(Abaye): If Reuven was Metamei (someone else's) Taharos and he died, his son is exempt.

Question: What is the reason?

Answer: Letter of the law, Hezek she'Eino Nikar (damage that is not physically perceivable) is not considered damage. Chachamim fined that one must pay for it (to deter people from doing such damage). They fined only the damager, but not his son.

(Mishnah): A case occurred in which a Nochri official asked about an old sheep with very long wool. They told him that it is a Bechor, which may not be slaughtered without a Mum. The Nochri pierced its ear. Chachamim permitted (slaughtering) it.

The Nochri saw this, and went around piercing ears of Bechoros. Chachamim forbade them (until another Mum came).

A case occurred in which children were playing. They tied tails of lambs together. This caused one to come off. The lamb was a Bechor, and Chachamim permitted it.

The children saw this, and went around tying tails of Bechoros together. Chachamim forbade slaughtering them.

Version #1 (Our text): The general rule is, a Mum made l'Daito (in accordance with the owner's desire) does not permit Shechitah. A Mum Lo l'Daito permits.

Version #2 (Rashi): The general rule is, any Mum made l'Da'as (with intent to permit the animal) does not permit Shechitah. A Mum Lo l'Da'as permits. (end of Version #2)

(Gemara): The Mishnah must teach both cases:

Had it taught only about the case of the Nochri, one might have thought that there the Bechor is permitted, for he will not teach Yisraelim to do so, but this is a concern with children (so we must forbid it);

Had it taught only about the case of the children, one might have thought that there the Bechor is permitted, for people will not confuse this with a Mum made by an adult, but they would confuse a Nochri with a Yisrael.

(Rav Chisda): The Bechor is permitted only if they told the Nochri "(it may not be slaughtered) unless it has a Mum";

If they told the Nochri "unless a Mum is made in it," this is like telling him to make a Mum, so it is forbidden.

Objection (Rava): In either case, the Nochri did not know that it will be permitted if he makes a Mum!

Rather, in either case it is permitted.

(Mishnah): The general rule is, any Mum made l'Daito (does not permit).

Question: What does this come to include?

Answer: It includes a Mum that was (not directly made, but only) caused.

(Mishnah): Any Mum made Lo l'Daito (permits).

This includes Mesi'ach l'Fi Tumo. (Rashi - a Yisrael mentioned that he cannot slaughter the Bechor until it gets a Mum, without intent that a Nochri listening will make a Mum. Sefas Emes - a Nochri mentioned that he blemished a Bechor without intent to permit it.)

(Mishnah): If a Bechor chased Reuven (to gore him) and Reuven kicked it (and made a Mum), it may be slaughtered due to this Mum.

Version #1 (Rav Papa): This is only if Reuven kicked it while it was chasing him. If he kicked it after it stopped chasing him, it may not be slaughtered (due to this Mum).

Question: This is obvious!

Answer: One might have thought that he kicked due to the pain it caused him, and not with intent to make a Mum (and it should be permitted). Rav Papa teaches that this is not so.

Version #2 (Rav Papa): Not only if Reuven kicked it while it was chasing him, rather, even if he kicked it after it stopped chasing him, it may be slaughtered.

Question: What is the reason?

Answer: He kicked it due to the pain it caused him.

(Rav Yehudah): One may blemish a Bechor before it leaves the womb (for it is not yet Kodesh).

Version #1 (Rava): One may blemish the ear of a goat (before the head comes out, which completes birth), or the lip of a lamb (but not its ear, for the ear is small, and it does not come out until the head is out - Rashi; Tosfos - we are concerned lest most of the head already came out and went back in).

Version #2 (Rava): One may blemish even the ear of a lamb. If the head comes out sideways, the ear precedes (most of) the head.

(Rava): If a blemish (in the mouth) cannot be seen when the animal eats, but can be seen when it "talks," it is a Mum.

Question: We already learn this from a Mishnah!

(Mishnah): If the outer Chutin (Rashi - gums; R. Gershom - teeth) are chipped or cracked, or if the inner Chutin are uprooted (it is a Mum).

Suggestion: Uprooting of the inner Chutin is a Mum because it can be seen when it "talks."

Answer (Rav Papa): Indeed, Rava explains the Mishnah. Uprooting of the inner Chutin is a Mum because it can be seen when it "talks."

(Mishnah): Ro'ei Yisrael (shepherds) are believed about Mumim that could have been made by a person. (They are believed to say that the Mumim occurred by themselves.) Ro'ei Kohanim are not believed;

R. Shimon ben Gamliel says, he is believed about another's Bechor, but not about his own.

R. Meir says, one who is suspected about a matter cannot testify about or judge it.

(Gemara - R. Yochanan or R. Elazar): (The first Tana teaches that) a Yisrael (shepherd) working for a Kohen is believed. We are not concerned lest he lie (to say that a Mum occurred by itself), hoping that the Kohen will slaughter it and give him some to eat;

A Kohen working for a Yisrael is not believed. He thinks 'since I work for him, he will give the Bechor to me when it gets a Mum.' Perhaps the Kohen will lie.

