1) EXCISION OF THE SPLEEN OR KIDNEYS
QUESTION: The Mishnah states that when the spleen (Techol) or kidneys (Kelayos) of an animal are excised from the animal but left inside of the animal, the subsequent Shechitah of the animal does not permit those organs to be eaten. They are forbidden because of the Isur of Ever Min ha'Chai, since they were cut off while the animal was alive. This is in contrast to a fetus inside the animal, which is permitted by the Shechitah even if it is cut up before the Shechitah.
RASHI (DH Asur) explains that the reason why the Mishnah gives the example of cutting the spleen or kidneys is that the removal of these organs does not render the animal a Tereifah.
These words of Rashi are difficult to understand in light of the Gemara earlier (55a). In the Gemara there, Rav Avira states that even though an animal is not a Tereifah when it is lacking a spleen, when it possesses a spleen but the spleen has a puncture in it, the animal is a Tereifah. The Gemara there questions Rav Avira's statement from the Mishnah here, which implies that even when the spleen or kidneys themselves are forbidden, the animal is permitted. The Gemara there answers that in fact the animal itself is also prohibited because of the puncture in the spleen or kidney. The Mishnah says only that the spleen and kidneys are forbidden in order to contrast and distinguish them from the fetus in the first part of the Mishnah, which is permitted when it is cut up inside the womb.
Why, then, does Rashi say that the animal does not become a Tereifah when the spleen and kidneys are cut? The Gemara earlier clearly says that the animal is a Tereifah and is forbidden to eat when the spleen and kidneys are cut!
(The TOSFOS YOM TOV actually rejects Rashi's explanation on the basis of this question. He explains instead that the reason why the Mishnah mentions specifically the spleen and kidneys is that those organs are frequently cut. The Mishnah is merely discussing the most common case.)
(a) The RASHBA answers that Rashi here follows the second answer given in the Gemara earlier. In its second answer there, the Gemara says that only a puncture in the spleen renders the animal a Tereifah; cutting off the spleen does not render the animal a Tereifah.
The Rashba adds that perhaps Rashi explains the Mishnah here according to the second answer of the Gemara earlier not because he rules like that answer, but because the most straightforward reading of the Mishnah here is that the animal is Kosher when the spleen and kidneys are cut. (See also TOSFOS YOM TOV to Pe'ah 2:2 who explains that it is the style of Rashi, as evident in many places, to explain the Mishnah according to the initial understanding of the Gemara, even when the Gemara's conclusion is otherwise.)
It could be that Rashi is in doubt about whether the Halachah follows the first or second answer of the Gemara earlier. The Rashba writes that since there are two answers in the Gemara, and the Gemara does not state which one the Halachah follows, one must be stringent in practice, since an Isur d'Oraisa (of Tereifah) is involved, and one should not eat an animal from which the spleen or kidneys were removed before Shechitah.
(b) Even though the Tosfos Yom Tov rejects Rashi's explanation (as mentioned above), in the MA'ADANEI YOM TOV (4:1:1) he gives an answer for Rashi. He writes that the Gemara earlier (55b) states that the Halachah does not follow the view of Rav Avira, who says that a hole in the spleen renders the animal a Tereifah. However, the Gemara there adds that if the hole was at the thick end of the spleen, then the animal is a Tereifah. The animal is Kosher only if the hole is in the thin end of the spleen. Accordingly, when Rashi here says that a spleen that was cut does not render the animal a Tereifah, he is referring to a spleen that was cut at its thin end. Such a cut does not render the animal a Tereifah.
The Ma'adanei Yom Tov cites support for this answer from the words of the RAN (end of 16b of the pages of the Rif). The Ran writes that once the Gemara distinguished between a hole in the thin part and a hole in the thick part, it is no longer necessary to distinguish between a cut and a puncture (as the second answer of the Gemara there does). (D. BLOOM)
2) A FETAL LIMB THAT PROTRUDED FROM THE WOMB
OPINIONS: The Mishnah (68a) states that when part of an unborn animal protruded from its mother's womb and then returned to its place before the Shechitah of the mother, "it is permitted to be eaten."
