Correction (Rav Mordechai, citing Reish Lakish): Rather, when we learn from one source (e.g. Kal va'Chomer), we challenge only from a leniency or stringency;

When we learn from two sources, we may challenge from anything common to the sources (which is not found in the Lamed);

When we learn from three sources, if we (can challenge the third source from a leniency or stringency, and) must learn from a Tzad ha'Shavah, we may challenge from anything common to the sources;

If we need not learn from a Tzad ha'Shavah, we challenge only from a leniency or stringency.

Qestion: We should challenge that Kilayim was never permitted, but Basar v'Chalav were permitted before they were cooked together!

Answer (Rav Ada bar Ahavah): Since we do not ask this, it must be that regarding Kil'ai ha'Kerem, what was planted (the tree, vine or seeds, which were initially permitted) becomes forbidden, so this is just like Basar v'Chalav.

Question (Rav Shemaya bar Ze'ira - Mishnah): If one passes a holed flowerpot through a vineyard:

If what is growing in the pot grew another one part in 200 (while passing through), it is forbidden;

If it did not grow more, it is permitted!

Answer (Abaye) Contradiction: One verse says "Pen Tikdash ha'Mele'ah" (only additional growth becomes forbidden). Another verse forbids "ha'Zera";

Resolution: If it was Kil'ayim when planted, it is forbidden once it takes root;

If it was planted b'Heter, and later grew in a situation of Kil'ayim, it is forbidden only if it grew another one part in 200.

Our Mishnah is not like the following Tana;

(Beraisa - R. Shimon ben Yehudah): One may not eat Basar v'Chalav, but it is Mutar b'Hana'ah.

One verse forbidding Basar v'Chalav says "you are a Kodesh nation to Hash-m." Another verse says "you will be Kodesh people to me (do not eat Terefah meat)";

Just like Terefah may not be eaten but it is Mutar b'Hana'ah, also Basar v'Chalav.

(Mishnah - R. Akiva): The Isur does not apply to Chayos and birds (and Tamei animals. These are excluded by the three times it says "Gedi" in the verses of Basar v'Chalav.)

Question: We need these to learn what Shmuel (113b) expounded from them!

Answer: R. Akiva does not need verses to teach (three of) Shmuel's laws;

He holds that in general, Isur Chal Al Isur (so Basar v'Chalav applies to Chelev and Nevelah);

He holds that a fetus is a fully-fledged kid (so Basar v'Chalav applies to it).

Therefore, he expounds all three "Gedi"s like above.

(Mishnah - R. Yosi ha'Glili): It says "do not eat a Nevelah... "

Question: What do R. Akiva and R. Yosi ha'Glili argue about?

Answer #1: R. Yosi ha'Glili holds that mid'Oraisa, Basar v'Chalav applies to Chayos. R. Akiva holds that this is only mid'Rabanan;

Answer #2: They argue about fowl;

R. Akiva holds that mid'Oraisa, Basar v'Chalav does not apply to fowl. This implies that mid'Rabanan it applies;

R. Yosi ha'Glili holds that it does not apply to fowl even mid'Rabanan.

Support (Beraisa): In R. Eliezer's region, (when a Bris Milah occurred on Shabbos they would arrange that there was no knife available. This required that) they would cut trees to make coals to make a knife (R. Eliezer permits all preparations for Milah);

In R. Yosi ha'Glili's region, they would eat fowl cooked with milk.

Levi visited the house of Yosef the bird-trapper. They served peacock with milk. He did not comment.

Rebbi: Why didn't you excommunicate them?

Levi: That is the region of R. Yehudah ben Beseira. Presumably, he taught them like R. Yosi ha'Glili, who permits this.

(Mishnah): The stomach of a Nochri's animal or of a Nevelah is forbidden. (In this Sugya, 'stomach' refers to milk in the stomach unless specified otherwise.)

If one used the skin of the stomach to curdle milk, it is permitted;

If the milk absorbed the Ta'am of meat, it is forbidden.