A Kohen working for a Kohen is not believed. We are concerned for Gomlim. (Perhaps he will lie to permit the Bechor for his boss, expecting that when he himself will have a Bechor, his boss will lie for him to return the favor.)

R. Shimon ben Gamliel holds that a Kohen is believed about another's Bechor, but not about his own;

R. Meir holds that one who is suspected about a matter cannot testify about or judge it.

(The other of R. Yochanan and R. Elazar): (The first Tana teaches that) a Kohen (shepherd) working for a Yisrael is believed. He will not lie, for he does not expect to receive the Bechor. He assumes that his boss will give the Bechor to a Kohen Chacham. (Normally, shepherds are not Chachamim);

A Yisrael working for a Kohen is not believed. Perhaps he will lie, (for he hopes) to receive some meat;

All the more so, a Kohen working for a Kohen is not believed. He might lie to receive some meat, and we are also concerned for Gomlim.

R. Shimon ben Gamliel holds that a Kohen is believed about another's Bechor, but not about his own;

R. Meir holds that one who is suspected about a matter cannot testify about or judge it.

Question: According to the latter explanation, we understand the argument of R. Meir and the first Tana. The first Tana trusts a Kohen working for a Yisrael, and R. Meir never trusts a Kohen;

However, according to the first explanation, also the first Tana never trusts a Kohen. What do R. Meir and the first Tana argue about?

Answer: They argue about R. Yehoshua ben Kafusai's law:

(Beraisa - R. Yehoshua ben Kafusai): To permit a Bechor in a Kohen's house, two witnesses from outside (his household) are required (to say that the Mum came by itself);

R. Shimon ben Gamliel says, even his son or daughter can testify;

R. Yosi says, even 10 people from his household cannot permit it. (Rashi - this is not exactly like R. Yehoshua. R. Yosi holds that even one stranger can permit it.)

Question: Like which Tana is the following teaching?

(Rav Chisda): If a Safek Bechor was born in a Yisrael's house, two witnesses from outside are required.

Answer: It is like R. Yehoshua.

(Rav Nachman): A Yisrael can testify about a Safek Bechor in his house.

Support (Rav Nachman, for himself): If even a Yisrael were not believed about his own, according to R. Meir (he would not be believed about anyone's, so) no one would be believed to permit Ma'aser Behemah!

Objection: No one is suspected about Ma'aser, for one may blemish his entire herd before taking Ma'aser! (This is permitted, for the animals are still Chulin.)

Correction: Rather, if a Yisrael were not believed about his own, according to R. Meir, no one would be believed to permit Safek Bechor!

Suggestion: Perhaps, indeed, he holds that it cannot be permitted!

Rejection (Mishnah - R. Yosi): Whenever the Kohen received Chalipin of (something in exchange for) an animal, the animal is exempt from Matanos (foreleg, jaw and stomach. E.g. we are unsure which of two animals is a Bechor, so the Kohen took one of them);

R. Meir obligates giving Matanos. (It follows that the animal may be eaten.)

Conclusion: We must say that a Yisrael is believed about his own Bechor. Only Kohanim are suspected about Mumim.

(Rav Nachman): The Halachah follows R. Shimon ben Gamliel.

(Rava): The Halachah follows R. Yosi.

Question: Rava taught that if the owner was outside (his house) with witnesses, and the animal entered the house Tam and came out blemished, the witnesses may testify to permit it! (We do not suspect that his household blemished it!)

Answer: Rava means that if the owner's entire household was outside, we are not concerned.

Question: If so, what is the Chidush?

Answer: One might have thought that we are concerned lest people suspect (that the owners caused that it will become blemished, e.g. they dug a pit in the house. Alternatively, there was a shepherd in the house. One might have thought that people will suspect him.) Rava teaches that this is not so.

The Halachah follows R. Shimon ben Gamliel.

A Kohen's sons and daughters are believed (to testify about their father's Bechor), but his wife is not.

Question: What is the reason?

Answer: A woman is considered like her husband.

Question (Rav Papa): R. Meir says that one who is suspected about a matter cannot testify about or judge it, and that one who is suspected about one matter is suspected about everything in Torah;

Since Kohanim are suspected about Mumim, they should be disqualified from judging. However, it says "v'Al Pihem Yihyeh Kol Riv v'Chol Naga"!

Answer (Abaye): R. Meir suspects a Kohen concerning Mumim. He is not established to lie about it. (Only one who is Muchzak to lie about a matter is suspected about everything.)