PAST DEDICATION
BAVA KAMA 21-25 - Two weeks of study material have been dedicated by Mrs. Estanne Abraham Fawer to honor the ninth Yahrzeit of her father, Rav Mordechai ben Eliezer Zvi (Rabbi Morton Weiner) Z'L, who passed away on 18 Teves 5760. May the merit of supporting and advancing Dafyomi study -- which was so important to him -- during the weeks of his Yahrzeit serve as an Iluy for his Neshamah.

1) THE DIFFERENCE BETWEEN THE VIEWS OF REBBI YOCHANAN AND REISH LAKISH WITH REGARD TO "ESH"
QUESTION: The Gemara concludes that even Rebbi Yochanan, who says "Isho Mishum Chitzav," agrees that Esh is also considered "Mamono." Therefore, according to Rebbi Yochanan, when one lights a fire in a walled area, and the wall falls down by itself and the fire spreads to another field and burns grain because the owner was negligent and did not rebuild the wall, the owner of the fire is exempt for damage done to Tamun (items that were hidden). In such a case the fire is not considered Adam ha'Mazik, and yet he is still liable to pay for the field because of "Isho Mishum Mamono."
The Gemara asks that if Rebbi Yochanan agrees that "Isho Mishum Mamono," what is the practical difference between the view of Reish Lakish who says that Esh is only "Mishum Mamono" and the view of Rebbi Yochanan who says that Esh is also "Mishum Chitzav"? The Gemara answers that the difference is whether the person is liable for Arba'ah Devarim. According to Rebbi Yochanan, a person must pay compensation of Tza'ar, Ripuy, and Sheves for damage that his fire does to another person because his fire is considered like Adam ha'Mazik (in a manner that is "Karov l'Mezid"; see Rashi to 27a, DH v'Niska; RABEINU CHANANEL writes that the one who lit the fire is also liable to pay compensation of Boshes according to Rebbi Yochanan, since he is considered like a person who caused damage with full intent, completely "b'Mezid").
Why does the Gemara ask what the difference is between Rebbi Yochanan and Reish Lakish? The Gemara in the previous Sugya (22b) has already mentioned a number of differences, such as when a person's animal takes someone else's fire and causes it to burn a field. According to Rebbi Yochanan, the owner of the animal pays Chatzi Nezek for the damage done to the entire field, and according to Reish Lakish the owner of the animal is exempt for the damage done to the field (see Rashi, DH v'Chi me'Achar).
Also, if a person lights a fire that burns a bound slave, Rebbi Yochanan maintains that the one who lit the fire is Chayav Misah, since he is considered as though he killed the person directly, while Reish Lakish exempts him from Misah since he did not kill the person directly.
A more difficult problem is why the Gemara does not mention the practical difference that it mentions just one line earlier. According to Rebbi Yochanan, one usually is Chayav when his Esh burns something that is Tamun, since it is like Adam ha'Mazik (unless the fire is lit in a walled area and the wall fell down on its own after the fire was lit, as mentioned above). According to Reish Lakish, one is always exempt for Esh that burns Tamun since it is never considered "Chitzav." (TOSFOS DH Mai Beinaihu)
ANSWERS:
(a) TOSFOS answers that the Gemara indeed could have suggested these differences, but it chose to mention only one difference.
This answer is difficult to understand, especially with regard to the difference which the Gemara has just discussed. Why should the Gemara search for another difference between Rebbi Yochanan and Reish Lakish when it is in the middle of discussing one? (BI'UR HA'GRA CM 418:33)
Perhaps Tosfos means what the RA'AVAD, RASHBA, and RI MI'GASH write (as cited by the Shitah Mekubetzes). The Gemara is seeking an additional practical difference, besides the ones mentioned earlier in the Gemara. (This answer, too, is somewhat forced in the wording of the Gemara.)
RABEINU YEHONASAN and the RI MI'GASH add that the difference that the Gemara here suggests has much broader applications than the differences of Tamun and burning something with another person's fire, since it theoretically could apply to any fire that was lit and not just to certain fires in specific cases.
(b) RASHI here answers that the words of Rebbi Yochanan, "Isho Mishum Chitzav," imply that he argues with Reish Lakish even in the case of a fire that belongs to the person who started it. That is why the Gemara does not use the difference of the dog that took someone else's coal and started a fire with it.
Rashi does not address the differences of Tamun and of killing a person with one's fire. How does Rashi answer why the Gemara does not mention those differences when it asks for the practical difference between Rebbi Yochanan and Reish Lakish?
