The text: This is Rashi's text. The text in Seforim was "Shi'urim are written!" I.e. R. Chanan expounds them from "Eretz Chitah u'Se'orah..." We say in Sukah (5b) that the entire verse teaches about Shi'urim;

We answer [the question that they are written] that the Shi'urim of punishments [are a tradition].

Support #1 (for Rashi): The text should not say this. [According to this text,] what was the answer "Shi'urim of punishments"? We can still ask that they are written!

Support #2: Wherever the Gemara asks this (Shi'urim are written!), in Sukah (5b) and Eruvin (4a), we bring R. Chanan's entire teaching, and here we do not bring it.

Support #3: Also, why don't we answer here like the Gemara answered there, that the verse is a mere Asmachta?

Support #4: Also, why don't we ask that also punishments are written? (This is a stronger question than in the first support. The only way to answer this question is to say that he meant Shi'urim of punishments!)

Conclusion: Rather, the Gemara here asked that punishments are written. It did not ask about Shi'urim, for it relied on the answer given there [in Sukah, that the verse is a mere Asmachta].

R. Tam's opinion: In Eruvin (79b), we say that one who is Mekadesh is Yotzei only if he drinks Malei Lugmav (which connotes filling both cheeks). R. Tam explains that there also, it is k'Malei Lugmav (to fill one cheek). The reason is that we require an amount that settles the mind.

Suggestion: Perhaps it (the Shi'ur to be Yotzei Kidush) is literally Malei Lugmav.

Rejection #1: If so, it is more than a Revi'is, like it is clear from our Gemara;

When we establish our Mishnah to mean k'Malei Lugmav, then we ask that this is a leniency of Beis Shamai. Initially, when we thought that it is Malei Lugmav proper, this was not difficult.

Summation of Rejection #1: How could we require so much? We say in Pesachim (108b) that the Shi'ur for the four cups is a Revi'is, and one of them is the cup of Kidush. How can one be Yotzei Kidush, if he must taste Malei Lugmav?!

Rejection #2: If Malei Lugmav is required, this is more than is needed to settle the mind, which is only k'Malei Lugmav. Why does the Shi'ur depend on each person?

This is not difficult if the Shi'ur is k'Malei Lugmav, like we answer below. Rabanan knew that a person's own k'Malei Lugmav settles his mind, but k'Malei Lugmav of another [smaller] person does not settle his mind. (Maharsha and Tosefes Yom ha'Kipurim suggest other ways to fix the text of Tosfos.)

Question (R. Tam): In Eruvin (80b), we say that (the Shi'ur of bread in) two meals for an Eruv is 18 Gerogeros. In Eruvin 82b, R. Shimon says that it is two thirds of a loaf that is a third of a Kav. This is two meals, and it is five and a third Beitzim, for the entire loaf is eight Beitzim.

The Halachah follows R. Shimon, for we always say that a Beitzah is the Shi'ur of Tum'as Ochlim, and according to R. Shimon the calculation works, but not according to the other Tana'im.

All Tana'im agree that half of half of half of the loaf is the Shi'ur of Tum'as Ochlim. This is clear from the Sugya there.

When you divide 18 Gerogeros into five and a third Beitzim, for each of these is two meals, we find that each Beitzah is three Gerogeros and three eighth's of a Gerogeres. This is because five and a third Beitzim is 16 thirds of an egg, so for each third of an egg there is one and an eighth Gerogeros.

A Gerogeres is bigger than a k'Zayis. This is clear from Shabbos 91a, like I explained above.

Summation of question: If so, how do we say in Kerisus (14a), regarding [being liable four Chatas and an Asham for] one eating, that one cannot swallow more than two k'Zeisim at once? (One can swallow k'Beitzah at once, which is more than three Gerogeros, and a Gerogeres is more than a k'Zayis!)

Answer #1 (Ri): Even though we hold like R. Shimon that k'Beitzah is the Shi'ur of Tum'as Ochlim, we do not hold like him regarding two meals for an Eruv. Rather, it is clear there that we hold like R. Meir or R. Yehudah;

Rav Yosef and Rava hold like R. Meir, and they agree that k'Beitzah is the Shi'ur of Tum'as Ochlim, like R. Shimon.

Half [a loaf of eight eggs] is the Shi'ur for a house with Tzara'as (if one delays there long enough to eat a half-loaf, the clothes he is wearing become Tamei), half of half [a loaf] is the Shi'ur to be Metamei a person (mid'Rabanan, for eating this much Tamei food), and half of half of half [a loaf] is the Shi'ur for Tum'as Ochlim.

