WHAT HILLEL AND SHAMAI ARGUED ABOUT
(Rav Yehudah): There was an argument about all 18 things decreed.
Question (Beraisa): They agreed about everything.
Answer: On that day (of the vote) they argued, on the morrow [Beis Hillel retracted and] they agreed.
(Rav Huna): Hillel and Shamai argued about three things:
(Argument #1) (Mishnah - Shamai): One must separate Chalah from a dough of at least a Kav of flour;
Hillel says, [a dough of at least] two Kavim is liable;
Chachamim say, one and a half Kavim are liable.
After measures were increased, one and a quarter [of the new] Kavim are liable.
R. Yosi says, one and a quarter Kavim are exempt, more than this is liable.
(Argument #2) (Mishnah - Hillel): A Hin (12 Lugim) of Mayim She'uvim is Posel a Mikvah;
[Normally, Chachamim discuss Lugim] - Hillel said 'Hin', for one must repeat exactly what he heard from his Rebbi;
Shamai says, nine Kavim (#2) is Posel;
Chachamim say, neither of these is correct, but they did not know the Shi'ur until two weavers from Sha'ar ha'Ashpah testified in the in the name of Shemayah and Avtalyon that the Shi'ur is three Lugim - the testimony was accepted. (Their profession and residence were recorded to teach that no one should shy away from the Beis Medrash - people of a lowly profession from a lowly place established the Halachah!)
(Argument #3) (Mishnah - Shamai): If any woman sees that she became Nidah, Dayah Sha'atah (she is Teme'ah from now and onwards, not retroactively);
Hillel says, she is retroactively Teme'ah from her last Bedikah (when she checked herself and found herself to be Tehorah).
Chachamim say, she is never retroactively Teme'ah for more than 24 hours; if her last Bedikah was in the last 24 hours, she is retroactively Teme'ah from then.
Questions: They argued about other things!
Question #1 (Mishnah - Hillel): We do Semichah on Nedarim and Nedavos on Yom Tov;
Shamai says, we do not Somech on Yom Tov.
Answer: Rav Huna only lists arguments that started with Hillel and Shamai (the previous Nesi'im and Avos Beis Din argued about Semichah).
Question #2 (Beraisa -Shamai): If one harvests grapes in order to make wine, the juice that drips from them is Machshir them (for he wants the juice to exude);
Hillel says, it is not Machshir.
Answer: That is not counted, for Hillel later agreed to Shamai.
THE DECREES OF TUM'AS CHUTZ LA'ARETZ
(Beraisa): Yosi ben Yo'ezer and Yosi ben Yochanan decreed Tum'ah on Chutz la'Aretz and on glass vessels;
Question: This was decreed by Chachamim 80 years before the Churban (long after Yosi and Yosi)!
(R. Yishmael b'Rebbi Yosi): The evil kingdom (Romi) started to conquer Eretz Yisrael 180 years before the Churban;
They decreed Tum'ah on Chutz la'Aretz and on glass vessels 80 years before the Churban;
Forty years before the Churban, the Great Sanhedrin exiled itself to Chanuyos (a place in Har ha'Bayis).
Question: What do we learn from this?
Answer: (Rav Yitzchak bar Avdimi): After they exiled themselves, fines were not enforced.
Objection: That cannot be! (Fines do not depend on the Sanhedrin sitting in its place; also, Rav Yehudah taught that [after the Churban] R. Yehudah ben Bava gave Semichah to five Chachamim, enabling the continuation of collection of fines!)
Correction (Rav Nachman bar Yitzchak): Rather, after they exiled themselves, capital punishment was not enforced.
Suggestion: Perhaps Yosi ben Yo'ezer and Yosi ben Yochanan lived [and made their decrees] 80 years before the Churban!
Rejection (Beraisa): The Nesi'im during the last 100 years before the Churban were Hillel, Shimon, Gamliel [ha'Zaken], and Shimon (the father of R. Gamliel who was Nasi in Yavneh);
Yosi and Yosi were long before Hillel!
Answer #1: Rather, Yosi and Yosi decreed Tum'ah on dirt of Chutz la'Aretz and to burn Terumah that become Tamei on account of it - they did not decree about the airspace of Chutz la'Aretz;
Chachamim 80 years before the Churban decreed Tum'ah on the airspace of Chutz la'Aretz, and to Toleh Terumah that become Tamei on account of it.
Inference: The first decree [about Tum'as Chutz la'Aretz for which we burn Terumah] was to burn.
Objection: But Ilfa taught that the initial decree regarding [Terumah that touched Stam] hands was to burn it;
Inference: The first decree of other things was not to burn!
Answer #2: Rather, Yosi and Yosi decreed to Toleh on account of dirt of Chutz la'Aretz, they did not decree on the airspace;
Chachamim 80 years before the Churban decreed to burn on account of the dirt, and to Toleh on account of the airspace.
Objection: The decree was made [later,] in Usha!
(Mishnah): There are six cases in which we burn Terumah on account of a doubt - if it became Tamei through a Beis ha'Peras (a field in which a grave was plowed or lost), through dirt from Chutz la'Aretz, through clothes of an ignoramus (someone not careful about Tum'ah), through Kelim that are found, through spit (perhaps it is from a Zav), and through urine, even if it could be of an animal (and even if it is a person's, perhaps the person was Tahor).
For Vadai Maga (something definitely touched one of these), even though the Tum'ah is Safek, we burn Terumah;
R. Yosi says, in Reshus ha'Yachid, we burn even for Safek Maga;
Chachamim say, in Reshus ha'Yachid we Toleh for Safek Maga; in Reshus ha'Rabim, it is Tahor.
(Ula): These six Sefekos were enacted in Usha.
Answer #3: Rather, Yosi and Yosi decreed to Toleh on account of dirt of Chutz la'Aretz, they did not decree on the airspace;
Chachamim 80 years before the Churban decreed to Toleh also on account of the airspace;
In Usha they decreed to burn on account of the dirt, they left the decree to Toleh on account of airspace as it was.
TUM'AH OF GLASS VESSELS
Question: Why did they decree Tum'ah on glass vessels?
Answer (Reish Lakish): Because they are made from sand, Chachamim made them like Klei Cheres (earthenware vessels).
Question: But immersion in a Mikvah is Metaher them [unlike Klei Cheres]!
(Mishnah): The following are a Chatzizah (blockage) that invalidate immersion - pitch and Mor (myrrh (a spice) or sap) on glass vessels...
Answer: Immersion does not Metaher vessels or pure glass - the Mishnah discusses vessels that were punctured and sealed with a drop of molten lead;
It is like R. Meir, who says a vessel gets the law of its Ma'amid (what makes it usable) - immersion is Metaher metal vessels.
(Beraisa - R. Shimon ben Gamliel): If a glass vessel was punctured and sealed with a drop of molten lead, R. Meir is Metamei, Chachamim Metaher.