in a case of severe ritual impurity, i.e., when the carcass of a kosher bird renders one’s garments impure while it is in his throat, which does not render impure another item similar to it, i.e., a person who is rendered impure by the carcass does not render another man impure; shall you also say that there is no requirement of thought in the case of lenient impurity, i.e., when the carcass transmits impurity as food, which does render impure another item similar to it? Food that became impure transmits impurity to other food, albeit by rabbinic law.

Abaye said to Rava: But in that case, all the more so impurity as food should apply without thought. If severe impurity, i.e., the unique impurity of the carcass of a kosher bird, which is lenient in the sense that it does not render impure another item similar to it, nevertheless imparts impurity without thought, i.e., without one knowing what is in his throat, then with regard to lenient impurity, i.e., the carcass’s impurity as food, which is more severe in the sense that it renders impure another item similar to it, isn’t it logical that it should impart impurity without thought?

Rather, Rav Sheshet said that this is what the Rabbis, who replied to Rabbi Yoḥanan ben Nuri, are saying: No, if you said that thought is not required with regard to severe impurity, i.e., the carcass of a kosher bird in the throat, as it does not require contact with a liquid for it to be rendered susceptible to ritual impurity, shall you also say that thought is not required with regard to lenient impurity, i.e., its impurity as food, where it does require contact with a liquid for it to be rendered susceptible to ritual impurity?

The Gemara asks: And does the carcass of a kosher bird require contact with a liquid for it to be rendered susceptible to impurity as food? But didn’t we learn in a baraita: Three matters were stated with regard to the carcass of a kosher bird: In order for it to be susceptible to impurity as food, it requires a person’s intent to eat it; and it transmits impurity to garments by rendering one who swallows it ritually impure only when an olive-bulk of it is in the throat; and it does not require contact with a liquid for it to be rendered susceptible to ritual impurity?

The Gemara answers: Although it does not require contact with a creeping animal for it to be rendered susceptible to impurity, i.e., it is inherently impure, nevertheless it does require contact with water or another liquid for it to be rendered susceptible to ritual impurity.

The Gemara asks: What is different about being rendered susceptible to ritual impurity by contact with a creeping animal that it does not require this contact? This ruling is in accordance with that which the school of Rabbi Yishmael taught. If so, it should also not require contact with water or another liquid for it to be rendered susceptible to ritual impurity, likewise in accordance with that which the school of Rabbi Yishmael taught.

As the school of Rabbi Yishmael taught in a baraita: The verse states that seeds contract impurity from the carcass of a creeping animal only if they first come into contact with water: “And if any part of their carcass fall upon any sowing seed that is to be sown, it is pure. But if water be put upon the seed, and any part of their carcass fall thereon, it is impure unto you” (Leviticus 11:37–38). This passage teaches that as long as water did not fall on the seeds, they are not susceptible to ritual impurity. This halakha applies to all items similar to seeds.

Accordingly, just as seeds, which will never transmit impurity severe enough to transmit to humans, like any food, require contact with liquid to be rendered susceptible to impurity, so too, all items that will never transmit severe impurity require contact with liquid to be rendered susceptible to impurity. This excludes the carcass of a kosher bird, which will ultimately transmit impurity severe enough to be transmitted to a human, i.e., when it is in his throat, and therefore it does not require contact with liquid for it to be rendered susceptible to ritual impurity.

Rather, Rava said, and some say that it was Rav Pappa who said: The Rabbis’ rejection of Rabbi Yoḥanan ben Nuri’s a fortiori inference is not based on the specific halakha of impurity of food imparted by the carcass of a bird. Rather, they are referring to the fact that in general there is no item under the common name of severe impurity that requires contact with a liquid for it to be rendered susceptible to ritual impurity. By contrast, with regard to the common name of lenient impurity as food, in general the items in this category require contact with a liquid for them to be rendered susceptible to impurity, despite the fact that the particular case of the carcass of a kosher bird is an exception. Therefore, intent is required for lenient impurity even in the case of a carcass of a kosher bird.

§ Rava says: And Rabbi Yoḥanan concedes with regard to the obligation to tithe, that intent while the produce is attached to the ground is considered intent. Rava said: From where do I say that this is the halakha? It is as we learned in a mishna (Ma’asrot 3:9) that deals with the obligation to tithe: Savory, hyssop [veha’ezov], and thyme [vehakoranit], i.e., various types of hyssop plants, that were growing in a courtyard, are eaten by some people although they are not specifically intended for human consumption. Therefore, if they were protected by the owners, those owners are obligated to separate tithes from them.