This does not refer to R. Meir and R. Yehudah, rather, to R. Shimon and R. Yochanan, who mentioned the Shi'ur of a loaf.

Support: There, in a Beraisa, R. Yehudah teaches that the Shi'ur of half a Pras (half-loaf) is slightly less than two eggs.

Inference: He holds like R. Shimon, who says that half of half [a loaf] is the Shi'ur to be Metamei a person, i.e. two eggs.

Answer #2 (R. Tam): Here we discuss Gerogeros without pits. They can be pressed and mashed more. It is easier to put them in Beis ha'Bli'ah (where one swallows);

Olives have pits. They are hard and round. They do not stick in Beis ha'Bli'ah.

Therefore, the Shi'ur of two hard olives is like the Shi'ur of more than three Gerogeros, which are soft and easy to eat;

Koseves ha'Gasah is more than a k'Zayis and Gerogeres, and less than k'Beitzah.

Rejection (Ri): Gerogeros do not have a pit. They are pressed figs! Kerisus 14a, which says that the Beis ha'Bli'ah does not hold more than [the volume of] two olives, discusses meat! It is not relevant to discuss pits, or being hard and round.

Question (Riva): In Shabbos (14a), we say that one [who eats Tamei food] becomes Tamei, because sometimes one eats Tamei food and puts Terumah liquids in his mouth, and he is Metamei the Terumah.

If so, one should become Tamei for [eating] a Beitzah of Tamei food, since it has a Shi'ur of Tum'as Ochlim!

Answer (Riva): The decree was lest one put Terumah liquids in his mouth. Chachamim know that eating less than two Beitzim does not make one thirsty to drink.

Question (Riva): Why does one become Tamei for drinking Tamei liquids only if he drank a Revi'is, like it says in Me'ilah (17b)?

Any amount of a liquid is Metamei other [food and drink] (Pesachim 14a, Berachos 52a)!

Answer #1: R. Tam explained that mid'Oraisa, only a Revi'is of liquid is Metamei others. Chachamim decreed that any amount is Metamei others;

He can say that Chachamim wanted to decree [to be Metamei] only one who drinks enough liquid to be Metamei mid'Oraisa.

Answer #2 (R. Tam): There were two decrees. Initially, they decreed that eating two Beitzim [of Tamei food] disqualifies from eating Terumah, but he may touch Terumah. The words "to disqualify the body" connote like this;

This was not due to the reason given in Shabbos (14a), rather, for another reason.

Just like people say that one who eats Tamei food may eat Terumah, even though they touch each other in his body, people will equate touching inside the body and outside, and come to permit touching Terumah to Tamei food.

Question: If so, they should have decreed about k'Beitzah!

Answer: When one eats k'Beitzah, less than k'Beitzah enters his stomach, for some must remain between his teeth and gums;

Once there is reason to make the Shi'ur more than k'Beitzah, they established it to be two eggs;

Regarding liquids, a Revi'is suffices, for they do not remain in the teeth and gums.

Explanation (of R. Tam - Ri): We made the Shi'ur two eggs. Since there is reason to make the Shi'ur more than k'Beitzah, they established it to be half the Shi'ur of a half-loaf for a house with Tzara'as, everyone according to his opinion.

Eruvin 83a connotes like this;

The decree of two eggs was an early decree, much before the 18 decrees [on the day that Beis Shamai outnumbered Beis Hillel - Shabbos 13b].

Support #1: Our Gemara thought that it is mid'Oraisa. It asked from "v'Nitmesam Bam", to disqualify the body mid'Oraisa;

If it was decreed only amidst the 18 decrees, how could the Gemara err about this? Everyone knew them, and they spread (Avodah Zarah 36a)!

Support #2: If this was one of the 18 decrees, the one who asked that it is mid'Oraisa would be missing one of the 18!

Note: He could hold that the decree of Tum'as Nochriyos was among the 18, like we answer for others (Shabbos 16b, 17a)! Perhaps Tosfos learns from the fact that the Gemara did not even ask that he is missing a decree.

Ri's explanation (cont.): Later, amidst the 18 decrees they decreed that one who eats a Rishon [l'Tum'ah becomes a Sheni l'Tum'ah] even for eating just k'Beitzah;

According to the reason there (lest he put Terumah liquids in his mouth together with Tamei food), his body is disqualified even from touching Terumah.