Perhaps, according to Rashi, the Gemara does not give the difference of Tamun since it is looking for a case in which Rebbi Yochanan and Reish Lakish argue about all of the damage that the fire caused. In the case of Tamun, they agree that one is obligated to pay for the wheat that hid the object, and they agree that one is obligated even to pay for the object that was hidden, as though it were wheat. The argument in such a case is only whether one pays the full value of the object that was Tamun.
The Gemara does not mention the difference of being Chayav Misah for killing the Eved (see MAHARAM SHIF) because the Gemara wants to find a difference with regard to the laws of monetary damages and obligations (Nizkei Mamon), since Rebbi Yochanan and Reish Lakish are discussing the damage of Esh of the Mishnah, which is a case of monetary damage. (TALMID RABEINU TAM V'RABEINU ELIEZER)
(c) RABEINU PERETZ answers that the Gemara wants to find a difference between Rebbi Yochanan and Reish Lakish with regard to the case of Esh that is discussed in the Torah ("Ki Setzei Esh...," Shemos 22:5). The Esh of the verse refers to a person's own Esh that he lit. Furthermore, it does not discuss Chiyuvei Misah. Also, it does not discuss Tamun, since one is exempt for damages to Tamun. Therefore, the Gemara gives the difference of Arba'ah Devarim, which applies to the Esh that the Torah discusses according to Rebbi Yochanan but does not apply to the Esh that the Torah discusses according to Reish Lakish.
(d) The RAMBAM (Hilchos Nizkei Mamon 14:15) seems to take a different approach to the Sugya. The Rambam rules like Rebbi Yochanan and writes that although one is liable for Esh "Mishum Mamono," it is also considered as though one was Mazik directly, with his "Chitzav," meaning that Esh is considered both "Mamono" and "Chitzav."
The MAGID MISHNEH asks that if the Rambam rules like Rebbi Yochanan, why does he write (Hilchos Nizkei Mamon 14:8-9) unequivocally that a person is exempt for damages of Tamun caused by Esh? The Gemara says that according to Rebbi Yochanan, a person is exempt from Tamun only in a case where he lit the fire in a walled area and then the wall collapsed by itself, and the fire went to another field and damaged items that were Tamun!
The Magid Mishneh concludes that the Rambam must have learned the Gemara differently, or that he preferred to explain all of the Mishnayos which exempt one from damages of Tamun in their most straightforward sense.
The VILNA GA'ON favors the first suggestion of the Magid Mishneh. The Rambam learned the Gemara's question differently from the other Rishonim.
The other Rishonim explain that if lighting a fire is tantamount to shooting an arrow, the Torah would not exempt one for damage done by fire to objects that are Tamun, just as it does not exempt one from damage done to objects that are Tamun that one damages directly with his hands. However, the Rishonim ask, why does the Gemara assume that the Torah does not exempt one from damages of fire to Tamun if "Isho Mishum Chitzav"? The Gemara derives that one is exempt for damage done by fire to Tamun from an inference in the verse (see 60a). Even if Adam ha'Mazik is liable for Tamun, the verse exempts one from damages of Esh to Tamun! (TOSFOS HA'ROSH, RASHBA; see TOSFOS DH Tamun.)
Moreover, the Vilna Ga'on asks, why does the Gemara ask "where do we find a case of Tamun for which one is exempt [according to Rebbi Yochanan]?" The Gemara should have phrased its question, "Why is one exempt for Tamun [according to Rebbi Yochanan]?"
Based on these questions, the Vilna Ga'on explains that the Rambam understood the Gemara differently. The Gemara (61b) teaches that when a person lights a fire in someone else's field, he is not exempt for all items that are Tamun in the field. He is exempt only from paying for anything that is Tamun when he lights the fire in his own field and the fire spreads to someone else's field. The Gemara's question here is that if lighting a fire is like shooting an arrow, then whenever the fire causes damage in another's field it should be as if the person placed the fire in the other field directly, and he should be Chayav for Tamun! When the Gemara concludes that Rebbi Yochanan agrees that Esh is also "Mishum Mamono," it means that with regard to this particular point, even though Esh is like shooting an arrow it cannot be considered as though he lit the fire in the other person's field, but rather it is like property of his that wandered into another person's field by itself. The reason for this is that even after the fire is lit the person can enclose his field with a fence such that the fire will not spread to the other person's field.
