1) IS AN EGG CONSIDERED PART OF THE HEN?
QUESTION: The Gemara says that an egg inside a hen that becomes a Tereifah is forbidden to be eaten as well. The egg is considered part of the hen's body ("Ubar Yerech Imo Hu"), and thus it has the same Halachic status as the mother.
TOSFOS (DH v'Hilchesa) asks that the Gemara here seems to contradict the Gemara in Bava Kama (47a). The Gemara there discusses a case of an animal or hen that causes damage. The Halachah is that the one who is damaged is allowed to collect compensation only from the value of the body of the damaging entity (that is, when the animal is a "Tam" that has not gored three or more times, in which case the payment for the damages is taken from the animal itself, "mi'Gufo"; see RASHI to Bava Kama 47a, DH Leisa l'Parah). The Gemara quotes Rabah who says that when a pregnant cow damages, the victim may collect compensation from the value of the cow's fetus as well, since it is considered part of the body of the mother. However, the Gemara there says that when a "pregnant" hen damages, one may not collect from its egg, since the egg is considered something that merely comes out of the hen and is not a part of it. The Gemara there clearly implies that an egg is not considered part of the hen at all. How are these two Gemaras to be reconciled?
ANSWERS:
(a) TOSFOS answers that the Gemara in Bava Kama is discussing a case in which the egg had already finished developing. At this point, it is no longer considered part of the hen. Even if the egg's state of development at the time the hen is damaged is uncertain, the owner may tell the claimant that the burden of proof is upon him to prove that the eggs were part of the mother at the time of the damage. However, Tosfos says, in the case of a hen that is a Tereifah, its eggs are forbidden. Tosfos in Bava Kama (47a, DH Mai Taima) explains that the only eggs that are forbidden according to Torah law are eggs that were in their early stages of development (that is, they were still intermingled with sinews) when the hen became a Tereifah. However, mid'Rabanan, all eggs of a Tereifah are forbidden. Hence, even if the hen lays a fully developed egg immediately after it becomes a Tereifah, a Gezeirah d'Rabanan prohibits the egg.
In a similar vein, the SHITAH MEKUBETZES quotes some who say that the Gemara in Bava Kama is correct when it states that an egg is not considered part of the mother, and thus the prohibition of an egg of a Tereifah hen is mid'Rabanan, in most cases. However, at the very beginning of the egg's development (when it is totally enwrapped in sinews), it is considered part of the mother hen. Consequently, if a hen was a Tereifah at the beginning of the egg's development, then the egg would be Asur mid'Oraisa. Although this is not likely to happen (since a hen that is a Tereifah usually cannot produce eggs), the Rabanan were strict and prohibited any egg that comes out of a hen that became a Tereifah, even if it became a Tereifah immediately before laying the egg, in order to safeguard the Torah's prohibition.
(b) The Shitah Mekubetzes quotes RABEINU ELCHANAN who explains that the Gemara here is also discussing an egg that has finished developing, and nevertheless it is considered a Tereifah. This is because an egg which has no life of its own is considered part of the mother even when it is fully developed, because its connection to life depends on its mother. The Gemara in Bava Kama, in contrast, is concerned with whether an egg is a physical part of the hen. Only an animal fetus is considered part of the mother, as opposed to an egg which is merely something that comes out of the mother. It is possible that Rabeinu Elchanan means that since an egg has a separate shell that develops around it, it is not considered part of the mother, even though its existence is dependent on the mother hen. This is in contrast to an animal, which is directly connected to its mother when in the womb, and therefore is considered a physical part of its mother. (Y. MONTROSE)
2) THE EGGS ARE LIKE THE HEN
QUESTION: According to the Gemara's first version of Ameimar's statement, an egg inside a hen that becomes a Tereifah is forbidden to be eaten as well. The egg is considered part of the hen's body ("Ubar Yerech Imo Hu"), and thus it has the same Halachic status as the mother. If, however, the hen mated with a rooster that contributed to the development of the egg, the egg is permitted because "Zeh v'Zeh Gorem" is Mutar.
