation #2: The reason he pays [only] half is because Chachamim estimated that it is not worth more as long as it is in Safek, for it was not yet permitted.

Support: Also Terumah, we find that it is worth only half as much as Chulin, like we say in Kesuvos (58a) "wherever it mentions [a Kohen giving to his wife] Terumah, he gives to her twice as much as if he gave Chulin."

Disclaimer: It is not truly like Terumah, which is forbidden to Zarim, and Asur [to eat] b'Tum'ah, but a Bechor with its Mum is totally permitted, like Tzvi va'Ayal.

Explanation: Chachamim were stringent on [people who raise small animals], to raise them only in forests outside settled areas, and there is great toil, and it is worth only a quarter, i.e. half less than (i.e. of) a big animal.

Remark: Also Rashi explained so "due to the toil of raising it", but he was not meticulous to resolve the expression "decree". (Tosfos explains that the decree was that one may not raise them in settled areas.)

Reference: In Sanhedrin (6a) we ask this against R. Avahu, who says that if two [judges] judged, their verdict is invalid.

Question: What is [the Makshan's] source that it discusses a lone [judge]?

Suggestion: It is because it taught "he judged" in the singular.

Rejection: In Chulin (44b) it taught "he judged" in the singular, and it does not discuss an individual, like it taught "and all of them may buy [what they ruled about]"!

Note: I do not understand Tosfos' attempted rejection. It says there "if a judge ruled a case, vindicated or obligated, was Metamei or Metaher, forbade or permitted, and similarly witnesses who testified - all of them may buy it." Even if it discussed a lone Chacham who ruled, it needed to teach "all of them" due to the different cases - monetary, Tum'ah and Taharah, Isur v'Heter, and witnesses!

Answer (defense of Suggestion): There it taught [the plural] similar to witnesses, but our entire Mishnah discusses an individual;

Source: The Seifa taught "and if he was an expert [appointed by] Beis Din... and a case occurred with R. Tarfon..." and also the Reisha "one who is not an expert, and saw a Bechor..."

Question #1: Why didn't he infer here from the Reisha (28a) "one who is not an expert, and saw a Bechor, and it was slaughtered based on his mouth, it is buried and he pays from his house (money)"?

No matter what you will say, it is like R. Meir, who judges (obligates for) Dina d'Garmi (causing damage. It is more direct and more sure to result in damage than Gerama.) We cannot establish it when he gave the property [to the other party, or in this case, he slaughtered] with his [own] hand, for it taught "it was slaughtered based on his mouth"!

Question #2: In Bava Kama (100a) we do not find a Mishnah in which R. Meir obligates for Dina d'Garmi, only from a Beraisa of a wall in a vineyard. (It was breached, and the owner did not fix it, and it forbade his neighbor's grain. R. Meir obligates him to pay.) It should have brought the [Reisha] here!

Question #3: And in Bava Kama (117b) regarding one who showed [another's] property [to the kingdom, the Gemara] thought to obligate him based on our Mishnah of one who judged, and rejected this. Why didn't it bring from this (Reisha)? (Merumei Sadeh - the Poskim and Tosfos (Bava Kama 5a DH Leme'utei) obligate a Moser according to everyone. They similarly hold that all obligate here, even those who exempt Garmi, for there was another Isur (Shechitas Bechor Tam). Sefas Emes - all agree that we fine one who slaughtered and did not show that the Mum afterwards; for Dukin in the eye, showing afterwards does not help. R. Meir decrees all Mumim due to Dukin. This does not depend on Garmi.)