The fat that is covered by the flesh is permitted. Apparently, when the Merciful One states in the Torah that the fat that is upon the loins is prohibited (see Leviticus 3:4), it is referring only to the fat above the loins but not the fat that is inside the loins. Here also, the Merciful One states in the Torah that the fat that is upon the kidneys is prohibited (see Leviticus 3:4), but this does not include the fat that is inside the kidneys.

§ The Gemara addresses the matter itself cited in the discussion above: Rabbi Abba said that Rav Yehuda said that Shmuel said: The fat that is covered by the flesh is permitted. The Gemara asks: Is that so? But didn’t Rabbi Abba say that Rav Yehuda said that Shmuel said: This fat that is under the loins is forbidden, even though it is covered by flesh?

The Gemara answers that Abaye said: When an animal is alive its limbs separate at the joints as it walks, so that the fat under the loins is not covered by flesh. Therefore, even after it has been slaughtered this fat is forbidden and does not have the status of fat that is covered by flesh. Rabbi Yoḥanan said: I am not a butcher and I am not the son of a butcher, i.e., I am not expert in the anatomy of animals, but I remember that this is what they would say in the study hall: When an animal is alive its limbs separate at the joints as it walks, so that the fat under the loins is exposed.

§ Rabbi Abba said that Rav Yehuda said that Shmuel said: The fat that is on the omasum and the reticulum is forbidden, and its consumption is punishable by karet. And this is the fat that is referred to in the Torah as being upon the innards (see Leviticus 3:3). Rabbi Abba said that Rav Yehuda said that Shmuel said: This fat of the coccygeal bone is forbidden, and its consumption is punishable by karet. And this is the fat that is referred to in the Torah as being upon the loins (see Leviticus 3:4).

And Rabbi Abba said that Rav Yehuda said that Shmuel said: The veins that are in the foreleg of an animal are forbidden. Rav Safra said to Rabbi Abba: Moses! Did the Merciful One say in the Torah: Do not eat meat? The veins of the foreleg are part of the meat and are not forbidden. Rava said: Moses! Did the Merciful One say in the Torah: Eat blood? The reason that these veins are forbidden is that they are filled with blood. Therefore, if one cuts the foreleg open and salts it to remove the blood, it is permitted even to cook it in a pot; and it is certainly permitted to roast it over a fire, which also draws out the blood.

Rav Yehuda said that Shmuel said: The fat on the top cubit of the small intestine requires scraping, i.e., it is forbidden and must be removed. And this is the fat referred to by the Sages (see 49b) as the fat that is on the small intestine.

And Rav Yehuda says: The sinews that are in the tailbone are forbidden for consumption, because they contain forbidden fat. There are five sinews in the tail: Three on the right and two on the left. The three on the right each split into two, and the two on the left each split into three. The practical difference, i.e., the reason the Gemara describes this in detail, is that if one draws them out while they are still warm soon after slaughter they are drawn out easily, but if not, he is required to scrape around them, i.e., dig into the flesh to remove them. It is important to know how many there are to ensure that one removes them all.

Abaye said, and some say that Rav Yehuda said: There are five strands that are forbidden for consumption; three of them are forbidden because they contain forbidden fat, and two are forbidden because they contain blood. The ligaments of the spleen and of the tail and of the kidneys are forbidden because they contain forbidden fat. And the veins of the foreleg and of the pharynx, i.e., the carotid artery, are forbidden because they contain blood.

The Gemara asks: What difference is there whether they are forbidden due to fat or due to blood? The Gemara answers: With regard to these veins and arteries that are forbidden because they contain blood, if one cuts them open and then salts them to remove the blood they are permitted. But those strands that contain forbidden fat have no rectification and can never be eaten.

Rav Kahana said, and some say that it was Rav Yehuda who said: There are five membranes that are forbidden for consumption; three of them are forbidden because they contain forbidden fat, and two are forbidden because they contain blood. The membranes of the spleen and of the tail and of the kidneys are forbidden because they contain forbidden fat. And the membranes of the testicles and of the brain are forbidden because they contain blood.

The Gemara relates that Rav Yehuda bar Oshaya was peeling the membranes from a spleen for Levi, son of Rav Huna bar Ḥiyya. He was cutting them only from the upper surface of the spleen. Levi said to Rav Yehuda: Go down further, i.e., remove the fat that is lower down as well. Levi’s father, Rav Huna bar Ḥiyya, came and found him as Levi was saying this to Rav Yehuda. Rav Huna bar Ḥiyya said to him: This is what your mother’s father said in the name of Rav; and who was Levi’s mother’s father? It was Rav Yirmeya bar Abba. He said: The Torah prohibits only the membranes that are on the thick, upper surface of the spleen.

Levi asked: Is that so? But didn’t Rav Hamnuna say that it was taught in a baraita that the membrane that is on the spleen is forbidden, but one is not liable to receive the punishment of karet for eating it? Levi clarifies: What are the circumstances referred to in the baraita? If we say that it is referring to the membranes that are on the thick, upper surface of the spleen, why is one not liable to the punishment of karet for eating it? Rather, it must be referring to the membranes on all sides of the spleen, even the underside. Rav Huna bar Ḥiyya said to his son, Levi: If this baraita is taught, it is taught, and I cannot take issue with it.

§ The Gemara returns to discuss the matter itself mentioned above: Rav Hamnuna said that it was taught in a baraita: The membrane that is on the spleen is forbidden, but one is not liable to receive karet for eating it. The membrane that is on the kidney is forbidden, but one is not liable to receive karet for eating it. The Gemara challenges this statement: But isn’t it taught in a baraita that one is liable to receive karet for eating the membrane on the spleen or the kidney?

The Gemara answers: The apparent contradiction between the baraita that states that one is not liable to receive karet for eating the membrane on the spleen and the baraita that states that one is liable to receive karet for eating the membrane on the spleen is not difficult: This baraita that states that one is liable is referring to the membrane on the thick, upper part of the spleen, whereas that baraita that states that one is not liable is referring to the membrane that is not on the thick part of the spleen.

Likewise, the apparent contradiction between the baraita that states that one is not liable to receive karet for eating the membrane on the kidney and the baraita that states that one is liable to receive karet for eating the membrane on the kidney is not difficult: This baraita that states that one is liable is referring to the membrane on the upper part of the kidney, whereas that baraita that states that one is not liable is referring to the membrane on the lower part of the kidney.

§ With regard to testicles that were crushed while the animal was alive but were still attached to their cords in the scrotum, there is a dispute between Rav Ami and Rav Asi. One of them prohibits eating the testicles after the animal is slaughtered and one of them permits eating them. The Gemara clarifies: The one who prohibits them holds that