(Beraisa - R. Yosi): It is Tahor.

Question: (R. Yosi responded to Chachamim.) Which teaching did he address?

He cannot discuss (either law of) the Seifa, for also Chachamim are Metaher!

Answer: Rather, Chachamim have two reasons to be Metamei, and he argues about both:

In the Reisha, Chachamim are Metamei because it is the nature of Tum'ah to leave. In the Seifa, they are Metaher only because the cupboard is a Tefach deep. If not, the covered Tum'ah would pierce through;

In the Reisha R. Yosi is Metaher, for perhaps a complete k'Zayis will not leave at once, or it might be burned in its place. In the Seifa he says that it does not pass through.

Contradiction: Elsewhere, R. Yosi says that covered Tum'ah goes through the covering!

(Mishnah - R. Meir): If a dog ate flesh of a Mes and died (within three days) and is resting on the threshold, it brings the Tum'ah into the house only if the opening of its neck is (at least) a Tefach (by a Tefach);

R. Yosi says, it depends. If it (the Tum'ah inside the dog) is inside the doorway (or house), the house is Tamei. If it is outside the doorway, the house is Tahor.

R. Elazar says, if the dog's mouth is in the house (and the Tum'ah and rectum are out), the house is Tamei. if its mouth is out (and the rectum is in), the house is Tahor.

R. Yehudah ben Beseira says, in either case the house is Tamei.

Summation of question - suggestion: R. Yosi discusses when the neck is not a Tefach thick. Even though the Tum'ah is covered, it pierces through and it is Metamei the house (if it is inside the doorway)!

Answer (Rava): No. R. Yosi says that we look at the interior of (what brings) the Tum'ah (i.e. the neck, if it is a Tefach by a Tefach). He argues with R. Meir about two matters;

R. Meir says that if the neck is a Tefach, it brings Tum'ah. R. Yosi says the interior must be a Tefach;

R. Meir holds that the roof above the entire threshold brings Tum'ah to the house. R. Yehudah says so only for the part inside the doorway.

Support: In Rav Acha brei d'Rava's text of the Beraisa, R. Yosi explicitly says 'we look at the hollow in which the Tum'ah is.'

Question: Who is the Tana that argues with R. Yosi and says that towering is not called touching?

Answer: It is R. Shimon;

(Beraisa - R. Shimon): There are three Tum'os of Mes, each of which is Metamei in exactly two of the three possible ways:

A spoon of Rekev has Tum'as Ohel and Masa, but not Maga;

A bone the size of a barley seed has Tum'as Maga and Masa, but not Ohel;

Golel and Dofek (Rashi - the cover of a coffin and its support) have Tum'as Ohel and Maga, but not Masa.

(Mishnah): The femur of a Nevelah or Sheretz...

(Beraisa): "Nivlaso (is Tamei)", but not a femur without a hole.

Suggestion: Perhaps it is Tahor even if it has a hole!

Rejection: "One who touches will become Tamei" - something that contains Tum'ah (e.g. a bone with marrow) is Tamei only if the Tum'ah can be touched.

Question (R. Zeira): If so, one who touches the skin of a complete Nevelah should be Tahor!

Answer (Abaye): There are holes in the skin (openings of the mouth, nose and eyes).

Question (Rav Papa): One who touches the Chelev (it itself is Tahor) surrounding a kidney (of a Nevelah) should be Tahor!

Answer (Rava): Strands of meat exude from it.

Question (R. Oshaya): If one planned to puncture the femur, but did not, is it Tamei?

Is it Tahor until punctured;

Or, is it as if it was punctured?

Answer (R. Oshaya): It is Tamei.

(Mishnah): A Sheretz egg in which a Sheretz formed is Tahor; if there is a hole of any size in the egg, it is Tamei. (In the following, "Achbar"refers to a species that spontaneously generates from earth.)

If an Achbar is half (developed into) flesh, and half (still) earth, one who touches the flesh is Tamei, one who touches the earth is Tahor.

R. Yehudah says, even one who touches the earth opposite the flesh is Tamei.

(Gemara - Beraisa): "Ha'Teme'im" includes the egg and femur of a Sheretz (they are Teme'im);

Suggestion: Perhaps the egg is Tamei even if (the inside) is unformed!

Rejection: "Ha'Sharetz" - just like the Sheretz is formed, also the egg.

Suggestion: Perhaps the egg is Tamei even if there is no hole!

Rejection: "One who touches will be Tamei" - it is Tamei only if the Tum'ah can be touched.

Question: How big must the hole be?

Answer: It must be as thick as a hair, in order that a hair could enter and touch the inside of the egg.

Version #1 (Mishnah): If an Achbar is half flesh... (one who touches the flesh becomes Tamei).

(R. Yehoshua ben Levi): This is only if it has the full form of a Sheretz (on one side) from head to tail.

Version #2 (Mishnah - R. Yehudah): Even one who touches the earth opposite the flesh is Tamei.

(R. Yehoshua ben Levi): This is only if it has the full form of a Sheretz (on one side) from head to tail.

Version #1 surely agrees to (the law of) Version #2. (Without the full form of a Sheretz, R. Yehudah would say that the earth is Metamei!)

Version #2 argues with Version #1. (Chachamim say that the flesh is Metamei, even without the full form of a Sheretz.)

(Beraisa) Question: The Torah is Metamei an "Achbar" (mouse). Perhaps this includes a sea mouse (a kind of fish), which is also called Achbar!

Answer #1: Logic refutes this!

A Chuldah (weasel) is Tamei, just like an Achbar. Just like a Chuldah is only on dry land, also an Achbar!

Objection: We can learn oppositely!

A Chuldah is Tamei, just like an Achbar. Just like everything called Chuldah is Tamei, also every Achbar, even a sea mouse!

Answer #2: (It is Tamei only) "Al ha'Aretz".

Suggestion: Perhaps this teaches that a mouse is Tamei only on the ground, but not at sea!