If the egg is considered part of the hen's body, then what difference does it make if the rooster contributed to its development? Since it is attached to a Tereifah hen, the egg should be prohibited. Even though there is a rule that "Zeh v'Zeh Gorem" is Mutar, that rule should remove only the prohibition that comes from being born to a prohibited hen. However, that rule should not remove the prohibition that comes as a result of being part of a prohibited hen. (See RASHASH and TIFERES YAKOV. Although TOSFOS (DH v'Rebbi Eliezer) cites a different Girsa that says that the egg indeed is a Tereifah even if it came into existence after the mother became a Tereifah, both Tosfos and Rashi reject this Girsa.)
ANSWERS:
(a) The AVNEI NEZER (YD 23, cited by the YOSEF DA'AS here) writes that there are two ways to understand the cause of the Isur of Tereifah. The Isur of Tereifah can result from the fact that the animal presently suffers a mortal wound. The Isur also can result from the fact that an act occurred to the animal that created a mortal wound. The Avnei Nezer suggests that the Gemara here implies that an Isur Tereifah is caused by the fact that an act occurred to the animal that caused a mortal wound. In the case of an egg inside of a Tereifah hen, no act occurred to wound the egg itself, and thus the egg itself is not considered a Tereifah. The only reason to prohibit the egg is that it came into existence through a Tereifah hen. However, when it came into existence through both a hen and a rooster, it is not prohibited, since it came into existence through a permitted animal as well ("Zeh v'Zeh Gorem").
(See also CHAZON ISH (14:2) for a similar approach. He adds that although the Isur of Tereifah should not apply to the egg that came into existence after the act occurred to the hen that made it a Tereifah, it still will be prohibited while it is attached to the hen, because, aside from the Isur of Tereifah, the Torah also considers it abhorrent to eat from an animal that is ill due to a mortal wound. Therefore, while the egg is in the hen, it is considered part of an ill animal and is Asur. This is another aspect of the Isur of Tereifah.)
(b) It is true that the egg is considered part of the hen as long as it is in the hen (and if the hen develops another type of Tereifah, the egg would be considered a Tereifah; see Tiferes Yakov for a discussion of this point). Nevertheless, since the egg is not actually an inherent part of the hen, but it is a separate entity inside the hen, it retains its independent status such that it becomes permissible the moment it leaves the hen.
A similar Halachah is found in the Mishnah in Kelim (19:5-6). The Mishnah says that when a sash was tied around a bed at the time that the bed touched a Mes, the sash becomes Tamei Mes (and requires a Taharah process of seven days) and remains Tamei Mes even after it is removed from the bed. In contrast, when the sash was wrapped around the bed after the bed had touched the Mes, the sash is Tamei Mes (and requires a Taharah process of seven days) only as long as it remains wrapped around the bed. Once it is removed, it no longer requires the Taharah process (of seven days) that applies to an object that touched a Mes. Rather, it can become Tahor after one day, like an object that touched another object that touched a Mes. (M. KORNFELD)

58b----------------------------------------58b

3) THE POWER OF THE MOSQUITO
QUESTION: The Gemara relates that people say that a mosquito can carry iron that is equal to the weight of sixty Maneh (one Maneh is equal to a hundred silver coins) on its stinger. RASHI explains that this means that its bite is very effective.
Why does the Gemara emphasize the painfulness of the bite of a mosquito in this way?
ANSWER: The MAHARSHA explains that the mosquito, which damages with its mouth, symbolizes a person who slanders others with his mouth by speaking Lashon ha'Ra. Such a person should not think that his words can do no harm, but rather he should know that his words can be extremely harmful.
We may apply this approach to explain the other incident involving mosquitoes recorded in the Gemara. The Gemara relates that a mosquito's wife quarrels with her husband for seven years when she discovers that he found a fat person and sucked the person's blood without telling her. This symbolizes that Lashon ha'Ra harms even the one who speaks it. One who speaks Lashon ha'Ra believes that he suffers nothing, and that it is only the subject of his Lashon ha'Ra who suffers. The truth is that Lashon ha'Ra harms even the person who speaks it (see Erchin 16b). In the case of the mosquito, when the other mosquito hears that this mosquito bit (i.e. spoke Lashon ha'Ra) without informing her, she no longer wants to be his friend. (M. KORNFELD)
4) WORMS BORN IN FRUIT
QUESTION: Shmuel states that harvested dates are permitted after twelve months have passed, and we are not concerned that there are worms inside of them. We assume that any worms inside were born there (and thus never attained the status of "Shoretz Al ha'Aretz"), and they dried up and died after twelve months.
