so that it looks like a red date, is kosher; all the more so is that the case if it was only perforated. But if the inner membrane was perforated but the outer membrane was not perforated, does the outer membrane protect the lung? Or does it not protect it, in which case the animal is a tereifa?

Rav Aḥa and Ravina disagree with regard to this question. One says: It does not protect the lung; and one says: It protects the lung. And the halakha is that it protects the lung, in accordance with the statement of Rav Yosef. As Rav Yosef says: With regard to this lung that emits a sound when inflated, if we know from where it emits a sound, we set a feather, or saliva, or straw on that point. If the saliva bubbles when the lung is inflated, the animal is a tereifa, since this proves that the lung is perforated through both membranes. And if not, the animal is kosher. And if we do not know from where it emits a sound, we bring a basin of tepid water and set the lung inside it.

One cannot place it in hot water, as it causes the lung to contract, closing the perforation. And one cannot place it in cold water, as it hardens the lung and may cause it to crack. Rather, we set it in tepid water and inflate it. If the water bubbles, the animal is a tereifa. And if not, the animal is kosher, since it is apparent that only the inner membrane is perforated and the outer membrane is not perforated, and the fact that it emits a sound is due to the air moving in the space between the two membranes. Evidently, Rav Yosef holds that if only the inner membrane is perforated, the animal is kosher.

§ The Gemara provides a mnemonic to remember the following statements of Rava with regard to the lung: Dates, red, that dried, scabbed.

The Gemara turns to the matter itself mentioned above: Rava says: This animal with a lung whose outer membrane was removed so that it looks like a red date is kosher. And Rava says: With regard to a lung whose outer membrane reddened due to bleeding of the lung, if only part of it turned red, then the animal is kosher, but if all of it turned red, the animal is a tereifa.

Ravina said to Rava: What is the reason that the animal is kosher if only part of the outer membrane reddened? Presumably, it is because the animal eventually recovers from the wound. But even if all of it turned red as well, the animal recovers. Isn’t it taught in a baraita: If one injures one of the eight impure creeping creatures mentioned in the Torah, one is liable for desecrating Shabbat; but if one injures other repugnant creatures and creeping animals, one is not liable until blood leaves their body as a result of the injury, even if their skin reddens as a result of internal bleeding?

And if you would say: We compare the lung to one of the eight creeping creatures, as it is taught in a baraita: If the blood collected under the skin of one of the eight creeping creatures, even if it did not leave the body, one is liable for desecrating Shabbat, because the blood will not be reabsorbed into the body and the wound is permanent; that is difficult: If so, then there is still no reason to distinguish between part of the lung and all of it, and even if only part of the lung turned red, the animal should be rendered a tereifa as well, because the blood will not be reabsorbed into the body. Rather, there is no difference between the reddening of part or all of the lung.

And Rava says: If part of the lung was dried, the animal is a tereifa. And how much must the lung be dried so as to render the animal a tereifa? Rav Pappi says in the name of Rava: It must be so dry that it can be crumbled with a fingernail.

The Gemara asks: In accordance with whose opinion is this statement? Is it in accordance with the opinion of Rabbi Yosei ben HaMeshullam? As it is taught in a mishna (Bekhorot 37a): If a kosher firstborn animal has a blemish, such as a dried ear, it may be slaughtered outside the Temple. What is a dried ear? It is any ear that if perforated does not bleed a drop. Rabbi Yosei ben HaMeshullam says: It must be so dry that it can be crumbled with a fingernail.

The Gemara responds: You may even say that the statement is in accordance with the opinion of the Rabbis. With regard to the ear of a firstborn, which is exposed to the wind, the Rabbis hold that the animal would not recover if it is so dry that it does not bleed. But with regard to the lung, which is not exposed to the wind, the animal would recover unless it is so dry that it can be crumbled with a fingernail. And Rava says: This lung that stands before us covered in scabs, or covered in black marks, or covered in sores with different appearances, is nevertheless kosher.

§ Ameimar says in the name of Rava: One may not compare cysts of the lungs. If one finds a perforated cyst on the lung, but does not know whether it was perforated before or after slaughter, he may not perform a test by perforating another cyst in order to compare their appearances.

And Rava says: These two lobes of the lung that adhere to one another by thin strands have no need for inspection, since it is certain that these adhesions arose due to a perforation of the lung, rendering the animal a tereifa. The Gemara adds: And we said this halakha only with regard to adhesions that are out of order, where a lobe adhered to a non-adjacent lobe. But with regard to adhesions that are in order, that is their normal manner of growth, and the animal is kosher.