Question: But that creates a contradiction between R. Meir's position regarding the animal (suspecting that it will die) and his position regarding the barrel (where he does not suspect that it may break)!?

Answer: Death is more likely (and out of one's control) than breakage.

Question: But we have created a contradiction in the positions of R. Yehudah who permits using the animal but forbids relying on the barrel!?

Answer: R. Yehudah forbids the case of the barrel because he does not hold of Bereirah, not because of concern for the barrel's breaking.

Question: But we have an indication from the Seifa of the barrel Beraisa that R. Yehudah is concerned about the breaking of the barrel!?

They (including R. Yehudah) challenged R. Meir by asking if he is not concerned about the barrel breaking (leaving the person having drunk Tevel)!

R. Meir responded with lack of concern.

Clearly, then, R. Yehudah is concerned about its breakage!

Answer: R. Yehudah was asking R. Meir only according to R. Meir's position, holding of Bereirah (R. Yehudah himself would not be bothered by the question since the option of designating future barrels does not exist).

Question: But we find R. Yehudah concerned about death (as R. Yehudah teaches that we designate a replacement for the wife of the Kohen Gadol, lest his wife die)!?

Answer: We were already taught regarding that Mishnah that extra measures were taken to insure the Kaparah of Yom Kipur.

Regardless of which concern we adopt, it is clear that the prohibition of using an animal is mid'Rabanan, and that, mid'Oraisa, an animal could be a Mechitzah.

Question: If so, then is there a Machlokes whether an animal receives Tum'ah when it serves as a grave cover?

Answer: We reject the explanations given by Abaye and R. Zeira (see 23a Para. 3.c and d.) and provide new explanations (by R. Acha b. Yakov) for the position of R. Meir forbidding he use of an animal as a Mechitzah.

R. Meir holds that any Mechitzah which depends on air is not a Mechitzah.

Alternately, R. Meir holds that anything which is not man-made cannot serve as a Mechitzah.

Question: When will these explanations differ?

Answer: In the case of a wall supported by a balloon.

The first explanation would invalidate such a Mechitzah since it is supported with air.

It is, however, man-made.

Question: What is the rationale for R. Yosi ha'Gelili who taught (above 23a para. 3.a.2.) that Gitin may not be written on an animal?

Answer: The Beraisa derives it from the requirement of Sefer, which is inanimate.

Question: What is the rationale of the Rabanan who argue with R. Yosi ha'Gelili on this matter?

Answer: Sefer refers to the nature of the thing written, not to the material written upon (which would have been implied by BaSefer).

Question: Then how do the Rabanan, who do not need VeChasav to teach that other things (wood, leaves, etc) may be used (since Sefer does not limit the materials used), interpret VeChasav!?

Answer: They learn from it that a woman may only be divorced with the writ, not with money (we might have derived this from Kidushin).

Question: Whence will R. Yosi ha'Gelili learn this restriction?

Answer: From the words Sefer Kerisus, teaching that only a Sefer, and not anything else (including money) may effect a divorce.

Question: Why didn't the Rabanan learn this from Sefer Kerisus, as opposed to learning it from VeChasav?

Answer: Sefer Kerisus is needed to proscribe the use of conditions in a Get which would permanently bind the wife in the future (as taught in the Beraisa that a permanent [as opposed to a temporary] condition would invalidate the Get).

Question: Whence will R. Yosi ha'Gelili derive this Din?

Answer: From the expansion of the sufficient word Kares to the word Kerisus.

Question: What will the Rabanan do with this expansion?

Answer: They do not use the difference between Kares and Kerisus for this Derashah.

It is permitted to use trees as the Mechitzos of a Sukah (where the Sechach does not rest on them).

(R. Acha b. Yakov): A Mechitzah must be able to withstand a normal wind.

Question: But what of the swaying of the trees in our Mishnah?

Answer: Our Mishnah speaks of firm trees.

Question: But the branches and leaves (which fill in the spaces of the walls) are subject to the wind?

Answer: The branches must be secured.

Question: If so, what is the news of our Mishnah which permits the use of trees as Mechitzos?

Answer: We might have prohibited such a Sukah lest the person come to make use of the trees during Sukos.

Question: But we find that a tree may serve as a Mechitzah when we are looking for a corner Deyumad around a public well!?

Answer: There, too, its branches are secured.

Question: If a tree is a secured Mechitzah, then why, regarding the Halachos of Eiruvin, does it only permit the area of a Beis Sasayim (the underside of the tree should constitute an area which has been intentionally closed off for residence, which can be up to any size)?

Answer: It is not designed to be a Mechitzah for the purpose of the area underneath it, rather it is a Mechitzah for the field which lies beyond it (which makes it an area closed off for non-residence which only permits a Beis Sasayim).