The RA'AVAD (cited by the ROSH) asks an obvious question. The Torah prohibits eating not only live insects, but also dead insects. How can Shmuel permit the dates if there are dead worms in them?
ANSWER: The RA'AVAD and RAN answer that after twelve months, the worms in fruit not only die, but they also disintegrate (this is the meaning of the words, "Eino Miskayem"). Unlike whole insects, an insect which disintegrates becomes Batel b'Shishim in the permitted fruit.
5) HALACHAH: INSECTS IN FRUITS
QUESTION: Shmuel states that harvested dates are permitted after twelve months have passed, and we are not concerned that there are worms inside of them. We assume that any worms inside were born there (and thus never attained the status of "Sheretz ha'Shoretz Al ha'Aretz"), and they dried up and died after twelve months.
Why does Shmuel mention specifically "dates" and not fruit in general?
ANSWER: The RAN writes that one may infer from the fact that Shmuel specifically mentions "dates" that dates are more problematic than other fruit and are suspected of being infested even when no signs of infestation are visible. This teaches that a food that is often infested must be examined before consumption. (This also seems to be the intent of RABEINU TAM in TOSFOS DH Hani.)
As the ROSH and Ran point out, even insects born inside of fruit become prohibited the moment they exit to the surface of the fruit (as "Sheretz ha'Shoretz Al ha'Aretz"; see 67b). Consequently, any remnants of insects found on the fruit's surface even after twelve months must be removed. They add that it is also probable that insects born inside of the fruit might surface when the fruit is placed in water prior to cooking. Therefore, it is necessary to soak twelve-month-old fruit in water to remove any insects that float to the surface before cooking the fruit.
The Ran cites the RA'AVAD who says that if a commonly infested fruit was cooked without being checked for insects, then b'Di'eved it may be eaten, because of the logic of Sfek Sfeika: perhaps there were no insects in the fruit, and even if there were insects in the fruit, perhaps they disintegrated in the cooking process. This applies even if one or two whole bugs were later found in the fruit. However, if three such bugs were found, the fruit must be discarded, because the fruit becomes "Muchzak" to contain bugs, and it may no longer be suggested that no other bugs were present in the fruit.
6) "YESER K'NATUL DAMI"
OPINIONS: Rav Huna teaches that an animal that has an extra hind leg is a Tereifah, because "Yeser k'Natul Dami" -- "an extra limb is like having a limb removed." What exactly does "Yeser k'Natul Dami" mean, and why does it cause an animal with an extra limb to become a Tereifah?
(a) RASHI explains that "Yeser k'Natul Dami" means that an animal with an extra limb (or organ) is equated to one that is missing that particular limb (that is, it is considered to be missing the natural, normal limb). He equates an animal with an extra limb to one born without that limb ("Chaser").
The TORAS CHAIM explains the logic behind this Halachah. Every limb receives nourishment through its connection to the rest of the body. When another limb shares that connection, it robs the nourishment of the normal limb. Since the limb lacks nourishment, that limb is considered as though it is disconnected from the body.
The RASHASH gives a similar explanation. He writes that the scientists have determined that a person who is blind in one eye is able to see with his other eye much better than a normal person sees with one eye. This is because the brain's total power of vision no longer leads to two eyes, but to one eye, effectively doubling that eye's ability. Conversely, when an animal has an extra limb, the neurological connection now must be distributed to an extra limb, thus weakening the connection to the normal limbs.
(b) The RAMBAN explains that an extra limb does not automatically cause another limb to be considered to be missing. The normal limb is viewed as removed only from the point at which the extra limb is connected to the animal and onwards. For example, an extra leg that grows out of the lower leg of an animal "cuts off" the rest of the natural leg, but not the top of the leg above where the extra leg connects. In such a case, the animal is viewed as though it is missing only the bottom of its leg and it would not be a Tereifah.
The Ramban adds that "k'Natul Dami" does not mean that we view the animal as though it was born without the limb. Rather, we view the animal as though the limb was removed after birth. (Some Tereifos, such as the lack of a spleen, apply only when the organ was once in the body and was removed.)

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