However, this difference between fire and an arrow applies only with regard to the exemption of Tamun (because of the Gezeiras ha'Kasuv that teaches that one is exempt for Tamun). With regard to the liability for Arba'ah Devarim (and for the Chiyuv Misah for killing someone), the one who lit the fire is liable just as one who shoots an arrow at someone, according to Rebbi Yochanan.
This answers why the Gemara does not give Tamun as the difference between Rebbi Yochanan and Reish Lakish. It does not give Tamun as the difference because Rebbi Yochanan indeed exempts one from all cases of Tamun damaged by Esh.
(e) According to Rashi's first Lashon, all of these questions may be answered in a simple way. See following Insight.
2) ONE WHO DAMAGES WITH A FIRE THAT IS NOT HIS
QUESTIONS: The Gemara concludes that even Rebbi Yochanan, who says "Isho Mishum Chitzav," agrees that when the fire that a person lit cannot be compared to an arrow the owner will be liable because Esh is also "Mamono." The Gemara asks that if Rebbi Yochanan agrees with Reish Lakish that "Isho Mishum Mamono," what is the difference between the views of Rebbi Yochanan and Reish Lakish (see previous Insight)?
RASHI explains the Gemara's question at length. There are a number of problems with Rashi's explanation in this Sugya.
(a) RASHI (22a, DH Mishum Mamono) writes that the Gemara "originally thought" that Rebbi Yochanan and Reish Lakish argue with regard to a fire that does not belong to the person who caused it to destroy someone's field. Why does he write that this was the Gemara's "original" assumption? Rashi himself writes here that even in the Gemara's conclusion, Rebbi Yochanan and Reish Lakish argue about such a case! (MAHARAM to 22a, SHITAH MEKUBETZES to 22a and 23a in the name of GILYON, NIMUKEI YOSEF; see also MAHADURA BASRA of MAHARSHA, PNEI YEHOSHUA, and NACHALAS DAVID.)
(b) Rashi here explains that Rebbi Yochanan uses the word "Isho" ("his fire," as opposed to "Esh," "[anyone's] fire") because he refers specifically to a fire that belongs to the person who caused the damage. However, Rashi earlier (22a, DH Mishum Mamono) explains that Rebbi Yochanan refers to a person who causes damage with a fire that does not belong to him! (NETZIV in Meromei Sadeh)
(c) Rashi (beginning of DH Mai Beinaihu) explains why the Gemara does not suggest that the difference between Rebbi Yochanan and Reish Lakish is a case in which the fire did not belong to the person who caused it to do damage. Later, however, Rashi (end of DH l'Chayavo) again asks why the Gemara does not give as a difference the case of a fire that did not belong to the person who caused it to do damage! (LECHEM ABIRIM)
(d) What does Rashi mean when he concludes (in DH l'Chayavo) that he prefers the "Lashon Rishon," the first Lashon? Rashi makes no mention of two Leshonos!
ANSWERS: The MAHARAM points out that the MAHARSHAL (in Yam Shel Shlomo) quotes a version of Rashi in which Rashi indeed presents two different Leshonos. These two Leshonos are also quoted by RABEINU YESHAYAH in the Shitah Mekubetzes and by the CHIDUSHEI HA'RA'AVAD. The first Lashon of Rashi was that Rebbi Yochanan obligates one only for Esh "Mishum Chitzav" in a case where the fire belongs to the one who caused it to do damage. If the fire does not belong to him, the fire is not considered "Chitzav." According to this understanding, Rebbi Yochanan does not literally compare a fire to shooting an arrow, and in the case of a fire that is not his -- or when someone kills another person with a fire -- Rebbi Yochanan exempts the one who lit the fire, just as Reish Lakish exempts him. Also, Rebbi Yochanan exempts a person from liability for damage done with fire to Tamun, since such damage is not literally like Adam ha'Mazik. It is similar to "Chitzav" only with regard to paying Arba'ah Devarim (that is, with regard to Arba'ah Devarim it is considered as though the person did the damage directly). The reason why Rebbi Yochanan rules that one is liable for Arba'ah Devarim even though Esh is not considered Adam ha'Mazik in any other way is that the verse which writes the word "ha'Mav'ir" (Shemos 22:5) implies that there is at least one way in which lighting a fire is comparable to Adam ha'Mazik, to a person who damages directly.
This approach answers all of the questions posed in the previous Insight as well as the questions asked on Rashi here.
