BERAISOS CONCERNING NORMAL MANNER OF TRAPPING AND SHINUI
"Normal manner" means digging a hole and placing a trap in it. Shinui means smashing the ground down into the animal's own hole thus burying it.
(R. Shimon ben Elazar): When the Tana Kama permits trapping in a wheat field in the normal manner, it is only when the wheat field borders on a tree field, and the animals could easily cross into the tree field. [This is the Girsa of all the Rishonim, but it is unlike our printed texts. According to our texts, R. Shimon ben Elazar says: When the Chachamim required a Shinui for trapping animals in a wheat field, it was only when it does not border on a tree field, but if it does border on a tree field no Shinui is required.]
Question: What does the Mishnah (above, 6b, 8:b) mean by "repairing"?
(Rav Yosef): Making a makeshift fence of bay branches and palm leaves.
(Beraisa): Placing rocks without mortar.
R. CHISDA'S HETER
(R. Chisda): When the Mishnah forbade making new fences on Chol ha'Mo'ed, it was only referring to garden fences, but a fence for a residential yard may even be made anew (to prevent loss of property through theft).
The Gemara tries to prove R. Chisda's point from a Beraisa, but it is rejected.
Question (Beraisa): A question on R. Chisda is asked from that same Beraisa: The Beraisa says that a wall that leans precariously towards the street may be torn down and rebuilt anew. This implies that only because of danger of collapse may a new wall be built, but not for merely keeping out thieves.
Answer: True, there is a difference between what is permitted to prevent a dangerous collapse and what is permitted to prevent theft, but as follows: In the former case the wall may be torn down and rebuilt, while in the latter case it may only be built anew, but not torn down and then rebuilt.
R. Ashi proves R. Chisda's Heter from the Mishnah, as follows: If the Mishnah were dealing with fences of residential yards, there would be no reason to mention that such a fence may be built during Shemitah. Hence, the Mishnah must be dealing specifically with garden fences, where we might have thought that building such a fence should be forbidden on Shemitah (because it appears as if one is trying to guard his produce for himself, which is forbidden).
MISHNAH: OBSERVING NEGA'IM ON CHOL HA'MO'ED
(R. Meir): The Kohen may observe a Nega on Chol ha'Mo'ed If it is Tahor he should render it Tahor; if not he should remain silent. (The Nega cannot become officially Tamei unless the Kohen declares it to be so.)
(Chachamim): The Kohen should not see any Nega at all on Chol ha'Mo'ed
BERAISA ELABORATING THE MISHNAH
The reason for the Chachamim (who are identified as R. Yosi) is given: He holds that the Kohen may not withhold his opinion on a Nega; if he sees that it is Tamei he must say so. Therefore, he should not see any Nega on Chol ha'Mo'ed, lest he be forced to declare it Tamei and ruin the patient's Simchas Yom Tov.
Rebbi sides with R. Meir in the case of Musgar (a possible Metzora who was confined for seven days to monitor the Nega's growth), and with R. Yosi in the case of a Muchlat (a definite Metzora who now seeks to undergo purification). The explanation for this is that Rebbi agrees in theory to R. Yosi (Tosfos), that the Kohen may not withhold his opinion. Thus, if a Muchlat goes to a Kohen he should not examine him at all, lest he be forced to tell him bad news. A Musgar may be examined, however, because there is no possibility of bad news for him. This will all be explained more fully below (7).
RAVA'S DELINEATION OF THE BERAISA'S DISCUSSION
Rava explains that the disagreement between R. Meir and R. Yosi is limited, as follows:
It does not apply in the case of a Tahor who is about to begin the whole Nega process from the start. There is no possibility of "good news" here and even R. Meir would agree that the Kohen should not examine him.
It does not apply in the case of a Musgar Rishon (one who has finished one week of confinement). This is because no bad news is possible at this point - either the Nega has receded (good news) or it has remained the same and a second Hesger is required (status quo, not bad news). [Obvious question: Perhaps the Nega grew and the patient is now a definite Metzora! See Tosfos.] In this case, then, even R. Yosi would allow the Kohen to examine him.
The disagreement between R. Yosi and R. Meir is thus limited to the case of a Musgar Sheni (and, of course a Muchlat - ed.), who could receive either good news (the Nega is static or healed) or bad news (the Nega has grown and is thus Tzara'as).
