Question (R. Bun bar Chiyah, to R. Ze'irah): Does a widow to a Kohen Gadol need Chalitzah? (MEICHAL HA'MAYIM - a Mishnah teaches that she does! He asks whether this is mid'Oraisa or mid'Rabanan.)

Answer (R. Ze'irah): [His] Kidushin takes effect on her - can you say that she does not need Chalitzah?!

Question (R. Bun bar Chiyah, to R. Ze'irah): Kidushin takes effect on an Ailonis (one who does not develop like a normal female), and you say that she does not need Chalitzah?!

Answer (R. Ze'irah): There is a different reason to exclude an Ailonis [from Yibum or Chalitzah] - "Asher Teled" excludes this (an Ailonis), who cannot give birth.

Question: Why do you learn all Arayos from Achos Ishto to forbid [R. Yosi bar Bun]? Learn from Eshes Achiv to permit!

Answer #1 (R. Mana): We learn two Isurim (Eshes Achiv and another Ervah) from two Isurim (Eshes Achiv and Achos Ishto). We do not learn two Isurim (Eshes Achiv and another Ervah) from one Isur (Eshes Achiv alone).

Answer #2 (R. Lazar citing R. Avun): Any [Isur] that comes due to a cause, when the cause is Batel, the Isur is Batel. Any [Isur] that does not come due to a cause, even if the cause is Batel, the Isur is in its place;

Question: What does this refer to?

Answer (R. Yosi bei R. Bun): It is the 15 women (Arayos of our Mishnah. If one of them married his brother, it is another reason to be forbidden, but it is not the cause, for she was forbidden even without marrying his brother);

Do not say that his daughter, before she married his brother, she was forbidden to him, and after she married his brother, she is permitted to him (i.e. when she falls to Yibum to him).