1)

(a)The Mishnah in T'rumos lists three liquids that are forbidden because of Giluy (they were left uncovered) - water, wine and milk.

(b)The Tana gives the time period in which they become forbidden as the time it takes for a poisonous snake to come from close by and drink. Rebbi Yitzchak b'rei de'Rav Yehudah defines from close by as - from the ground directly beneath the handle of the jar containing the liquid.

(c)We amend the Beraisa by adding 'and that it returns to its pit' - because otherwise, he would have seen the snake returning to its pit underneath the jar, and that, if he didn't, it means that there cannot have been one (see also Tosfos DH 'Ve'yishteh').

2)

(a)If, after Shechting and breaking bones all day with the same knife, it is found to be defected, Rav Huna invalidates the Shechitah - because he suspects that it became defected right at the start, on the skin of the animal's neck as he performed the Shechitah.

(b)Rav Chisda - declares the animal to he Kasher, because it is more likely to have become defected when breaking bones than when cutting skin.

(c)When we say that Rav Huna follows his own reasoning, we are referring to - the principle that he cited earlier, that an animal has a Chezkas Isur, until we know that it has been properly Shechted.

(d)Rav Chisda counters this with the argument that - bones will definitely cause the knife to become defected, whilst skin is only a Safek, and we have a principle Ein Safek Motzi mi'Yedei Vaday (which overrides the Chezkas Isur).

3)

(a)Rava cites a Beraisa in support of Rav Huna, which rules that if someone Tovels and, at the end of the day, discovers a Chatzitzah consisting of a species with which he was working all day - his Tevilah is invalid.

(b)We reject out of hand, the counter-argument that the case of ...

1. ... Tevilah is different, because the Tamei person has a Chazakah that he has not Toveled - because, then by the same token, we should place the animal on its Chazakah and say that it has not been Shechted.

2. ... Shechitah is different, because Harei Shechutah Lefanecha (you can see that the animal is lying Shechted before you), because then we should also say - Harei Taval Lefanecha.

3. ... that a Re'usa (a fault) occurred (in connection with the Tevilah) - because then, by the same token, a Re'usa also occurred with the Shechitah.

(c)Rav Chisda nevertheless counters Rav Huna using this last argument - because even if it did, the Re'usa lies in the knife, whereas the Chazakah is in the animal.

4)

(a)The Shechitah of a bird entails - cutting one of the two pipes ...

(b)... the Veshet (the esophagus [the food pipe]) and the Gargeres (the trachea [the wind-pipe]).

(c)The Beraisa rules that after Shechting the Veshet, the Gargeres slips from its place - the Shechitah is Kasher.

(d)The Tana give this example, and not vice-versa (where he Shechted the Gargeres first, before the Veshet slipped from its place), not because there is any difference between the two cases, but - because it is more common for the Veshet to slip.

(e)In a case where the Gargeres slipped ...

1. ... before he Shechted the Veshet - the Tana declares the Shechitah Pasul.

2. ... but they do not know whether it slipped before or after the Shechitah of the Veshet - the Tana rules Kol Safek bi'Shechitah, Pasul.

5)

(a)'Kol Safek bi'Shechitah Pasul however, is a Ribuy - which we initially think comes to include a case of a Safek that occurs in the knife (a Kashya on Rav Chisda).

(b)We refute the Kashya however - by establishing the Ribuy by Safek Shahah, Safek Daras ...

(c)... which the Tana prefers to include rather than a Safek in the knife, according to Rav Chisda - because it constitutes a Re'usa in the animal itself (as we explained earlier).

6)

(a)We rule ...

1. ... like Rav Huna - where the Shochet did not break bones after the Shechitah.

2. ... like Rav Chisda - where he did.

(b)Rav Chisda renders the Shechitah Kasher even if the Shochet did not cut bones after the Shechitah - because he considers the neck-bone (which one cuts after the Shechitah) to be more likely to have caused the defect than the skin (which one cuts before it).

7)

(a)There was a case where, after a Shochet had Shechted thirteen animals, Rav Yosef declared them T'reifah - because after the thirteenth animal, the Shochet discovered that his knife, which he had failed to inspect after each Shechitah, was defected.

(b)When we ...

1. ... suggest that Rav Yosef follows the opinion of Rav Huna, we assume that - Rav Yosef declared even the first animal T'reifah.

2. ... counter that he might even hold like Rav Chisda, we assume that - it was only the last twelve that he declared T'reifah, but not the first one.

