(Mishnah): However, [the following do not cancel Nezirus and obligate Korban Tum'ah -] Sechachos or Pera'os (these will be explained);

Beis ha'Peras (a field in which a grave was lost or plowed), or Chutz la'Aretz;

A Golel (cover of a coffin, or a monument) or its supporting stones;

[Tum'as Ohel of] a Revi'is of blood, or Tum'as Ohel of a quarter Kav of bones;

Kelim that touched a Mes;

The days of Sefirah (the seven days a Metzora counts between the two times he shaves) and the days of Muchlat (after he brought a Siman of absolute Tum'ah.

For these, a Nazir does not shave [Tiglachas Tum'ah]. They sprinkle on him on days three and seven, he does not cancel the previous days counted, and he immediately resumes counting [after becoming Tahor], and there is no Korban Tum'ah for him.

B'Emes, they said that days of a Zav, Zavah and Hesger (a Metzora waiting to see if he will become Muchlat) count towards his [Nezirus].

(Gemara) Question: What is the law of Beintayim (this will be explained)?

Answer #1 (R. Yochanan): We are lenient about Beintayim.

Answer #2 (Reish Lakish): We are stringent about Beintayim.

What is Beintayim? It is Ever Min ha'Mes or Ever Min ha'Chai that does not have enough flesh.

Question (against Reish Lakish - R. Yosi): A bone k'Se'orah - do we not learn [its Tum'ah] from these verses - "Oh b'Etzem Adam", "ha'Noge'a ba'Etzem"? ("B'Etzem Adam" refers to what is recognizably from a person, i.e. a spine or skull; it has Tum'as Ohel. "Ha'Noge'a ba'Etzem" teaches a bone k'Se'orah, which has only Tum'as Maga.) Here you say that it must be k'Se'orah, and here (a limb without enough flesh, which has only Tum'as Maga, and is also learned from the latter verse) you [are Metamei it even] less than k'Se'orah!

Answer (R. Shmuel bar Avduma - Beraisa): "Ba'Chalal" (in verse 16) is [a limb with enough flesh] of any size [which is Metamei b'Ohel]. "Be'Chalal" [in verse 18] teaches about Ever Min ha'Mes or Ever Min ha'Chai without enough flesh [which has only Tum'as Maga. Just like the former is of any size, also the latter. We explained this based on SEFER NIR.]