Explanation: We should resolve that since the Mishnah taught the spine and skull intact, and presumably they have a quarter Kav of bones...

Inference: For broken and separated bones that have a quarter Kav, and they come from the spine and skull, he does not shave.

We ask that he himself, i.e. Rava, said that we need this only for a spine and skull without a quarter Kav of bones!

Rather, Rava himself holds that there is a spine and skull without a quarter Kav of bones. Really, I can say that even a quarter Kav of bones that comes from the spine and skull, a Nazir shaves;

Our Mishnah taught a spine and skull, which connotes that they are complete. It needs to teach that even if there is not a quarter Kav, a Nazir shaves.

Observation: It was not explained where Rava taught this. The text in some Seforim above (50a) says "Rava said, we need this only for a spine and skull without a quarter Kav of bones" based on the Sugya here.

Rejection: Above, I explained why this text cannot be correct.

Question: So it is written in all Seforim. It was not explained what he wants to say. This is difficult.

Answer #1: If I did not fear my Rebbeyim, I would say that there is an omission in Seforim. In the [correct] text, before the question that Rava said, "we need this only...", it says "Mar Ukva said, here we discuss a spine and skull without a quarter Kav."

Explanation: Mar Ukva comes to reject the answer that Rava gave, because he holds that Rava held that a Stam spine and skull have a quarter Kav. Mar Ukva rejects this. We discuss a spine and skull without a quarter Kav.

The Gemara asks "does Rava disagree with this reasoning, that it is possible that a spine and skull do not have a quarter Kav? Rava said "we need this only..."!

The Gemara answers that after he heard from Mar Ukva, the answer that Mar Ukva gave here, that we discuss a spine without a quarter Kav [Rava agreed with him].

Support: Rashi corrected the text in Zevachim (21b) like this. The answer was written in Seforim, and the question was missing from Seforim, and Rashi corrected [the text, and added] the question, regarding the Sugya of washing the hands.

Also in our Sugya, there is the question without the answer, we should correct [it and add] the answer.

Elsewhere we find that Rava was the days of Mar Ukva. All this is from R. Peretz.

Answer #2 (R. Yakov of Kinun): With difficulty, we can resolve the text of Seforim "after he heard from R. Akiva." It means as follows:

Rava himself said "this is needed only..." I.e. what was Rava's Havah Amina to bring [a proof] from our Mishnah? He himself establishes it to discuss a spine and skull without a quarter Kav of bones!

We answer that after he heard from R. Akiva, Rava did not say so about our Mishnah, rather, about the Mishnah in Ohalos (2:6) that lists a quarter Kav of bones from two Mesim, and a spine and skull from two Mesim;

Regarding that [Mishnah] he needed to answer so. However, before he heard from R. Akiva, he held that there is no spine and skull without a quarter Kav of bones;

This is why Rava properly brought [a proof] from our Mishnah, for he had not yet heard from R. Akiva.

Explanation: Since Shamai requires only a bone from the spine, this implies that for Rabanan, who argue with him, the Shi'ur of a quarter Kav of bones from the spine suffices;

This is like the Reisha teaches, that a quarter Kav has Tum'as Ohel when it comes from the primary part of the body. And when a quarter Kav comes from the spine, it even obligates a Nazir to shave;

It is unreasonable to say that they have such an extreme argument, that according to Rabanan we require a half-Kav, and according to Shamai, one bone suffices!

We reject this. Shamai is different, for he is stringent. However, Rabanan require half a Kav of bones, even from the spine.

Explanation (cont.): [Now] we say that we should resolve oppositely, that Rabanan require half a Kav. Since Shamai, who is stringent, requires only one bone, this connotes that Rabanan require the Shi'ur of Beis Hillel, i.e. half a Kav.

If they required only a quarter Kav, they should have specified their stringency, just like Shamai specified his stringency.

We reject this. Perhaps they argue only about one bone. Rabanan hold that it is not Metamei b'Ohel, but a quarter Kav is Metamei. They were not concerned to specify their opinion.

Explanation: [A half Kav of bones and a half Log of blood is Metamei for everything,] even for a Nazir, like our Mishnah teaches. A quarter Kav of bones and a Revi'is of bones [is Metamei] for Terumah and Kodshim. One who towers over them is Tamei, like our Mishnah of Ohalos (2:1,2);

However, it is not Tamei for Nazir and one who offers Pesach. This is a tradition [from Moshe from Sinai].

They hold like our Mishnah that a Nazir is not Megale'ach for it. They hold also like our Mishnah in Ohalos, which teaches there that it is Tamei elsewhere, for Terumah and Kodshim;

Inference: The latter Beis Din holds like the Tana of our Mishnah, and like the Tana of Ohalos.

Explanation #1: Some say that "a third Hachra'ah" refers to Talmidim of the latter Beis Din. They were Talmidim of the earlier Zekenim. The Gemara asks that a third Hachra'ah does not determine that we follow it. (This is like Rashash, that this last word is "Basrah." Others says that it is Basraihu (follow them), or b'Travaihu (it does not override both previous opinions).

