OPINIONS: Rava states that the lungs are comprised of five small, upper (cranial) lobes (in addition to the two large, lower (caudal) lobes) -- three on the right side of the animal, and two on the left side of the animal. Rava rules that if the animal has an extra lobe ("Una"), then the animal is a Tereifah. Mereimar argues and rules that as long as the extra lobe is in line with the other lobes, the animal is Kosher. Only when the extra lobe is out of line with the other lobes ("Beini Beini") is the animal Tereifah. RASHI writes that an example of an extra lobe that is out of line with the other lobes is the "Inonisa d'Varda," the small (intermediate) lobe that is nearly centered on the underside of the lungs, between the two large, lower lobes.
The Gemara continues with a case of an extra lobe that was "Beini Beini" that came before Rav Ashi. Rav Ashi initially wanted to pronounce the animal a Tereifah, but Rav Huna bar Avya argued that all animals that are "Beriyasa" (that graze outside ("Bara"), or that are healthy and fat ("Bari"); see RASHI) all have such an extra lobe. It is called the "Inonisa d'Varda" because it is a small lobe that resembles a rose ("Vered").
What type of lobe constitutes an extra lobe that is "Beini Beini" and renders the animal a Tereifah?
(a) TOSFOS (DH Kol) writes that since the Inonisa d'Varda is not a sign of a Tereifah, the type of extra lobe that is "Beini Beini" and that renders the animal a Tereifah must be a lobe that is very large and is not similar to the Inonisa d'Varda.
The RASHBA writes that if the Inonisa is as large as the other lobes, the animal is a Tereifah, because the nature of the Inonisa is to be small. The SHACH (YD 35:9) cites the YAM SHEL SHLOMO who rules that even if the Inonisa is only as large as the middle lobe on the right side (the middle right cranial lobe), the smallest of the five upper lobes, then the animal is a Tereifah because it is no longer similar to an Inonisa. The Shach adds that this also seems to be the opinion of the REMA (YD 35:2) who states simply that if the Inonisa's form differs from its usual form, then the animal is a Tereifah.
(b) RASHI (DH Afilu) writes that most of the animals of his time possessed an Inonisa, and thus any animal that has one is certainly Kosher. However, even in Rashi's time, if the lung did not possess an Inonisa, the animal was still Kosher (as in the time of the Gemara). Rashi also writes that he heard from his teacher that the Gedolei ha'Dor (Rebbi Yehudah ben Rebbi Baruch and his colleagues) had a dispute about an animal that has two Inonisas. Rashi's teacher did not relate to him his opinion on this matter, though. Rashi himself writes that his own opinion is that the animal is a Tereifah, because it is an extra lobe out of line of the other lobes. The Gemara permits an animal that has even one Inonisa only because all animals that graze outside (or that are healthy) possess one. Since it is uncommon for an animal to possess two Inonisas, such an animal is a Tereifah.
(c) Tosfos cites RABEINU EFRAIM who maintains that an animal that possesses two Inonisas is Kosher, but if it possesses no Inonisa it is a Tereifah (this is the opposite of Rashi's view). Rabeinu Efraim's reasoning is that since all animals of his time (even those that did not graze outside) possessed an Inonisa, it could not be that Rav Ashi considered such an animal to be a Tereifah. Rather, Rav Huna bar Avya must have meant that animals that graze outside have two Inonisas, and thus all animals that have two Inonisas are Kosher. Consequently, an animal that has no Inonisa is a Tereifah according to Rabeinu Efraim, because domesticated animals possess at least one, but no animals possess none.
Tosfos disagrees with Rabeinu Efraim (see also TOSFOS HA'ROSH). Tosfos asserts that animals of modern times are not comparable to animals of the time of the Gemara, because the natural world has changed in a number of ways (see REMA EH 156:4). Tosfos understands that animals that grazed outside in the time of the Gemara possessed one Inonisa, while domesticated animals possessed none. Therefore, Tosfos writes that the practice follows the opinion of Rashi.
However, the REMA (YD 35:2) states that the practice is to prohibit both an animal that has two Inonisas and an animal that possesses none. (D. BLOOM)


OPINIONS: Rav Nachman rules that an animal whose lung withered remains Kosher as long as the membrane is intact. RASHI (DH Nimokah) explains that the lung's flesh liquefied and emptied out, but it was not full of fluid like a bottle (in which case the animal would be Tereifah, as the Gemara earlier says; see Insights to 45:2). Rather, in one part of the inside of the lung nothing remained. The Gemara cites a Beraisa to support Rav Nachman's ruling. The Beraisa states that when a lung becomes empty but its membrane is intact, the animal is Kosher even if the hollow part can contain a Revi'is.
What is the Halachah if the hollow part is larger than the volume of a Revi'is? Does the Beraisa mean that the animal is Kosher only when the missing part of the lung is not larger than a Revi'is, or does the Beraisa mean that when the missing part is very large, it is Kosher (and the "Revi'is" that it mentions is an exaggeration)?
(a) The RASHBA (cited by the TAZ YD 36:14) rules that the animal is permitted even when more than a Revi'is of the inside of the lung is missing. The KEREISI U'PLEISI infers from the words of the RAMBAM that he also maintains that such an animal is Kosher. When the Beraisa says that the animal is Kosher "even when it (the missing part of the lung) can hold a Revi'is," it mentions a Revi'is only to emphasize that the animal is Kosher even when a very large amount of the lung is missing.
(b) The REMA (YD 36:8) writes, "When some flesh inside the lung is missing, even if the missing part has the volume of a Revi'is, the animal is Kosher. However, if more than a Revi'is is missing, then the animal is a Tereifah." The Rema clearly learns that the Beraisa means that only when the missing part of the lung is less than a Revi'is is the animal Kosher.
This stringent opinion cited by the Rema infers from the fact that the Gemara mentions a Revi'is that a lung missing more than a Revi'is renders the animal a Tereifah. (The Taz disagrees with this inference and says that since Rav Nachman is an Amora, he is required to explain his intent more explicitly than a Tana is required. Therefore, if Rav Nachman meant that when more than a Revi'is is missing the animal is a Tereifah, then he should have stated this explicitly.)
It is evident that RASHI agrees with the stringent ruling. Rashi (DH Afilu) explains that the part of the lung in which the flesh is missing has the volume of a Revi'is of a Log. Why does Rashi say that the Revi'is mentioned in the Gemara refers to a Revi'is of a Log? Whenever the Gemara mentions a Revi'is without specifying the specific measure, it refers to a Revi'is of a Log, as Rashi himself writes in a number of places (see Shabbos 77a, DH Tanina)! It must be that Rashi is emphasizing that when the Beraisa mentions a Revi'is, it means a specific volume (and it does not mean any large amount). Rashi therefore says that this specific Revi'is is a Revi'is of a Log, so that we will know that anything more renders the animal a Tereifah. (D. BLOOM)