1) A SHALI'ACH WHO DERIVES FORBIDDEN PLEASURE
QUESTION: Rava states that even if Shamai maintains that "Shnei Kesuvim ha'Ba'im k'Echad Melamdin," and even if he does not agree with the Derashah of "ha'Hu," nevertheless he agrees in a case in which a person tells a Shali'ach to have relations with an Ervah or to eat Chelev that the Shali'ach is liable and the sender is exempt, because "we do not find anywhere in the entire Torah that one person derives [forbidden] pleasure and another person is punished for it."
TOSFOS (DH she'Lo Matzinu) is in doubt about who is liable in a case of Me'ilah. When the Meshale'ach told the Shali'ach to go warm himself from the wool of an animal which they did not know was Hekdesh, who is liable for Me'ilah? Is the Meshale'ach liable since, in the case of Me'ilah, the rule is "Yesh Shali'ach l'Devar Aveirah," or is the Shali'ach liable since the act of Me'ilah involves pleasure and is thus comparable to a case of Ervah or Chelev, in which the Shali'ach is liable because of the logic that "we do not find anywhere in the entire Torah that one person derives [forbidden] pleasure and another person is punished for it"?
ANSWER: CHIDUSHEI RABEINU CHAIM HA'LEVI (Hilchos Me'ilah 8) deduces from the words of the RAMBAM that in such a case the Meshale'ach is liable since in cases of Me'ilah, "Yesh Shali'ach l'Devar Aveirah." He refers to the question of Tosfos that "we do not find anywhere in the entire Torah that one person derives [forbidden] pleasure and another person is punished for it," and he explains that there is a difference in the essential nature of the prohibition of Me'ilah and the prohibitions of Ervah and Chelev.
The prohibition of Me'ilah is similar to that of Gezel, theft. Since Hekdesh is the "property" of Hash-m, one may not derive personal benefit from it just as one may not steal the property of another person. In contrast, the prohibitions of Ervah and Chelev are not acts of theft, but acts of pleasure in which one is forbidden to indulge (the act of Bi'ah and the act of Achilah). Only when the essential nature of the prohibition is an act of deriving forbidden pleasure does the logic that "we do not find anywhere in the entire Torah that one person derives [forbidden] pleasure and another person is punished for it" apply. When the essential nature of the prohibition is not the deriving of pleasure but the act of stealing (such as Me'ilah), this logic does not apply. Even though one derives some pleasure from his act of Me'ilah, the Aveirah he performs is not one of deriving Hana'ah per se but rather an act of Gezel, theft. Therefore, Me'ilah is an exception to the rule and "Yesh Shali'ach l'Devar Aveirah."
2) HALACHAH: DESIGNATING WITNESSES TO TESTIFY
QUESTION: Rav and Rav Shila disagree about whether a Shali'ach may serve as a witness. The Gemara asks that according to Rav Shila who maintains that a Shali'ach may not serve as a witness, if the reason he may not serve as a witness is that the sender did not explicitly designate him as a witness, when a man instructs two people to be Mekadesh a woman for him and he does not explicitly add, "And you are my witnesses," the Kidushin should not be valid. Rather, Rav Shila's reasoning is "Shali'ach Shel Adam Kemoso"; since the Shali'ach is like the sender, he cannot be a witness because a person cannot serve as a witness for himself.
Although the Gemara concludes that one is generally not required to explicitly designate the witnesses for an act of Kidushin, there are circumstances in which one is required to designate them. The RITVA here writes that when people who are invalid witnesses (such as relatives) are present at the Kidushin, one must designate valid witnesses for the Kidushin so that the testimony of the relatives not invalidate the testimony of the valid witnesses. Since all of the people present at the Kidushin witness the act together, they are considered one group of witnesses, and thus the relatives will invalidate the valid witnesses because of the rule, "If one witness [in a group] is found to be a relative or invalid, then all of the witnesses [in the group] are invalid." One therefore must designate two specific witnesses prior to the Kidushin so that only those two are considered witnesses and no one else present is considered part of the group of witnesses. This ruling of the Ritva is widely accepted (see also KETZOS HA'CHOSHEN CM 36) and is the prevalent practice at most weddings, where the officiating rabbi designates two witnesses before the Chupah.