The Gemara clarifies the mishna: What are the circumstances of this ruling? If we say that it is referring to a case where one initially planted them for human consumption, does it need to be said that there is an obligation to tithe if they are protected by the owners? It is clear that in such a situation the criteria for the obligation to tithe, i.e., that it is human food which is protected, have been met. Rather, is it not referring to a case where one initially planted them to be fed to an animal, and nevertheless the mishna teaches: If the owner reconsidered their designation and decided to use them for human consumption and they were protected by the owners, the owners are obligated to tithe them. This apparently indicates that intent while the produce is attached to the ground is considered intent.

Rav Ashi said that Rava’s proof is inconclusive, for the following reason: Here we are dealing with a courtyard where these various types of hyssop plants grew by themselves, and where they are unspecified, they are intended for human consumption. Therefore, they meet the first criteria for the obligation to tithe, as they are considered food. And the mishna addresses the second requirement, that the food must be protected, and this is what it is saying: If the courtyard protects its produce, the owners are obligated in tithes, and if not, they are exempt.

Rav Ashi raises a further objection to Rava’s explanation from a mishna (50a): Any food from which one is obligated to separate tithes becomes impure with the ritual impurity of food. But if it is so, as Rava claimed, that intent while the produce is attached to the ground is considered intent with respect to the obligation to tithe, despite the fact that it is not considered intent with regard to impurity, then the mishna’s blanket statement is inaccurate. Rav Ashi elaborates: After all, there are these endives that were initially planted in order to feed to an animal and later the owner reconsidered their designation and decided to use them for human consumption, from which one is obligated to separate tithe, but which do not become impure with the ritual impurity of food.

Rava said in response that this is what the mishna is saying: Any type of food from which one is obligated to separate tithe becomes impure with the ritual impurity of food. In other words, this is referring to types of food, not to all situations. It is possible for a particular circumstance to be an exception to this principle.

The Gemara adds that this too stands to reason, that the mishna is referring only to types of food, not situations, from the fact that the latter clause teaches (51b): With regard to any animal from which the owner is obligated to give the first shearing of its wool, he is obligated to have gifts of the priesthood taken from it, i.e., the foreleg, the jaw, and the maw, if it was slaughtered. And there are animals from which one is obligated to have gifts of the priesthood taken from it, but from which he is not obligated to give the first shearing.

And if it is so, that the principles of the mishna are all-inclusive, one can raise the following difficulty: But there is the specific case of an animal with a wound that will cause it to die within twelve months [tereifa], from which one is obligated to give the first shearing, but one is not obligated to have gifts of the priesthood taken from it, as it may not be eaten. This proves that Rava is correct, that the mishna is not referring to all circumstances, but only to general categories.

Ravina said, rejecting this proof: It is possible that the mishna is referring to all circumstances, and as for the difficulty with regard to a tereifa, one can say that in accordance with whose opinion is this mishna? It is in accordance with the opinion of Rabbi Shimon, as we learned in a baraita: Rabbi Shimon exempts the owner of a tereifa from the mitzva of the first shearing.

Rav Shimi bar Ashi said: Come and hear a proof from a baraita that the mishna is not referring to all circumstances, but only to general categories: With regard to one who declares his vineyard ownerless, and who arose the next morning and picked grapes from the vineyard before anyone else took possession of them, he is obligated in the mitzva of leaving for the poor individual fallen grapes [peret], and in the mitzva of leaving for them incompletely formed clusters of grapes [uve’olelot], and in the mitzva of forgotten clusters, and in pe’a. The Torah includes such cases in the phrase: “Leave them for the poor and for the stranger” (Leviticus 19:10, 23:22), which is written with regard to all these mitzvot. And he is exempt from the obligation to separate the tithe from the grapes. Since the vineyard is ownerless, there is no obligation to tithe the produce.

The Gemara explains the proof: But didn’t we learn in the mishna (50a): With regard to any produce from which one is obligated to designate pe’a, one is likewise obligated to separate tithes? Rather, must one not conclude from the mishna that Rava is correct in asserting that the mishna is teaching only principles with regard to each type of produce, but there are exceptions in certain circumstances? The Gemara answers that one should in fact conclude from the mishna that Rava is correct.

§ With regard to the obligations of pe’a and tithes, the Gemara notes that we learned in a mishna elsewhere (Pe’a 3:2): The Rabbis and Rabbi Akiva disagree with regard to a case where one harvested several separate patches in a field. Rabbi Akiva rules that each patch requires its own pe’a, whereas the Rabbis maintain that one pe’a is required for all of the patches. Nevertheless, the Rabbis concede to Rabbi Akiva in the case of one who sows dill or mustard in two or three separate locations in a single field, that he leaves pe’a for each and every one of these plots on its own, rather than one corner for all of them.