1) HALACHAH: DRINKING THE "MEI RAGLAYIM" OF A DONKEY
OPINIONS: Rav Sheshes was asked whether one is permitted to drink the Mei Raglayim of a donkey. The Gemara explains that perhaps the fact that the Mei Raglayim is thick and resembles milk is an indication that it was formed from the body of the animal and is forbidden. On the other hand, perhaps the Mei Raglayim is nothing more than water that the animal drank and expelled and thus is permitted. The fact that the Mei Raglayim is thick is due merely to the heat (and decay, as Rashi explains) of the animal's flesh.
(The CHAZON ISH (YD 12:6) explains that the reason it should be forbidden is not that the water that the animal drank became mixed with its body fluids, but rather that the water entered the body and merged with the body, becoming part of it. When it later exits the body, it is considered something that is "Yotzei Min ha'Tamei," something that emerges from a forbidden animal, which also is forbidden. On the other hand, perhaps the water does not become absorbed into the body, and thus it is like water that enters and exits and is permitted.)
In the Gemara's first version of his answer, Rav Sheshes replies that the Mishnah implies that since the Mei Raglayim emerges from a "Min" ("species") of non-Kosher animal, it is forbidden even though it was not actually absorbed into the animal. (See RASHI to 7b, DH mi'Tamei and DH v'Hachi Nami.)
In the Gemara's second version, Rav Sheshes replies that there never was any question about whether the Mei Raglayim of horses and camels is permitted. Such Mei Raglayim is unfit for human consumption and is never consumed, and thus it is not considered a food and is not prohibited. The question involves only the Mei Raglayim of a donkey. Since some people drink this liquid, and since it has medicinal properties (it is used to cure jaundice), perhaps it is considered a food and is thus prohibited. Rav Sheshes answers that it indeed is prohibited.
What is the Halachah with regard to the Mei Raglayim of a donkey?
(a) The RAMBAM (Hilchos Ma'achalos Asuros 4:20) rules that Mei Raglayim of a donkey is permitted to drink. The RA'AVAD disagrees, pointing out that the Gemara here clearly concludes that it is forbidden.
The MAGID MISHNEH explains the Rambam's position. The Rambam does not rule like Rav Sheshes because the Halachah follows the opinion that only what emerges from the flesh of the non-Kosher animal is forbidden; the Mei Raglayim does not emerge from the flesh, but rather it merely passes through the body. Proof for this ruling is the statement of Rav Huna (7b) that the "skin opposite the face" of a donkey is permitted, because it is "Pirsha b'Alma," it is like waste material that is not considered part of the donkey. RASHI (DH Or) explains that this "skin" is a form of placenta in which the donkey is born. It is apparent from here that the Halachah does not follow Rav Sheshes, who inferred from the Mishnah that even something that does not actually emerge from the flesh itself is also forbidden.
(b) Most Poskim, however, rule like Rav Sheshes that the Mei Raglayim of a donkey is forbidden.
HALACHAH: The SHULCHAN ARUCH (YD 81:1) cites both opinions. However, since he cites the stringent opinion first, this implies that he rules in accordance with that opinion (see SHACH, end of YD 242, Kitzur b'Hanhagos #5).
(end of YD 81:3) points out that the Gemara's discussion involves only the status of Kashrus of the Mei Raglayim. In practice, drinking Mei Raglayim is prohibited because of the Isur of "Bal Teshaktzu" (Vayikra 11:43, 20:25), the prohibition against engaging repulsive practices (see Insights to Makos 16:3
for a discussion of the nature of this Isur).
The Shach (YD 81:2) also writes that even a sick person is forbidden to drink the Mei Raglayim of a non-Kosher animal unless his life is in danger. The Shach asserts that it is clear from the Gemara that although some people (presumably Nochrim) drink the Mei Raglayim as a cure for jaundice (which apparently is not a life-threatening condition), a Jew is prohibited to do so. The Gemara mentions that some people drink the Mei Raglayim as a cure for jaundice only in order to prove that it has the status of a food and is fit for consumption (in contrast to the Mei Raglayim of horses and camels). Since the Gemara concludes that it is forbidden, it follows that it is forbidden even in order to cure jaundice.
However, the Shach cites the BACH who quotes the MORDECHAI (Shabbos #383) who rules that a sick person whose life is not in danger is permitted to drink the Mei Raglayim of a donkey. The Shach points out that the Mordechai there actually says that "since some people drink it for jaundice, it is [considered a food and thus is] forbidden."