(a) Rashi (22a) writes that the Gemara "originally thought" that Rebbi Yochanan obligates a person to pay for damages that he caused with a fire that does not belong to him. Those words are from Rashi's first Lashon, in which he learned that Rebbi Yochanan -- according to the Gemara's conclusion -- does not obligate one to pay unless the Gacheles belongs to the person who damages with it. (MAHARAM)
(b) The reason why Rashi there writes that Rebbi Yochanan is not necessarily discussing a fire that belongs to the person who damaged with it is that, according to Rashi's first Lashon, even if Rebbi Yochanan is discussing a fire that was not owned by the person who damaged with it, there is a good reason why the Gemara does not give such a case as the difference between Rebbi Yochanan and Reish Lakish. The Gemara's conclusion is that Rebbi Yochanan and Reish Lakish do not argue about such a case, since Rebbi Yochanan agrees that "Isho Mishum Mamono" as well.
(c) Apparently, Rashi added his second explanation (the explanation which appears in Rashi DH l'Chayavo) as an alternative approach ("Lishna Acharina") to the Gemara. At that point, Rashi did not yet fully accept the suggestion that Rebbi Yochanan's use of the word "Isho" implies that he is discussing a case of a fire owned by the person who caused the damage with it. That is why Rashi preferred the first approach, wherein Rebbi Yochanan and Reish Lakish do not argue about an Esh that does not belong to the person who damages with it. (This indeed is the way Rashi's commentary appears in the London and Parma manuscripts.) Later, Rashi decided that it was the more correct approach and that the original approach was incorrect, and he removed his first Lashon (which no longer appears in our text of Rashi) and he rewrote his commentary to the Gemara in accordance with his second, new explanation. It was at that point that he added what he wrote in DH v'Chi Me'achar. (Indeed, the London and Parma manuscripts of Rashi omit his comment of DH v'Chi Me'achar, and in the Rome manuscript, Rashi's comments in DH v'Chi Me'achar are written in a marginal addition.) Our text of Rashi was copied from both the new version of Rashi (the marginal addition in the Rome manuscript) and the old version of Rashi (the London and Parma manuscripts). That is why, in our text, Rashi repeats part of his commentary about "Isho." (A similar combination may be found in the Cambridge manuscript of Rashi.)
(d) When Rashi wrote that "the first Lashon seems correct to me," he was referring to the first Lashon which no longer appears in our text because Rashi retracted it in favor of the second Lashon, the Lashon that does appear in our text. (Rashi removed, as well, these words of "Lashon Rishon Nir'eh Li," but these words were included in our text by the scribes who copied Rashi's words from his Mahadura Kama. Indeed, these words are omitted in the Cambridge manuscript of Rashi, which includes Rashi's final explanation -- the version which appears in our text of Rashi.)
(The manuscript versions of Rashi are printed in Rav Shabse Frankel's SEFER SHINUYEI NUSCHA'OS.)

23b----------------------------------------23b

3) THE MOUTH OF AN ANIMAL
QUESTION: The Gemara proves that the Mishnah discusses the case of a dog that takes a Chararah and eats it in the Chatzer of the owner of the Chararah. The Mishnah teaches that the owner of the dog must pay for the Chararah because the damage done by the dog is Shen in the domain of the Nizak. The Gemara attempts to prove from here that the mouth of an animal is considered like the Chatzer of the Nizak, in which the animal is standing, and not like the Chatzer of the Mazik who owns the dog. If it would be considered like the Chatzer ha'Mazik, the owner of the dog should not be liable in the case of the Mishnah; he should be able to say to the owner of the Chararah, "What is your Chararah doing in my dog's mouth?"
The Gemara questions how the mouth of an animal can be considered Chatzer ha'Mazik. If it would be considered Chatzer ha'Mazik, how would one ever be liable for damages of Shen? The Gemara answers that one would be liable for Shen only when the animal damages by causing an object to be consumed without putting it in its mouth (for example, by rubbing its back on a wall and rubbing away the pictures inscribed on the wall, or by rubbing itself on fruits until they are irretrievably lost in the mud).
Why does the Gemara wait until this Mishnah to discuss whether the mouth of an animal is like Chatzer ha'Mazik or Chatzer ha'Nizak? If the mouth of an animal is not like Chatzer ha'Nizak, one should never be liable for Shen when an animal eats someone else's fruit! The Gemara should be able to prove that the mouth of an animal is like Chatzer ha'Nizak from any of the previous Mishnayos (such as 19b) which mention eating fruit as a description of the damage of Shen.
