If one suggests: Let us slaughter it and then we will examine it to determine whether its windpipe was severed or its gullet was perforated, that is difficult, because perhaps the slaughterer will slaughter the duck precisely in the place of the perforation and it will be impossible to determine whether the gullet was perforated before the slaughter. If one suggests: Let us slice open the hide and examine the simanim and then we will slaughter it, that is difficult, because didn’t Rabba say: The gullet has no possible examination from without, as its outer side is red, and a small perforation would be indiscernible, but only from within, as its inner side is white, and blood at the site of the perforation would be discerned?

Rav Yosef, son of Rava, said to him: Let us examine the windpipe, as it is possible to discern from without whether the majority of the windpipe was severed, and then cut the duck’s windpipe and thereby render it permitted, as cutting either of the two simanim suffices in a bird. And then let us turn the gullet inside out and examine its inner side to determine whether it was perforated and the duck is a tereifa. Rava said: My son Yosef is as wise in the halakhot of tereifot as Rabbi Yoḥanan. Apparently, one siman, which is taught in the mishna as being sufficient in the slaughter of a bird, means either this siman, the gullet, or that siman, the windpipe.

§ The mishna states: Rabbi Yehuda says: The slaughter is not valid until he cuts the veins in the neck. Rav Ḥisda said: Rav Yehuda said that one must cut the veins only in the slaughter of a bird, as one typically roasts it in its entirety as one whole entity; therefore, one must cut the veins to ensure that the blood drains. But with regard to the slaughter of an animal, since it is typically quartered into limbs, resulting in the blood draining more readily, one need not cut the veins.

The Gemara asks: Is that to say that the reason that Rabbi Yehuda requires cutting of the veins is due to the need to drain the blood? But didn’t we learn in the mishna: Rabbi Yehuda says: The slaughter is not valid until he cuts [sheyishḥot] the veins, indicating that the cutting of the veins is a component of the slaughter [sheḥita]?

The Gemara answers: Say that Rabbi Yehuda’s statement is until he punctures the veins. And what is the meaning of: Until he cuts? Until he punctures the veins at the moment of slaughter, when the blood flows.

The Gemara suggests: Come and hear proof rejecting this interpretation of Rabbi Yehuda’s statement from a baraita: The veins through slaughter, this is the statement of Rabbi Yehuda, which indicates that the cutting of the veins is a component of slaughter. The Gemara rejects that proof: Say that the correct reading of the baraita is: He must puncture the veins at the moment of slaughter; this is the statement of Rabbi Yehuda.

The Gemara suggests: Come and hear another proof from a baraita: The Rabbis said to Rabbi Yehuda: Since veins were mentioned only to drain blood from them, what difference is there to me whether one cuts them as a component of slaughter, and what difference is there to me whether one cuts them not as a component of slaughter? One can learn by inference from this baraita that Rabbi Yehuda holds that one cuts the veins as a component of slaughter.

The Gemara rejects this proof. This is what the Rabbis are saying to Rabbi Yehuda: What difference is there to me whether one punctures them at the moment of slaughter, and what difference is there to me whether one punctures them not at the moment of slaughter? One can puncture the veins after the slaughter. And Rabbi Yehuda holds that at the time of slaughter the blood emerges from the body quickly because the blood is warm; when it is not at the time of slaughter, the blood does not emerge from the body quickly because it is cool.

Rabbi Yirmeya raises a dilemma: In cutting the veins according to Rabbi Yehuda, if one interrupted the act in the midst of cutting them, or if he pressed the knife and cut them instead of drawing the knife back and forth, what is the halakha? Do these actions, which invalidate slaughter when cutting the simanim, also invalidate slaughter when performed in the cutting of the veins?

A certain elder said to him: This is what Rabbi Elazar said; and some say that a certain elder said to Rabbi Elazar that this is what Rabbi Yoḥanan said: He punctures the veins with a thorn and their cutting is valid. Cutting the veins is not a component of the slaughter.

The Gemara notes that it is taught in a baraita in accordance with the opinion of Rav Ḥisda that Rabbi Yehuda requires cutting of the veins only in the slaughter of birds, and not in the slaughter of animals. If one cut two halves, one half of each of the simanim, in a bird, the slaughter is not valid, and needless to say the slaughter performed in that manner is not valid in the case of an animal. Rabbi Yehuda says: In a bird the slaughter is not valid until he cuts the gullet and the veins.

§ The mishna teaches: If one cut half of one siman in a bird or one and a half simanim in an animal, his slaughter is not valid. It was stated that there is an amoraic dispute. Rav said: The halakhic status of a siman of which precisely half was cut and half remained uncut is like that of a siman of which the majority was cut. Rav Kahana said: The halakhic status of a siman of which precisely half was cut and half remained uncut is not like that of a siman of which the majority was cut.

The Gemara elaborates. Rav said: The halakhic status of a siman of which precisely half was cut and half remained uncut is like that of a siman of which the majority was cut, and this is what the Merciful One said to Moses: Do not leave the majority uncut. When cutting precisely half, the majority does not remain uncut. Rav Kahana said: The halakhic status of a siman of which precisely half was cut and half remained uncut is not like that of a siman of which the majority was cut, and this is what the Merciful One said to Moses: Cut the majority of the siman. Therefore, cutting precisely half is insufficient.

The Gemara provides a mnemonic for the proofs that it cites with regard to this dispute: Half, Ketina, windpipe, deficiency.

We learned in the mishna: If one cut half of one siman in a bird or one and a half simanim in an animal, his slaughter is not valid. The Gemara questions the opinion of Rav: If you say that the halakhic status of a siman of which precisely half was cut and half remained uncut is like that of a siman of which the majority was cut, why is his slaughter not valid? By cutting half, didn’t he perform the cutting of a majority of the siman? The Gemara rejects that proof: By rabbinic law, the slaughter is not valid, due to the concern that perhaps he will not come to perform cutting on even half of the siman.

Rav Ketina said: Come and hear proof contrary to Rav’s opinion from a baraita with regard to an impure earthenware vessel that is purified through being broken. If it is broken in two, the larger portion remains impure and the smaller portion is purified. If he divided it into two and they are seemingly equal halves, both are impure, because it is impossible to measure precisely in breaking an earthenware vessel and render both halves equal. Since it is impossible to determine which half is larger, both remain impure due to uncertainty.

The Gemara infers: But were it possible to measure precisely and divide it into equal halves, both would be pure. If, as Rav states, the halakhic status of half is like that of a majority, why are they pure? Go here, to one half of the vessel, and you will see that there is a majority and it should remain impure, and go there, to the other half, and you will see that there is a majority and it should remain impure.

Rav Pappa said in rejecting that proof: There are not two majorities in one vessel. Therefore, one cannot consider the halakhic status of half like that of a majority. By contrast, with regard to cutting the windpipe or gullet, the halakhic status of precisely half can be like that of a majority, as there is no other majority contradicting that status.

The Gemara suggests: Come and hear another proof contrary to Rav’s opinion from a baraita: If one cut half the windpipe and interrupted the slaughter