1)

(a)Rebbi Eliezer and Rebbi Yehoshua agree that if someone eats a food which is a Sheini, he becomes a Sheini. They argue however, by someone who eats a Rishon - Rebbi Yehoshua holds that he becomes a Sheini, whereas according to Rebbi Eliezer, he becomes a Rishon.

(b)Someone who is a Rishon is Tamei, to make Terumah that he touches a Sheini (which can still make other food that is Terumah a Shelishi). Whereas someone who is a Sheini (by Chulin) is Pasul, but cannot transmit Tum'ah any further.

(c)In the opinion of Rebbi Eliezer, someone who eats a Shelishi becomes a Shelishi. According to Rebbi Yehoshua, he becomes a Sheini (to make Kodesh a Shelishi).

(d)The Mishnah in Taharos (which talks of someone eating Chulin that is a Shelishi) must be speaking about 'Chulin she'Na'asu Al Taharas Terumah' - because as far as ordinary Chulin is concerned, the lowest level of Tum'ah is a Sheini.

2)

(a)According to Rebbi Yehoshua, someone who eats a Shelishi becomes a Sheini for Kodesh - because, guarding Chulin 'Al Taharas Terumah' from Tum'ah, is not considered guarding for Kodesh. We suspect that the Shelishi is really a Rishon as far as Kodesh is concerned, and the person who ate it therefore becomes a Sheini.

(b)Chazal decreed Tum'ah on someone ...

1. ... who eats food which is a Rishon or a Sheini - because it can happen that a Kohen who is eating Tamei food, puts Terumah drink in his mouth, thereby rendering it Pasul.

2. ... who drinks Tamei beverages - because whilst he is drinking a Tamei beverage, he may put Terumah food in his mouth and render it Pasul.

(c)Although the two decrees appear to be one and the same, Chazal nevertheless saw fit to issue the second decree independently, since, although it is common to drink whilst eating, it is not common to eat whilst drinking.

(d)Chazal's decrees on Tum'ah, safeguarding Terumah - are based the Pasuk in Korach "es Mishmeres Terumosai"), a warning to the Kohanim to safeguard their Terumah against Tum'ah (and the word "Mishmeres" implies Rabbinical decrees).

3)

(a)Initially, they used to Tovel in Mikva'os in caves, where the water was repugnant. After the Tevilah therefore, it became cstomary to pour over themselves three Lugin of drawn water, in order to rinse off the smelly water of the Mikveh. Eventually, it reached the stage when people were saying that it is not the Mikveh water which purifies, but the drawn water - so they decreed that someone who follows his immersion in the Mikveh with bathing in drawn water, becomes Tamei.

(b)We learn from "Ach Ma'ayan u'Bor Mikveh Mayim" - that only a natural collection of water is Kasher for Tevilah, but not drawn water.

(c)The decree that three Lugin of water that fell on a person renders him Tamei - is merely a necessary extension of the previous decree. Because if one remained Tahor in the latter case, people would not understand why he should be Tamei in the former.

4)

(a)They decreed ...

1. ... that Sifrei Kodesh should render Terumah, Tamei - because of the custom of the Kohanim to put their Terumah away next to Sefarim. The former, they claimed, was holy just like the latter. Their reasoning however, backfired, when the mice, which were attracted by the Terumah, also began chewing the Sefarim. This prompted the Chazal to decree Tum'ah on the Sefarim - to encourage the Kohanim to discontinue placing their Terumah next to them.

2. ... Tum'ah on hands - because hands tend to touch everything. Sometimes one touches the dirty parts of the body, and then the Terumah, making the Terumah disgusting to eat.

(b)The reason for the latter cannot be because he may have touched something Tamei, thereby rendering one's hands Tamei, because if it were, then why would he only be a Sheini, and not a Rishon? Why do we not suspect that perhaps he touched an Av ha'Tum'ah? Secondly - why are only the hands Metamei Terumah? If his hands touched Tum'ah, then his whole body should be Tamei, and render Terumah which touched it, Tamei? And thirdly - it would not suffice just to wash one's hands to remove the Tuma'h, but to immerse one's entire body in a Mikveh.