Moreover, how can the Mazik complain to the Nizak, "What is your Chararah doing in my dog's mouth," if his dog entered the Nizak's domain without permission?
ANSWERS:
(a) The TOSFOS HA'ROSH and TOSFOS RABEINU PERETZ explain that the Gemara originally assumes that one is liable for Shen even when the fruit was not eaten in Reshus ha'Nizak, as long as it was taken from Reshus ha'Nizak. Therefore, even if the mouth of an animal is like the Chatzer ha'Mazik, the owner of the dog will be liable since his dog took the food from Reshus ha'Nizak.
What, then, is the question of whether the mouth of an animal is like Reshus ha'Nizak? The question would arise in a case where the dog did not take the food from Reshus ha'Nizak, but rather the food was taken by a Cheresh, Shoteh, Katan, or Nochri from the Reshus ha'Nizak and placed into the dog's mouth. (The RASHBA cites the RA'AVAD who suggests that the question would arise in a case where the animal took the food from a third party's Reshus ha'Yachid, and then it ate it in the Reshus of the Nizak.)
If this, however, is the question, then how can the Gemara prove from the Mishnah that discusses a dog that took a Chararah that the mouth of an animal is like the Chatzer ha'Nizak? In the case of the Mishnah, the dog took the Chararah by itself, and thus the owner is certainly liable because the Chararah was taken from the Reshus of the Nizak by his animal!
Tosfos explains that the Gemara's proof is not from the Mishnah but from the short Sugya that precedes this point of the Gemara. The Gemara asks, why is the owner of the dog liable if the dog ate the Chararah in any place other than the Reshus ha'Nizak? The Gemara concludes that the dog indeed ate the Chararah in the Reshus ha'Nizak. From this Sugya it is clear that it does not suffice for the dog to take the Chararah from the Reshus ha'Nizak, but it must also eat the Chararah in the Reshus ha'Nizak in order for the dog's owner to be liable. Thus it is clear that the mouth of the animal is like the Chatzer ha'Nizak.
According to this explanation, the Mishnayos which describe Shen as an animal that eats food in the Reshus ha'Nizak do not prove that the mouth of an animal is like the Chatzer ha'Nizak, since they are discussing an animal that takes the food from the domain of the Nizak. Why does the Gemara ask when will one be liable for Shen if the mouth of an animal is like the Chatzer ha'Mazik? One will be liable for Shen when the animal takes the food by itself directly from the Reshus ha'Nizak, in which case it makes no difference where it eats the food! Tosfos answers that the verse implies that the animal not only takes the food from Reshus ha'Nizak but even eats it there as well. Therefore, the Gemara asks that if the mouth of an animal is considered the Chatzer ha'Mazik, how is one to understand the verse that implies that the owner is liable for Shen when the food is consumed in the Chatzer ha'Nizak.
(b) RABEINU YESHAYAH in the Shitah Mekubetzes explains that the Gemara knows that if one sends his animal into another's Reshus, he is liable even if his animal eats the food in a different Reshus. The question is whether he is liable when the animal goes by itself into another's Reshus. The Gemara proves that one is liable even if the animal goes by itself, because its mouth is like the Chatzer ha'Nizak, from the fact that one is liable when one's dog eats the Chararah (as the Mishnah says). The Mishnah refers to a case in which the dog went by itself and ate the Chararah, as the Mishnah says, "a dog that took a Chararah...." This is clear from the Gemara which requires that the dog eat the Chararah in the Reshus of the owner of the Chararah in order for the dog's owner to be liable. (If the owner had sent the dog there, he would have been liable regardless of where the dog eats the Chararah, according to Rabeinu Yeshayah.)
When the Gemara asks that if the mouth of the dog is like the Chatzer ha'Mazik, then in what case does the Torah obligate one for damages of Shen, it knows that one would be liable for Shen when he sends his dog into the Chatzer ha'Nizak. The Gemara's question was, as explained earlier (3a), that the Torah obligates him even when he does not send the dog into the Chatzer ha'Nizak but it goes by itself. How, though, can one be liable in that case if the dog's mouth is like Chatzer ha'Mazik? That is the Gemara's question.