The PRI MEGADIM (Sifsei Da'as 81:2) refutes the Shach's proof from the Gemara that drinking the Mei Raglayim of a donkey to cure jaundice is forbidden. Perhaps when the Gemara says that some people drink it for jaundice and then says that it is forbidden, the Gemara means that some people drink it as a preventative measure against contracting jaundice. This is implied by the words, "u'Ma'alu l'Yarkona," which mean, "and it is good (healthy) for jaundice," suggesting that healthy people drink it as a preventative measure. It might be permitted, however, to drink it in order to cure jaundice. (See also Sifsei Da'as YD 103:2, and CHAZON ISH YD 12:6, DH v'Ha.) (D. BLOOM)
2) HALACHAH: A NON-KOSHER FISH FOUND INSIDE A KOSHER FISH
QUESTION: The Mishnah states that when a Kosher fish swallows a non-Kosher fish, the non-Kosher fish remains forbidden to be eaten.
TOSFOS (DH Dag Tahor) asks that the Mishnah in Ohalos (11:7) teaches that when a bird or fish eats a k'Zayis of flesh from a dead person, the flesh inside of the bird or fish is no longer Tamei once enough time passes such that had the flesh fallen into a fire, it would have been completely destroyed. In that amount of time, the flesh becomes digested and no longer exists. Accordingly, the non-Kosher fish that was swallowed by the Kosher fish should also become nullified by being digested in the stomach of the Kosher fish.
(a) TOSFOS answers that while digestion nullifies Tum'ah, it cannot nullify an Isur.
(b) RABEINU TAM cited by Tosfos explains that the Mishnah in Ohalos is expressing the view of Rebbi Shimon. Rebbi Yehudah ben Beseirah argues and says that a 24-hour period is required for digestion. The Mishnah here is expressing the view of Rebbi Yehudah ben Beseirah, and it is discussing a case in which the 24-hour time period for digestion has not passed.
(c) The ROSH quotes RABEINU MOSHE of Pontoise who answers that food is considered digested only when it has been chewed. If it was swallowed whole, then it is not considered to be digested.
HALACHAH: Tosfos points out that this issue has additional practical relevance. What is the Halachah in a case in which a chicken is slaughtered and cooked on Pesach, and a grain of wheat is found in the stomach of the cooked chicken? According to the first answer of Tosfos, the chicken is forbidden. According to the second answer, if the time period for digestion has passed, the chicken is permitted.
The SHULCHAN ARUCH (YD 83:10) writes that a non-Kosher fish found inside a Kosher fish is forbidden, and he makes no distinction between whether the time for digestion has passed or not. He apparently follows the view of the first answer of Tosfos.
3) HALACHAH: A KOSHER FISH FOUND INSIDE A NON-KOSHER FISH
QUESTION: The Mishnah states that when a non-Kosher fish swallows a Kosher fish, the Kosher fish remains permitted to be eaten.
Why is the Kosher fish, inside the non-Kosher fish, not forbidden because of the rule of "Yotzei Min ha'Tamei" -- anything that comes from a non-Kosher animal is also not Kosher? This rule prohibits the urine of a non-Kosher animal, even though it is nothing more than water that has passed through the animal's body, as Rav Sheshes rules earlier. (TOSFOS DH Rov)
(a) TOSFOS explains that secretions of a non-Kosher animal (which are not produced by the animal but simply pass through it) become prohibited only when they leave the body of the animal. This fish was found inside of a non-Kosher fish, and it never was discharged by the host fish.
(b) Tosfos answers further that the Kosher fish certainly has no physical connection at all to the non-Kosher fish in which it was found. Rather, just as it entered, it left. In contrast, excretions such as urine pick up fluids from the body of the non-Kosher animal, and it is these fluids that prohibit the urine.
HALACHAH: The Halachah follows the view of Rav Ashi, who rules that even when one did not see the non-Kosher fish swallow the Kosher fish, it may be eaten, because we assume that the reason why the Kosher fish is inside of the non-Kosher fish is that it was eaten, and not that it grew there. Since most fish breed their own type, it is unlikely that the Kosher fish was bred by the non-Kosher fish. This is the way TOSFOS, the ROSH, and the SHULCHAN ARUCH (YD 83:9) rule.
The SHACH (YD 83:9) permits the fish even when it is found inside the womb of the non-Kosher fish (which indicates that it was bred by the non-Kosher fish). However, the TAZ and PRI CHADASH forbid the fish in such a case, because its presence in the womb indicates that the non-Kosher fish produced it; it is not possible to get inside the womb through the digestive tract.