Reference: In Bava Basra (102a), the Gemara asks that he should check 22 Amos, for [Mesim at opposite ends of] two caves. The length [of the two caves is in all] 16 Amos, and Chatzer ha'Kever (which is between the caves) is six according to R. Shimon and Rabanan;

We answer that [our Mishnah says 20 Amos, for it discusses] Nefalim. It is common that when one of the caves is big, the other is for miscarriages. Therefore, it suffices for the other to be four by six.

There, some establish the Mishnah here like Rabanan, and say that the inside of [each] cave is four by six (unlike R. Shimon, who says that it is four by eight);

The Gemara asks that if so, he should check only 18, and answers that he checked the first cave on the diagonal, in order to check well. Since he bent to the side, this takes another two Amos.

Explanation #1 (Ri): If it was known, he does not move it, like we say in Sanhedrin (47b) "a found grave, one may move it. A known grave, one may not move it."

Implied question: There, we say that if he moved it, its place is Tahor. Here it connotes that it has Tefusah (one must take also three fingers depth of virgin soil, or earth that could be from the Mes)!

Answer (Ri): There, we do not discuss Tefusah. Tefusah is in the direction of going deeper into the ground. However, there it discusses Tum'ah mid'Rabanan. Mid'Rabanan, we are Metamei outside the entire grave in four directions.

Explanation #2 (Rashbam): "This excludes one that was known" refers to what it says below, "one that was known, and two that were found now."

Objection: If so, there was no need to say "one who finds", for the same applies to all three that were known, that they have [the law of] a burial site!

Note: I.e. the law of a burial site applies whether all three were known, or all three were found. We exclude only when one or two were known, and the other two or one were found. We do not exclude known graves any more than found ones! Presumably, the Rashbam's text was like Hagahos ha'Gra; the law of a burial site is only when all three were found.

Explanation: This is like we say below, that a deficient Mes does not have the law of Tefusah, and not the law of a burial site.

Citation of Gemara: A deficient Mes does not have the law of a burial site.

Question: It is difficult to understand why!

Answer: Perhaps it is a tradition from Moshe from Sinai.

Explanation #1 (Rashbam): This is a tradition from Moshe from Sinai.

Explanation #2 (Ri): There is a reason for it. We should not say that it is a burial site, and it was a cemetery, because three Mesim were buried there, since one was known initially;

If it is true that [the ones who buried them there] did not intent to move them, and they were buried to remain there, just like the one was known to us, the ones with him would be known to us!

The law of a burial site was taught only when three were known, or three were found now.

Explanation #1: [He takes chips] of a marble coffin that was crushed. (Since we say that there is Rekev, we must say that it was a marble coffin.) Some say that "Kesasos" are like Kozezos Adamah (clumps of earth).

"He discards the Vadai" means what is definitely not from the Mes. He leaves what is Safek, i.e. what he is unsure whether or not it is from the Mes. He leaves it in a hidden place, so people who engage in Taharos will not become Tamei through it.

"The rest" is what is clear to him that it is from the Mes.

They join with the majority of the stature or the majority of the number [of bones], and to a Rova, i.e. quarter Kav of bones, to have Tum'as Ohel.

Explanation #2: Some say that "Kesasos" is like Koses wine (it soured), i.e. vinegar or spices that they put in the coffin.

Objection: If so, there is no Rekev, for it is Galgalin, just like a Mes buried in a wood coffin. Even hair destined to be cut, we asked about it above (51a) whether it is Galgalin!

Explanation #3: "Kesasos" refers to something worn out, like "v'Es Piryah Yekoses."

Inference: R. Eliezer bar Tzadok holds that one need not take Tefusah. He need not dig in virgin soil. He needs to take only what is Vadai from the Mes, and what is Safek.

Explanation: He already moved [the first two] before he knew that there are three. He may move even the third where he wants, for we do not establish a burial site through one.

Question: This is difficult.

Answer: Perhaps this is a tradition from Sinai, and all this is part of the Halachah.

The Gemara suggested that we should establish it to be a burial site. Reish Lakish answered that they found an excuse and were Metaher all of Eretz Yisrael. We should not establish Tum'ah and be stringent.

Explanation: We establish him on his Chazakah;

In Maseches Nega'im (5:4) it explains that two came to a Kohen. One had a Baheres (appearance of Tzara'as) the size of a bean, and the other had a Baheres the size of a coin (a Sela);

At the end of a week, each is the size of a bean, and he does not know which spread. [Each] is Tahor.

Citation of Gemara: Once he was declared Tamei (Muchlat).

Citation (Nega'im 5:4 - Mishnah): Two came to a Kohen. One had [a Baheres] the size of a coin, and the other had the size of a bean. At the end of a week, each is more than the size of a coin. They are Tamei [Muchlat];

Citation (cont.): At the end of a week, each is the size of a coin. He does not know which dulled (the spreading went away, and is no bigger than it was at the end of the first week). Both are Tamei, until it will be the size of a bean [or less] on both of them, for we establish each in Chezkas Tum'ah.

Question: If he was Metamei, this is like the first Tana! (What do they argue about?)

Answer (Rabbeinu Yehudah of Korvil): Perhaps Keihah and he was Metamei. He comes to argue with the first Tana, for the first Tana is Metamei due to Safek. R. Yehoshua says that he is a Vadai Metzora [Muchlat];

The Gemara answers that he was Keihah and totally Metaher, for it says "Letaharo Oh Letam'o" - since the verse began with Taharah first, [the Torah said that] a Metzora is totally Tahor or totally Tamei. (Keren Orah - all expound that there is no Tum'as Metzora mi'Safek. Since the first Tana is Metamei Vadai, R. Yehoshua must be Metaher.)

Note: The words of Tosfos connote that because the Torah began with Taharah, there is no Tum'as Safek. I do not understand this. Arzei ha'Levanon suggests that "because the Torah began with Taharah" explains why R. Yehoshua is Metaher. (However, all agree that "Letaharo Oh Letam'o" teaches that there is only Taharah Vadai and Tum'ah Vadai.)

Explanation: E.g. regarding the first two sightings we check him, regarding eating, drinking, carrying, and jumping.

"Seeing" refers to seeing a man and woman having relations.

Support: In Zavim (2:2), R. Yehudah argues, and says that even if he saw animals, Chayos or birds mating [this is called seeing, for] he will have thoughts.

Citation of Gemara: Once he became Tamei.

Explanation: E.g. we do not check him on the third sighting according to Rabanan in Nidah (35a), which obligates him a Korban, or on the fourth sighting according to R. Eliezer, to be Soser [clean days that he counted];

This is because '"mi'Besaro", and not due to Ones' refers only to the first two sightings according to Rabanan, or [even] the third, according to R. Eliezer.

Explanation: Why doesn't R. Eliezer hold like the Drashah we said? Rather, they argue about expounding "Es";

R. Eliezer expounds "ha'Zav" to teach one sighting. "Es" teaches a second. "Zovo" is a third. Regarding the fourth, ["la'Zachar vela'Nekevah"] equates him (a Zav) to a female (Zavah). In Nidah (35a), the Gemara explains more.