Question (to Rav Yehudah Gaon): What is the source mid'Oraisa that a Nidah must immerse?

Answer #1 (Rav Yehudah Gaon): This is a Kal va'Chomer from what she touches. (It must be immersed to become Tahor.)

Answer #2 (R. Tam): We expound (Avodah Zarah 75b) "Mei Nidah" to mean water in which a Nidah immerses (a Mikveh).

Answer #3 (Ri): We expound (Shabbos 64b) "veha'Davah b'Nidasah" that she is Nidah until she enters water.

Rashi's opinion: In Shabbos (66a), Rashi explains that [the wooden leg] is not a Tachshit (ornament).

Inference: He forbids because it is considered a load. It is not a shoe, for a shoe is only of leather, but not of wood.

Support - Citation (66a): According to R. Meir, Chalitzah (removal) of the wooden leg of an amputee is Kosher, for it is considered a shoe. According to R. Yosi it is Pasul, for it is not considered a shoe.

Question (R. Tam): Here we conclude that they argue about whether or not we are concerned lest it fall off and he will come to carry it four Amos, but all agree that it is a shoe;

There we say there that R. Meir permits using it for Chalitzah, but R. Yosi does not!

Answer (Ri): R. Yosi holds that just like we are concerned lest it fall, since it is wide, one may not use it for Chalitzah, for the same reason;

Citation (Yevamos 103b): "Na'alo" (his shoe) - it must be proper for him. This excludes a big shoe that he cannot walk in.

Question (R. Shimshon): A Beraisa (Yevamos 103a) says that Chalitzah of the wooden leg of an amputee is Kosher. Chalitzah of a cloth sock is Pasul;

Citation (103a): Which Tana is Machshir the wooden leg of an amputee? It is R. Meir. A Mishnah says that R. Meir permits an amputee to go out [on Shabbos] with a wooden leg, and R. Yosi forbids;

Citation (cont.): [The Seifa of the Beraisa teaches that] Chalitzah of a cloth sock is Pasul. This is like Rabanan!

Summation of R. Shimshon's question: The Gemara's question there connotes that 'Rabanan' are R. Yosi, who argues with R. Meir. What connotes that the Seifa is like R. Yosi more than R. Meir?

R. Yosi does not consider an amputee's wooden leg to be a shoe, for it often falls off. We cannot say so about cloth socks. Perhaps R. Yosi agrees [that it is a Kosher Chalitzah]!

Answer (Ri): Surely, the questioner thought that R. Yosi's reason [to disqualify an amputee's wooden leg] is that he holds that only a leather shoe is considered a shoe;

There is no other way to establish [the Seifa, which says that] Chalitzah with a cloth sock is Pasul;

If also R. Yosi considers it a shoe, [the Seifa] is not R. Meir, and not R. Yosi!

In the conclusion, the entire Beraisa is R. Meir. He disqualifies a cloth sock because it does not protect. If so, we can say that R. Yosi's reason is lest it fall.

Question: Since initially, we thought that R. Yosi's reason is lest it fall, what was the answer, that since the Seifa is Rabanan, also the Reisha is Rabanan, and in the Reisha it is covered with leather?

Why is it permitted? Even if it is covered with leather, we should be concerned lest it fall!

Answer #1: The Gemara means that it is covered with leather from the inside. It narrows and conforms to the size of his foot [so it is not prone to fall].

Answer #2: Alternatively, since it is covered, he can bend it so it will stay firmly around his leg.

Rashi's opinion: In Shabbos, Rashi explained that one whose leg was cut off makes a form of a leg and carves a bit into it, to put the end of his thigh into it.

Question #1 (R. Pores): If so, why does R. Yosi forbid? He cannot walk any other way!

Even though we conclude here that R. Yosi decrees lest it fall, and he will come to carry it, [according to Rashi there is no reason to decree;] if it falls, he cannot move until he resumes wearing it!

Question #2 (R. Pores): Abaye (Shabbos 66a) says that it is not Tamei Medras because he does not lean on it. According to Rashi, this is the ultimate support!

Answer (to Question #1 - Ri): He does not need the wooden leg so much. He supports himself with sticks in his hands, like lame people. He does not lean on the wooden leg at all;

These [sticks in his hands] are his Semuchos (supports). The Mishnah says that all permit him to go out with them on Shabbos.

This is unlike Rashi said, that Semuchos are pieces of hide for the ends of his thighs, and he drags himself on the ground when both of his legs are cut off.

Answer (to Question #2): This answers also the question from Abaye. It is not considered Medras, because he does not support himself on it, only sometimes he leans on it a little, and sometimes it does not touch the ground at all!

R. Pores' opinion: One whose foot was cut off makes a stick like a shoe, and puts it in place of a foot, and it looks like he has a foot.

He may go out with it on Shabbos, like with his shoes. He bends his thigh back, and ties wooden Semuchos called stilts from the hip socket. He supports his thigh with it, and walks with it;

These are his Semuchos. We say that they are Tamei Medras, and he may go out with them on Shabbos, and he may enter the Azarah with them. (They are not considered shoes.)

The stick that he puts in place of his foot is only so people who see him will think that he has a complete foot, but due to illness he cannot step on it.

If the stick has a receptacle for Kesisin, it is Tamei. Kesisin are rubber, tufts, or anything soft that he puts in the stick for comfort, so it will not hurt when his leg touches the Kav.

[The Mishnah says that if it has a receptacle, it is] Tamei. One opinion in the Gemara says that it [receives] Tum'as Mes. Another opinion in the Gemara says that it [receives] Tum'as Medras, for he leans on it.