3. ... conclude that he must hold like Rav Huna after all, we do so because Rav Chisda would have permitted all the animals, right down to the last one - because (bearing in mind that in his opinion, the neck-bone will not cause the knife to become defected by contact with it any more than the skin of the neck), his reason must be Talinan (we rely on the latter). And by the same token, he will go even further and always rely on the last possibility, namely, that the knife became defected on the neck-bone of the last animal.

8)

(a)Rav Acha b'rei de'Rava told Rav Ashi that Rav Kahana required the knife to be inspected after each Shechitah. When we ...

1. ... suggest that he follows the opinion of Rav Huna, we mean that - if he does not, then should he subsequently find the knife to be defected, all the animals that he Shechted will be declared T'reifah, including the first one.

2. ... counter that he might even hold like Rav Chisda, we mean that - they will all be T'reifah, except for the first one.

(b)Even though we just concluded that according to Rav Chisda, we ascribe the defect to the neck-bone of the last animal - we do not accept that opinion (as it is carrying things a bit too far).

(c)In spite of what we have just said, Rav Kahana really holds - that as long as the Shochet has not used the knife to break bones, even the first animal is T'reifah, like Rav Huna (as we ruled above).

9)

(a)This prompts to ask why the Shochet is not obligated to give his knife to a Chacham for inspection, following the Shechitah of each animal. We only ask it (at this point), on Rav Chisda - according to whom the purpose of inspecting the knife is to permit the Shochet to Shecht the next animal, but not on Rav Huna, who requires the inspection to permit the animal that has already been Shechted (and which is permitted due a Chazakah).

(b)We answer - with the principle Eid Echad Ne'eman be'Isurin (that a person is believed on his own in matters of Isur, and does not require witnesses to substantiate that he did the right thing) ...

(c)... and the Pasuk "al-Pi Shenayim Eidim Yakum Davar" - applies to matters pertaining to Mamon, Nashim and punishments at the hand of Beis-Din ...

(d)... and the Shochet's obligation to show the Chacham his knife before he begins to Shecht is - basically a matter of Kavod Chacham (and not to verify its Kashrus).

10)

(a)Rebbi Shmuel bar Nachmeni Amar Rebbi Yonasan learns from the Pasuk in Tazri'a (in connection with Tzara'as Batim) "Veyatza ha'Kohen min ha'Bayis el Pesach ha'Bayis, Vehisgir es ha'Bayis Shiv'as Yamim" - the principle of Chazakah (that we assume something to be as it was, until a change can be proved).

(b)Rav Acha bar Ya'akov refutes the proof on the grounds that the Pasuk might expect the Kohen - to exit the house walking backwards (to ensure that he sees the mark on the wall right up to the time that he pronounces it Tamei), in which case there will be no Chazakah.

(c)Abaye disagrees with Rav Acha bar Ya'akov on two scores. One of them is the fact that walking out backwards will not fulfill the requirement of "Veyatza min ha'Bayis". The other is that - even if it would, it would not enable him to see a mark behind the door, should it be located there.

(d)He also objects to the suggestion that one could open a window through which the Kohen can ensure that the Tzara'as is still intact and has not diminished to less than the minimum Shi'ur - based on the Mishnah in Nega'im, which declares a house Tahor if the Kohen requires a window to examine the stricken wall.

11)

(a)Rava proves from the Yetzi'ah of the Kohen Gadol from the Kodesh Kodshim on Yom Kipur (who exited backwards) that - exiting backwards is considered Yetzi'ah (refuting Abaye's first objection).

(b)And he counters Abaye's second objection (regarding opening a window in the door) - by restriction the Torah's prohibition to before the Kohen has actually seen the mark, but once he has, it doesn't matter how he goes on to establish the sighting.

(c)The Beraisa learns from the Pasuk there ...

1. ... "Veyatza ha'Kohen el Pesach ha'Bayis" that - the Kohen cannot go home and declare Tamei, the house that he just saw, but that he must do so from the entrance of the stricken house.

2. ... "min ha'Bayis" that - he must leave the house completely before declaring it Tamei (and not do so whilst still standing underneath the lintel.

3. ... "Ve'hisgir es ha'Bayis" that - Bedi'eved, the house will be Tamei, even if he declares it Tamei after arriving at his own house.

(d)Rav Acha reconciles his opinion with this Beraisa - by establishing this last D'rashah where one man is standing on the threshold of the stricken house, who ascertains that the mark has not diminished, and a row of people leading from it to the Kohen's house (see Tosfos DH 'de'Kaymi', pass on the information to the Kohen.