Rav Yehudah in the name of Rav (68a) says that only the fetus inside of the mother is permitted, but the limb that emerged is prohibited, even when it withdrew back into the womb. Ula in the name of Rebbi Yochanan (68b) says that the limb itself is permitted when it returned to the womb.
The Gemara records a second version of the argument between Rav and Rebbi Yochanan, according to which Rav says that "Yesh Leidah l'Evarim" -- a limb that leaves the womb is considered to have been born. Rebbi Yochanan says that "Ein Leidah l'Evarim" -- a limb that leaves the womb is not considered to have been born.
The Gemara asks, "What is the difference between them?" It answers that the difference is in a case in which a majority of the limb emerged, but a minority of the limb remained inside of the womb.
There are a number of approaches in the Rishonim to understanding the second version of the argument between Rav and Rebbi Yochanan (and the subsequent questions and answers of the Gemara), and what the Gemara means when it discusses "the difference between them."
(a) The RIF and most Rishonim explain that according to the second version, Rebbi Yochanan agrees that the limb remains prohibited when it is retracted back into the womb. According to this version, the argument involves a case in which a majority of the limb exited, while part of it remains inside the womb. Does the majority of the limb that exited cause the part of the limb that remains inside of the animal to become prohibited? Rav maintains "Yesh Leidah l'Evarim," and thus the entire limb is considered to have emerged from the womb (because of the majority that exited) and it is prohibited (even the minority that remains inside the animal), even when the majority returns to the womb. Rebbi Yochanan maintains "Ein Leidah l'Evarim," and thus the only part that is prohibited is the part that actually exited, but not the part that remains inside the womb.
According to this approach, when the Gemara asks, "What is the difference between them," it is asking what is the difference between Rav and Rebbi Yochanan in the second version (but not what the difference is between the first version and the second version).
It seems that there are two ways to understand the opinion of Rav, who says that the minority of the limb that is inside the womb becomes prohibited even when the majority reenters the womb. One way to understand this is that the minority becomes prohibited because of the principle of "Rubo k'Chulo." Since the majority exited, it is considered as though the minority that remains inside the womb also exited. Another way to understand this is implied by the words of Rav, "Yesh Leidah l'Evarim." These words imply that Rav maintains that there is a concept of birth for a single limb. Just as the fetus itself is considered to have been born once a majority (or the head alone) exits the womb, and the law of "Ben Paku'a" no longer applies even to the minority of the fetus that remains in the womb because the fetus is no longer considered part of its mother (but not because of the law of "u'Vasar ba'Sadeh Tereifah Lo Sochelu"), so does the status of "being born" apply to a limb whose majority left the womb. (See KUNTRUS ATERES ZEKENIM, #6-9, by Rav Moshe Pogrow.)
(b) RASHI explains that Rebbi Yochanan's opinion in the second version is the same as his opinion in the first version. Rebbi Yochanan says that the limb that exits the womb and then returns to it is not prohibited. Rav's opinion, though, is different in the second version. Rav maintains that not only does the limb that exited remain prohibited when it returns to the womb (as he says in the first version), but the part of the limb that never exited also becomes prohibited when a majority of the limb exited (again, either because of "Rubo k'Chulo," or because there is a concept of "birth" for a single limb).
According to Rashi, when the Gemara says that the difference between the two versions is a case in which a majority of the limb exited, it is teaching the difference between the first version of Rav and the second version of Rav (as Rashi says explicitly in DH Mai Beinaihu).
(c) The RAMBAN records a third approach, according to which the second version of the argument between Rav and Rebbi Yochanan is entirely unrelated to the first version. The first version discusses whether retracting the limb back into the womb makes it permitted. The second version discusses -- when the limb did not go back into the womb -- whether the part of the limb that remains inside the womb is prohibited; does a minority become prohibited because of the majority? Rav says that the part inside of the womb becomes prohibited, while Rebbi Yochanan says that it does not. (The ROSH YOSEF adds that according to this explanation, both Rav and Rebbi Yochanan agree that when the part of the limb that was outside of the womb comes back into the womb, the part that never emerged is certainly permitted.)