Answer (Beraisa): "(One who touches) its Nevelah" becomes Tamei, but not one who touches skin that does not have a k'Zayis of meat on it;
Suggestion: Perhaps one who touches the skin opposite the meat does not become Tamei!
Rejection: "He will become Tamei."
Question: What does this mean? (We said that one who touches the skin is not Tamei!)
Answer: The Beraisa is abbreviated. It means as follows;
"Its Nevelah" excludes skin that does not have a k'Zayis of meat on it, but joins the skin to comprise a k'Zayis;
Suggestion: Perhaps even if it has a k'Zayis of meat on it, one who touches the skin opposite the meat does not become Tamei. The skin is not even like a handle (to impart Tum'ah)!
Rejection: "He will become Tamei."
(Mishnah): A Yad (a handle for a food or Kli) that is not a Shomer brings Tum'ah (to the food, if Tum'ah touches the Yad) and transfers Tum'ah (from the food to other food), but it does not join (to the Shi'ur needed for Tum'ah);
A Shomer, even if it is not a Yad, brings and transfers Tum'ah, and joins (for Tum'ah);
Anything that is neither a Yad nor Shomer does not bring nor transfer Tum'ah.
Question: Where does the Torah mention Yados?
Answer #1: "... When (Sheratzim) will (touch) produce, it will be Tamei to you." We expound "to you", for all your needs. This includes Yados (what you need to hold the produce).
Answer #2: "... When an animal will die, that is to you (for food, i.e. of a Tahor species)", to you, for all your needs. This includes Yados;
These two verses teach that Yados bring and transfer Tum'ah;
A Kal va'Chomer teaches that a Shomer does this. No verse is needed!
A Yad does not protect (the food), yet it brings and transfers Tum'ah. All the more so, a Shomer (which protects, brings and transfers Tum'ah)!
Question: If so, why do we need a verse to teach about Shomrim?
Answer: We must say that it teaches that they join (to the food to comprise the Shi'ur for Tum'ah).
Question: Perhaps we should say that a Yad only brings Tum'ah and a Shomer even transfers Tum'ah, but a Yad does not transfer Tum'ah, and Shomrim do not join!
Answer: That is unreasonable. If a Yad brings Tum'ah to a food that was never Tamei, all the more so it transfers Tum'ah from the food!
EXTRA SOURCES FOR YADOS
Question: Perhaps a Yad only transfers Tum'ah and a Shomer even brings, but a Yad does not bring and Shomrim do not join?
Answer #1: The Torah mentions an extra Yad (to teach that Yados also bring; therefore, the verse of Shomer is needed only to teach that it joins);
"(If a rodent falls into) an oven, it will be broken... (they will be Tamei) for you" - for all your needs (to include a Yad to hold the oven).
Question: Of the three verses of Yados, which are extra?
Answer #1: The Yados of Nevelah and oven are extra, since they can be derived from the Yad of seeds (i.e. food).
Rejection: They cannot be derived, because Tum'as Ochlim is more prevalent (even a Rishon l'Tum'ah is Metamei food, and Shomrim join for Tum'as Ochlim).
Answer #2: The Yados of Nevelah and food are extra, since they can be derived from the Yad of an oven.
Rejection: They cannot be derived, because an oven is Mekabel Tum'ah from its interior and is Metamei its interior (without touching).
Answer #3: The Yados of food and oven are extra, since they can be derived from the Yad of Nevelah.
Rejection: They cannot be derived, because a Nevelah can be Metamei people, and through Heset (moving it), and Tum'ah emanates from it.
Answer #4: We cannot learn from any one to the others. One of them is extra, it can be derived from the other two.
Question: Which is extra?
Answer #1: The Yad of food is extra. It can be derived from the others.
Rejection #1: It cannot be derived, because a Nevelah or oven does not need Hechsher (preparation to receive Tum'ah), but food does.
Objection (Rav Huna brei d'Rav Yehoshua): Also an oven must be completed to receive Tum'ah. This is like Hechsher!
Rejection #2: Rather, it cannot be derived, because they are Metamei without touching (a Nevelah through Heset, and an oven is Metamei its interior), unlike food.
Answer #2: The Yad of oven is extra. It can be derived from the others.
Rejection: It cannot be derived, because Nevelah and food are both foods.
Answer #3: The Yad of Nevelah is extra. It can be derived from the others.