(c)As a result of the decree on hands, we are obligated to wash our hands before eating bread.

5)

(a)When Rebbi Parnach said that someone who holds a Seifer-Torah with bare hands will be buried naked - he meant that someone who holds the parchment of the Sefer-Torah with his bare hands, will lose the reward of whichever Mitzvah he is currently performing (see Tosfos DH 'be'Lo').

(b)It is obvious that the decree that hands become Tamei through touching a Sefer preceded before the decree that S'tam hands are Tamei, because after the latter decree, the former would be superfluous.

6)

(a)A Tevul Yom is indeed Tamei d'Oraysa - and must be erased from the list of the eighteen decrees.

(b)'Food which became Tamei through liquids.' The liquids mentioned here cannot have become Tamei through touching a Sheretz - because liquid that became Tamei through touching a Sheretz is Tamei and Metamei min ha'Torah, and would not require a Rabbinical decree.

(c)We must therefore be speaking about - liquid that became Tamei through contact with S'tam Yadayim (or any of the Tum'os which render Terumah Pasul), which they decreed on account of liquid which became Tamei through a Sheretz.

(d)When Chazal decreed Tum'ah on liquid and not on food - they took their cue from the Torah, which renders liquid fit to receive Tum'ah immediately, whereas food cannot receive Tum'ah , before it has had contact with a liquid.

7)

(a)'Vessels which received Tum'ah through liquids'. Why can the liquids mentioned here not be referring to the liquids of a Zav - because the liquids of a Zav are Tamei d'Oraysa, and do not require a Rabbinical decree.

(b)The liquid that we are talking about (which renders vessels Tamei) must be referring to liquid which received Tum'ah through a Sheretz, which although it is Tamei d'Oraysa, it cannot transmit Tum'ah to vessels - mi'd'Oraysa - since, min ha'Torah, vessels can receive Tum'ah only through an Av ha'Tum'ah.

8)

(a)Yossi ben Yoezer and Yossi ben Yochanan decreed Tum'ah on the lands of the gentiles, and on glass vessels. Shimon ben Shetach decreed on Kesubah, and Tum'ah on metal vessels. Shamai and Hillel decreed Tum'ah on the hands. (All of these preceded the eighteen decrees of Beis Shamai and Beis Hillel). Yossi ben Yoezer and Yossi ben Yochanan decreed Tum'ah on the lands of the gentiles - because of the unmarked graves there, and non-Jewish corpses are Metamei through touching and carrying, according to Rebbi Shimon, and even be'Ohel, according to the Rabbanan.

(b)Shimon ben Shetach decreed - that all a person's property should be considered collateral for his wife's Kesubah (rather than just setting aside money for her). He issued this decree in order to discourage a person from making a hasty divorce, and telling his wife to take her money and go.

(c)Shamai and Hillel themselves argued only three times.

9)

(a)In fact, Hillel and Shamai did attempt to decree Tum'as Yadayim - but the decree was not accepted until their Talmidim issued it, some years later.

(b)We reject the suggestion that when the Beraisa says Shamai and Hillel, it really means Shamai and his group (of disciples) and Hillel and his group (of disciples) - because if we include Hillel and Shamai in the eighteen disputes that took place between their disciples, then Hillel and Shamai will have argued eighteen times, and not just three!

(c)Nor can we say that Shamai and Hillel decreed a Safek Tum'ah on hands (which means that the Terumah is not burnt), and their Talmidim came and decreed a Vaday Tum'ah - because Ilfa said that the initial decree of hands was that of Vaday Tum'ah, in which case, the Terumah had to be burnt, already from the decree's inception.

10)

(a)Shlomoh Hamelech decreed Eiruvei Chatzeiros and Netilas Yadayim.

(b)Nevertheless, Beis Shamai and Beis Hillel needed to decree Tum'ah on the hands again - because Shlomoh's decree was confined to Kodshim, whereas Beis Shamai and Beis Hillel added the decree on Terumah (a general decree on all S'tam Yadayim - even those of non-Kohanim).