The RASHBA cites the RA'AVAD who offers a similar explanation. The Gemara knows that when the animal picks up the food in the Chatzer ha'Nizak, the owner is liable even if the animal eats the food in a different Reshus. The question is whether the owner is liable when the animal takes the food from the Reshus of a different person (who does not own the food) and eats it in the Reshus of the owner of the food. If the mouth of the animal is like Chatzer ha'Nizak, one is liable, but if it is not, one is not liable. The Gemara proves that one is liable when his animal takes the food from a Reshus that belongs to someone other than the owner of the food and eats it in the Reshus of the food's owner (because its mouth is like the Chatzer ha'Nizak) from the fact that one is liable when one's dog eats the Chararah (as the Mishnah says). The Mishnah refers to a case in which the dog took the Chararah from the Reshus of a different person and ate the Chararah in the Reshus of the owner of the Chararah, as the Mishnah says, "A dog that took a Chararah and went to a Gadish and ate [the Chararah there]." This is clear from the Gemara which requires that the dog eat the Chararah in the Reshus of the owner of the Chararah in order for the dog's owner to be liable. (If the dog had taken the Chararah from the Reshus of the owner of the Chararah, the owner of the dog would have been liable regardless of where the dog eats the Chararah, according to the Ra'avad.)
(This interpretation of the Mishnah answers the first question of TOSFOS DH v'Lechayav, and this might be the intention of RASHI DH Hachi Garsinan and DH v'Lechayav, unlike the BACH #2.)
According to the Ra'avad, when the Gemara asks how is one ever liable for Shen, the Gemara does not know that one certainly is liable when the animal takes the food from the Reshus of the food's owner. The Gemara answers its question according to the understanding of the questioner.
The difference between Tosfos' explanation (in (a) above) and the explanation of Rabeinu Yeshayah and the Ra'avad is that according to Tosfos, the Gemara concludes that in order for its owner to be liable, the animal must both take the food and eat the food in the Reshus of the Nizak. According to Rabeinu Yeshayah and the Ra'avad, this is not true; the owner could be liable if the animal only takes the food from the Reshus of the Nizak and does not eat it there, when the owner sends the animal there to eat it (Rabeinu Yeshayah), or when the animal takes the food from the Reshus of the Nizak (Ra'avad). (See TOSFOS to 20a, DH Misgalgel.)
(c) The RADVAZ cited by the Shitah Mekubetzes and the MAHARACH OR ZARU'A (#109) explain that the question of the status of the animal's mouth applies only when the Nizak does not properly protect his fruit from coming into the mouth of the animal. For example, the Gemara teaches (23a) that the owner of the Chararah did not protect his Chararah properly from dogs, since dogs are known to dig under gates (see TOSFOS DH b'she'Shimer). In such a case, the owner of the animal has a valid claim when he says, "What is your food doing in my animal's mouth?" What he means is that the Nizak should have protected his food from coming into the mouth of the animal of the Mazik. On the other hand, perhaps the mouth of the animal is considered like the Chatzer ha'Nizak, meaning that the Nizak is not responsible for keeping his food out of the Mazik's animal as long as the food is in the Nizak's Reshus.
The Gemara's proof that the mouth of the animal is like the Chatzer ha'Nizak is from the Mishnah which says that the owner of the dog is liable to pay for the Chararah even though the Chararah was not properly protected from dogs. When the Gemara asks how can one be liable for Shen in Reshus ha'Nizak if the mouth of an animal is like Reshus ha'Mazik, the Radvaz explains that the question is that most fields are not properly guarded to prevent animals from entering, and therefore the verse seems to obligate the owner of the animal even if the Nizak does not take proper care to keep the animal out. (The Maharach Or Zaru'a explains that the proof is from Shen b'Reshus ha'Rabim, in which case the Torah teaches that Shen is exempt. Why does the Torah need to teach that Shen is exempt in Reshus ha'Rabim? In any case Shen should be exempt there because the Nizak -- who placed his food in Reshus ha'Rabim -- did not take care to keep it out of the mouth of the Mazik's animal!)
(d) The TOSFOS RID and RASHI seem to explain the Gemara in its most straightforward sense, that if the mouth of an animal is like Reshus ha'Mazik, one is never liable for what one's animal eats. They may understand that whenever the word "Achlah" appears in the Mishnah in reference to Shen, it does not refer to consumption through eating but rather to consumption through other means (such as rubbing off inscriptions from walls). The Mishnah, which discusses a dog which takes a Chararah in its mouth and then eats it, implies that even if the animal literally eats it the owner is liable.

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