Why, though, is this practice not performed in all situations that require witnesses? For example, when a monetary transaction (such as a loan or a sale) is performed in the presence of witnesses, specific witnesses should be designated so that any relatives or other invalid witnesses present will not disqualify the valid witnesses.
ANSWER: The RITVA explains that the role of witnesses for Kidushin differs from the role of witnesses in other situations. In the case of Kidushin, the witnesses are "Edei Kiyum" -- their testimony of the event creates the Kidushin. In contrast, in other situations (such as monetary transactions) the role of the witnesses is merely to observe the act so that later they will be able to provide proof if necessary. Indeed, those who witness the transaction are not considered witnesses until later when they come to a Beis Din to testify about what they saw. Hence, as long as the witnesses come to Beis Din without the relative, they remain valid witnesses.

43b----------------------------------------43b

3) A KETANAH'S ABILITY TO ACCEPT A GET
QUESTION: The Gemara quotes the Mishnah in Gitin (64b) in which the Rabanan state that both a Na'arah Me'urasah and her father may accept her Get. Rebbi Yehudah there disagrees and says that only her father may accept her Get.
What is the Halachah in the case of a Ketanah? Does the same dispute apply, or do the Rabanan agree with Rebbi Yehudah that only the father may receive a Get for his daughter who is a Ketanah?
ANSWERS:
(a) RASHI first writes that the same dispute applies to a Ketanah (DH Na'arah). However, Rashi later (DH Hi v'Aviha) writes that everyone agrees in the case of a Ketanah that only the father has the power to receive a Get for the Ketanah.
TOSFOS (DH Tenan) suggests that the two disparate comments of Rashi reflect Rashi's retraction of his original opinion. Rashi originally maintained that only a Na'arah (and not a Ketanah) may accept her own Get according to the Rabanan. Rashi subsequently changed his mind (because of the Gemara on 44b) and wrote that a Na'arah and a Ketanah have the same status, and both may receive their Gitin themselves. (It is interesting to note that according to the explanation of Tosfos, Rashi's final opinion is expressed in his earlier comment, while his earlier opinion is expressed in his later comment. See MAHARSHAL.)
(b) The RIF in Gitin (64b) maintains that the Rabanan agree that in the case of a Ketanah only the father may receive her Get.
The different ways of understanding the opinion of the Rabanan depend on the nature of a Ketanah's right to receive a Get. All opinions agree that if the father has died, even a Ketanah may accept her Get on her own (as is evident from the Sugya on 44b). On the other hand, with regard to all other Halachos (such as Kinyanim and Shelichus) a Katan or Ketanah cannot effect a Kinyan or appoint a Shali'ach (as is evident from the earlier Sugyos). Why is a Get different?
Apparently, the acceptance of a Get is an exception to the rule that a Ketanah cannot effect a Kinyan. Although a Ketanah has no power to effect other Kinyanim, the Torah made an exception to the rule in the case of a Get and empowered a Ketanah to receive a Get.
Alternatively, the Ketanah's ability to receive a Get is not based on her own ability to effect a Kinyan, but it is a right which she inherited from her father. Since -- for matters of Kidushin and Gitin -- she was under the jurisdiction of her father who had full rights to receive her Get, when the father dies his rights are transferred to his daughter. Accordingly, the Ketanah's ability to receive a Get is not essentially different from her ability to effect other Kinyanim. Rather, in the case of a Get the rights of the father are transferred to his daughter, a transfer which does not apply to other Halachos.
The RITVA explains that these two ways of understanding the right of a Ketanah to receive her Get after her father's death are the basis for the dispute between Rashi and the Rif. Rashi maintains that a special Gezeiras ha'Kasuv differentiates between Get and Kinyanim, while the Rif maintains that the right of a Ketanah is due to "Nisroknah Etzlah Yad Avihah" -- she has inherited the rights of her father.