WHICH NEVEILOS JOIN WITH EACH OTHER?
(Mishnah): All Nevelos join with each other, all Sheratzim (Tosfos - the eight mentioned in the Torah) join with each other.
(Gemara - Rav): They join only for Tum'ah. Regarding eating, (Nevelos of) Tahor animals join with each other, and Teme'im join with each other (but Tahor and Tamei do not join);
(Levi): All join even for eating;
(R. Asi): Tehorim join with each other. Teme'im join with each other.
Version #1: R. Asi argues with Rav. (Rav Asi holds that Tahor and Tamei do not join even regarding Tum'ah.)
Version #2: R. Asi agrees with Rav. (He refers only to eating.)
Question (against R. Asi - Beraisa #1): A dead cow and a live camel do not join. (Tosfos - the question is also against Rav. Surely they do not join regarding Tum'ah, rather, regarding eating!)
Inference: If both of them are dead, they join!
Answer #1: No. Rather, we infer that if both are alive, they join (to be liable for eating Ever Min ha'Chai);
The Beraisa is like R. Yehudah, who says that Ever Min ha'Chai applies to Tamei species.
Objection #1: You want to say that if both are dead, they do not join. Inf so, the Tana should have taught this (it is a bigger Chidush), instead of when only one is dead!
Objection #2 (Beraisa #2): A half-k'Zayis of a live cow and a half-k'Zayis of a dead camel do not join;
However, a half-k'Zayis of a cow and a half-k'Zayis of a camel, whether both are dead or both are alive, join.
The Seifa contradicts the Reisha! (It connotes that they always join, even if the cow is alive and the camel is dead; alternatively, it says that if both are dead they join. The Gemara knows that this Beraisa (#2) is the Seifa of Beraisa #1.)
Answer #2: This Tana holds that Isur Chal Al Isur. Rav Asi holds like Tana'im who say that Ein Isur Chal Al Isur.
(Rav): One who eats a k'Zayis of Sheratzim is lashed.
Question: What is the reason?
Answer: The Torah forbids "Achilas" Sheratzim. This refers to a k'Zayis.
Question: R. Yosi b'Rebbi Chanina recited a Beraisa that opposes this, and R. Yochanan praised it!
(R. Yosi b'Rebbi Chanina - Beraisa) Question: Why does the verse "v'Hivdaltem Bein ha'Behemah ha'Tehorah la'Teme'ah... v'Lo Seshaktzu Es Nafshoseichem ba'Behemah... uv'Chol Asher Hivdalti Lachem Letamei" begin with eating ("v'Lo Seshaktzu") and end with Tum'ah!
Answer: This teaches that just like k'Adashah (the volume of a lentil) is the Shi'ur for Tum'ah of Sheratzim, it is the Shi'ur (to be liable) for eating. (Tosfos - this challenges Rav, for a verse supports R. Yosi b'Rebbi Chanina, and no one argues with him.)
Answer: R. Yosi's teaching applies to a dead Sheretz. (It is Tamei; we equate eating to Tum'ah). Rav discusses a live Sheretz (which is Tahor).
Question (Abaye): Rav discusses our Mishnah, which discusses dead Sheratzim!
Answer (Rav Yosef): You think that he discusses our Mishnah. You are wrong. It is an independent teaching.
THE SHI'URIM FOR EATING
R. Yochanan had praised R. Yosi b'Rebbi Chanina's Beraisa.
Question: He contradicts what he said elsewhere!
(Mishnah): A limb of any size is Tamei, even a limb less than a k'Zayis of a (person or) Nevelah, or a limb less than k'Adashah of a Sheretz.
(R. Yochanan): He is not lashed unless he ate a k'Zayis.
Answer (Rava): The verse ("v'Hivdaltem... ") discusses Muvdalim (things that are different, i.e. the eight Sheratzim mentioned in the Torah that are Metamei).
Question (Rav Ada bar Ahavah): We should also distinguish among Behemos between Muvdalim and others! (Rashi - Tehorim are different (permitted to eat). The Shi'ur Tum'ah for Teme'im should be more, e.g. k'Beitzah (the volume of an egg). Tosfos - Teme'im are different, for they are forbidden. One should be liable for a limb of any size.)
Answer (Rava): They are equated regarding "v'Lo Seshaktzu" (the Lav applies to Sheratzim and Nevelos of Tahor and Tamei Behemos alike), but not regarding Shi'urim.