If a Kosher animal nursed from a Terefah, the stomach is forbidden;

If a Terefah nursed from a Kosher animal, the stomach is permitted, because the milk is just gathered there.

(Gemara) Question: Why does the Mishnah list separately a Nochri's animal and Nevelah? Whatever he slaughters is Nevelah!

Answer #1 (Rav Huna): The Mishnah forbids the milk even if a Yisrael bought a kid from a Nochri and slaughtered it himself. We are concerned lest it nursed from a Terefah.

Question: Are we really concerned for that?!

(Mishnah): We may buy eggs from Nochrim. We are not concerned lest they are from a Nevelah or Terefah.

Correction: Rather, we are concerned that it nursed from a Tamei animal.

Question: Why are we more concerned for nursing from a Tamei animal than from a Terefah?

Answer: Tamei animals are more common than Terefos.

Question: If so, we should be concerned even regarding animals of a Yisrael!

Answer: If a Yisrael sees his animal nursing from a Tamei animal, he will separate it. Therefore, Chachamim did not decree;

If a Nochri sees this, he will leave it, so Chachamim decreed.

Answer #2 (Shmuel): The Mishnah states one case, i.e. the stomach of an animal slaughtered by a Nochri, which is a Nevelah.

Contradiction: Shmuel taught that cheese of Nochrim is forbidden because they use the skin of the stomach of Nevelah to curdle it;

Inference: The (milk in the) stomach is permitted!

Resolution: Originally, the Mishnah forbade (milk in) the stomach (of a Nochri's animal, and Shmuel explained that this is because it is a Nevelah);

Shmuel explained why cheese of Nochrim is forbidden according to the conclusion.

(Mishnah): If a Kosher animal nursed from a Terefah, the stomach is forbidden. If a Terefah nursed from a Kosher animal, the stomach is permitted.

Question: The Reisha forbids the stomach of a Nochri's animal or of a Nevelah!

Answer #1 (Rav Chisda): Eating something (milk) found in a Nevelah looks like eating a Nevelah, so Chachamim forbade it;

A Terefah was slaughtered, so it does not look like eating a Nevelah, so Chachamim permit it.

Objection (Rava): We should say just the contrary!

Nevelah is repulsive. Even if the milk inside was permitted, no one would come to eat the Nevelah. Even so, the milk is forbidden;

Terefah is not repulsive. If the milk was permitted, people might come to eat the Terefah. All the more so, Chachamim should forbid it!

Answer #2 (Rav Yitzchak): The Reisha was the original version. Milk inside a Nevelah (or Terefah) is forbidden;

The Seifa is the revised version. Milk inside a Terefah (or Nevelah) is permitted.

Since people were used to the original version, it was left in the Mishnah.

(R. Chiya bar Aba citing R. Yochanan): We may curdle (milk) using the (milk in the) stomach of a Nevelah, but not of an animal slaughtered by a Nochri.

Question (R. Shimon bar Aba): Is this like R. Eliezer, who presumes that all acts of a Nochri are for idolatry?

Answer (R. Chiya bar Aba): Of course it is!

(Rav Shmuel bar Rav Yitzchak citing R. Yochanan): We may curdle using the (milk in the) stomach of a Nevelah, or an animal slaughtered by a Nochri. We are not concerned for R. Eliezer's opinion.

Version #1 (our text, Tosfos): The Halachah is, we not may curdle in the skin of the stomach of a Nevelah;

We may use (congealed milk in) the stomach of the following;

A Nevelah or an animal slaughtered by a Nochri;

A Kosher animal that nursed from a Terefah, and all the more so a Terefah that nursed from a Kosher animal.

This is because congealed milk in the stomach is considered like Pirsha (a secretion, or waste. It is no longer forbidden.)

Version #2 (Rashi): The Halachah is, we may not curdle in the skin of the stomach of a Nevelah;

We may use the (milk in the) stomach of a Nevelah or an animal slaughtered by a Nochri (if it nursed from a Kosher animal, because the milk inside is merely gathered, it is not like part of the kid).