Our Mishnah here and our Mishnah there in Ohalos hold like the latter Beis Din. This is the Halachah, because they are a Machri'a.

Explanation #2: Some say [that "a third Hachra'ah" refers to] a third opinion. We asks that a third Hachra'ah does not determine, because it is its own reason, because the first [opinions] did not reveal their opinion that it is proper to distinguish between (1) a Nazir and one who offers Pesach, and (2) Terumah and Kodshim.

We answer that R. Yakov bar Idi said that they said it in the name of Chagai, Zecharyah and Malachi. Therefore, it is proper to rely on what the latter Beis Din received, and fix the Halachah like them.

Implied question: [The Seifa] explicitly taught a bone the size of a barley seed, for touching or moving it. This implies [that he does] not [shave] for its Ohel!

Answer: [The Tana] teaches [concisely] and later explains.

Explanation: "For these" in the Seifa exclude Even ha'Sechachos, i.e. a rock that towers above the ground, and there are two or three rocks jutting out from a fence, and Tum'ah is under one of them. Someone passed under one of the rocks, and does not know whether it [is the one that] towers above the Tum'ah.

Question: This is explicitly taught in the Seifa (54a) - one does not shave for Sechachos and Pera'os!

Note: Our text says Even ha'Sechuchis. It seems that Tosfos holds that Even ha'Sechachos is Pera'os. He cited also Sechachos, for they are the first matter listed in the Mishnah. Even ha'Sechachos cannot be Sechachos of the Mishnah, for that refers to a tree (54b).

Answer: We must say that also here, the Tana teaches [concisely] and later explains, just like regarding a bone the size of a barley seed.

Question: What was the question [that it is Tamei due to Etzem ki'Se'orah]? We discuss Tum'as Ohel, and a bone the size of a barley seed is not Metamei b'Ohel!

Answer (Ri): [The Makshan] relies on what he wants to say below, that after the Reisha taught for half Kav of bones, which implies not for less, why did the Seifa need to teach a quarter Kav of bones, that a Nazir does not shave for them?

[The Gemara] answers below that it comes to infer that for less than a half Kav, he does not shave for Ohel, but he shaves for touching or moving.

Consequence: The primary Chidush of our Mishnah is to teach that he shaves for touching or moving. Therefore, now we infer that it is obvious that he shaves for less than a half Kav, for touching or moving it, due to a bone the size of a barley seed!

We answer that the case is, they were ground like flour or earth. In such a case, it is not Metamei due to Etzem ki'Se'orah.

Explanation: Metal Kelim that touch a Mes become Avi Avos ha'Tum'ah like a Mes itself, to be Metamei a person who touches them Tum'as Shivah (he must receive Haza'ah on day three and day seven to become Tahor), like one who touches a Mes itself;

Or (i.e. also it is like a Mes) to be Metamei one who enters the Ohel in which the sword is, Tum'as Shivah, like one who enters Ohel ha'Mes.

Explanation (cont.): "Oh b'Mes" teaches about a limb that came off the Mes that has enough flesh that such a limb on a living person could heal. [The limb] is considered like a Mes itself.

"Oh b'Etzem Adam" teaches about quarter Kav of bones. It is Metamei b'Ohel. A tradition from Moshe from Sinai requires a quarter Kav. The verse is a mere Asmachta.

Citation of Gemara: ["Oh b'Kever" -] this is a sealed coffin.

Explanation: It was taught that Tum'ah pierces and ascends from the coffin and pierces and descends from it.

Suggestion: This sealed coffin is when there is not an open [hollow cubic] Tefach [above the Tum'ah].

Rejection: That is Tum'ah Retzutzah. It is Metamei only what is opposite (directly above or below) the body of the Mes;

Here, the coffin itself is Metamei, even not opposite the Mes. Rather, here we discuss a coffin sealed on every side, and there is an open Tefach between it and the Mes.

Distinction: This is unlike Tum'ah Retzutzah, for here the coffin itself is Metamei b'Ohel, even not opposite the Mes.

Support: It says so in the Sifri. "Oh b'Kever" teaches about a sealed coffin. It is Metamei all sides, even the empty part of it.

Limitation: This is only if there is an open Tefach between the Mes and the coffin over it. If there is an open Tefach it is not Metamei all sides. Rather, the Tum'ah pierces and ascends opposite it, i.e. only directly above the Mes.

Proof (R. Shimshon): It says in Ohalos (7:1) that one who touches Nefesh Atum'ah from the sides is Tahor, because the Tum'ah pierces and ascends and pierces and descends;

If the place of the Tum'ah was a Tefach [long] and a Tefach [wide], he is Tamei, for it is like a sealed coffin.

Implied question: It says in Berachos (19b) that most coffins have an open Tefach [therefore it was permitted to pass over them in order to see kings]!

Answer: We must say that those graves were open from the side. [A coffin] gets the law of a sealed coffin only if all of the sides are closed.

Support (Ohalos 3:7 - Mishnah): A covered sewage channel under a house - if it has an open Tefach, if it has an open Tefach [above the Tum'ah], and there is an open [square] Tefach at the exit [to Reshus ha'Rabim], if there is Tum'ah inside it, the house is Tahor.