DISCUSSION OF REBBI'S POSITION
Above (5:b) we said that Rebbi sides with R. Meir in the case of Musgar, because there is no possibility of bad news there, and with R. Yosi in the case of Muchlat, because there is a possibility of bad news there.
Question: There is another Beraisa that says just the opposite: Rebbi sides with R. Meir in the case of Muchlat, because there is no possibility of bad news there, and with R. Yosi in the case of Musgar, because there is a possibility of bad news there. Which way is true?
Answer: It depends how you look at it. First, the facts:
A Musgar may live anywhere (even in a walled city). [This is Rashi's opinion. It is problematic, but we will use it.] He is also permitted to live with his wife. [The Rishonim quote Rashi as disagreeing with this fact, but we do not have this in our Rashi, so we will accept it as fact.]
A Muchlat is expelled from all walled cities, a form of social ostracism. He may, however, live with his wife.
During the first week after the Nega has been declared healed, the Metzora undergoes what is called Yemei Sefirah, during which time he may live anywhere, but he may not have relations with his wife. (This type of person will heretofore be referred to as a Sofer.)
Back to the answer to question 7:b. According to the first Beraisa Rebbi held that a person values the company of his wife more than the company of the public. Thus, a Musgar does not care if he becomes a Muchlat, for in either case he may live with his wife. (Although a Muchlat must leave town, this does not bother him so much.) A Muchlat (who may live with his wife), however, would be saddened if he became a Sofer (who may not live with his wife). Therefore, Rebbi held that a Musgar may be examined by the Kohen (he has nothing to lose), but a Muchlat may not be examined by the Kohen (he may hear bad news, that he has become a Sofer). According to the second Beraisa Rebbi held that a person values the company of the public more than the company of his wife. Thus, a Musgar (who may live wherever he wants) would be saddened to become a Muchlat (who must leave town), although his status vis-a-vis his wife would be unchanged. A Muchlat (who must live out of town) would be thrilled to become a Sofer (who may live wherever he wants), although he has to separate from his wife. Therefore, Rebbi held that a Muchlat may be examined by the Kohen (he has nothing to lose and everything to gain), while a Musgar may not be examined by the Kohen (he may hear bad news, that he has become a Muchlat).
BIBLICAL SOURCES FOR ABOVE FACTS
Is a Metzora permitted to live with his wife?
During Sefirah he is definitely prohibited to live with his wife, as it says, "He shall sit stay outside his tent," "tent" meaning wife.
(R. Yehudah) (text should really say "Rebbi"): Since the verse says "seven days" it implies that it is limited only to the seven days of Sefirah, and does not apply to a Muchlat.
(R. Yosi b'Rebbi Yehudah): If the Sofer cannot live with his wife, Kal va'Chomer a Muchlat may not. [Note: The entire previous section was assuming like Rebbi, not like R. Yosi b'Rebbi Yehudah.]
How do we know that the Kohen has the power to keep the Nega from being declared Tamei? In other words: How do we know a Kohen can withhold his opinion (according to R. Meir) or can refrain from inspecting a possible Nega (according to R. Yosi)?
(R. Yehudah): It says, "On the day when it is seen on [the Metzora]..." implying that there are certain days when a Metzora is not seen. These days are Chol ha'Mo'ed and a newlywed's week of Sheva Berachos.
(Rebbi): It says, "The Kohen shall tell them to empty out the house before the Kohen comes... so that everything in the house should not become Tamei." If one may delay seeing the Nega for purpose of convenience (preventing the household articles from becoming Tamei), then Kal va'Chomer he can delay for the purpose of a Mitzvah (preventing sadness on a holiday).
What's the difference between these two derivations?
(Abaye): No practical difference.
(Rava): There is a difference, as follows: Rebbi assumed that just as the Kohen may delay seeing a house-Nega for purpose of convenience so may he delay seeing a body-Nega for purpose of convenience. (Hence he made the Kal va'Chomer that delay must certainly be permitted for a Mitzvah.) R. Yehudah would disagree with this step, because a house-Nega is a Chidush (an exceptional law that does not fit in with the general framework of Halachah), because stones and plain wood normally cannot become Tamei. Since it is a Chidush one cannot derive anything about a body-Nega from it. The reason Rebbi did make this step was because there are two relevant verses here, and he held that between the two of these verses this conclusion may be drawn.