Since it is not needed for Nevelah, it may be used to teach about Yados in general (that they also bring Tum'ah).
Therefore, when the Torah teaches about Shomrim, it must be that they join.
Rejection: The sources (Yados of oven and seeds) are not Metamei man. We cannot learn more than the sources! (We need the Yad of Nevelah to teach that it can be Metamei man.)
THE DIFFERENCE BETWEEN SHOMRIM AND YADOS
Answer #5: None of the Yados are extra. The verse teaching about a Shomer for Nevelah is extra;
It cannot teach that it joins (for Tum'as Nevelah). We learned (1:c:1) that it does not!
It need not teach that it is Metamei like the Nevelah. A Kal va'Chomer (from Yados) teaches this! (It need not teach about bringing Tum'ah to the Nevelah. A Nevelah is Tamei by itself.)
Since it need not teach about Shomer Nevelah, it must teach about Yad Nevelah.
We already have a source that a Yad is Metamei like a Nevelah. Rather, it must teach that in general, Yados bring Tum'ah;
The verse of Shomrim of food ("on any Zera Zeru'a") teaches that a Shomer joins (for Shi'ur Tum'ah).
Objection: Rather than saying that Shomer Nevelah teaches about (general) Yados. We should use it to teach that (general) Shomrim bring Tum'ah!
The verse of Shomrim of food would teach that a Shomer joins;
There is no source that Yados bring Tum'ah!
Answer #2 (to question a): The verses of Yados discuss bringing Tum'ah, so we cannot say that Yados are only Metamei.
Question: What do we learn from the verse of Shomer Nevelah?
Answer: It teaches about itself.
Question: What does it teach?
It cannot teach that it joins. We learned that it does not!
It need not teach that it brings Tum'ah and it is Metamei. A Kal va'Chomer (from Yados) teaches this!
Answer: Really, it teaches that it brings Tum'ah and it is Metamei;
Even though a Kal va'Chomer teaches this, the Torah also wrote a verse that teaches it.
Question: Why do we use the verse of Shomer of food to teach that a Shomer joins? (Perhaps it teaches the same thing that we learned from the Kal va'Chomer!)
Answer: When we can learn something new from the extra verse, we do not say it teaches the same thing we can learn from a Kal va'Chomer.
Answer (to Objection k:4 - R. Chaviva): Because Shomer Nevelah is (only) like a Yad (it does not join for Shi'ur Tum'ah), we use it to teach about Yados.
Question #1 (Rav Yehudah bar Yishmael - Mishnah): The Pitma (point opposite the stem) of a pomegranate joins (for Shi'ur Tum'ah), but the surrounding hairs do not.
The only source for Shomrim was "Zera Zeru'a." The Pitma is not planted!
Question #2 (Mishnah): Skin, Rotev, spices... join for the Shi'ur of Tum'as Ochlim.
These are not planted. Why do they join?
Answer #2 (To Question 3:e, 117b): We learn about Shomrim from "Al Kol Zera Zeru'a Asher Yizare'a" - these three words teach Shomrim of (things that grow from) seeds, trees, and (things that do not grow from the ground, e.g.) meat, eggs and fish.
(Rav): Yados bring and transfer Tum'ah, but not Hechsher. (If water touches the Yad, the food is not Huchshar);
(R. Yochanan): They also bring Hechsher.
Question: What do they argue about?
Answer: The argument could be based on reasoning, or on how to expound "Al Kol Zera Zeru'a... ":
They could argue about the verse. Rav applies (Yados, which is learned from) the verse to what precedes it (Tum'ah), but not to what precedes what precedes it (Hechsher);
R. Yochanan applies the verse also to what precedes what precedes it.
They could argue based on reasoning. R. Yochanan holds that Hechsher is the beginning of Tum'ah (so Yad also applies to Hechsher);
Rav holds that Hechsher is not the beginning of Tum'ah (so we have no source that Yad applies to Hechsher).
Support (for R. Yochanan - Beraisa): Just like Yados bring Tum'ah and are Metamei, they also bring Hechsher;
Just like produce receives Tum'ah only after it is uprooted, also Hechsher is only after it is uprooted.
(Rav): Yad does not apply to less than a k'Zayis of food. Shomer does not apply to less than k'Ful (the volume of a bean);
(R. Yochanan): A Yad works for less than a k'Zayis. A Shomer works for less than k'Ful.
Question (Beraisa): (If there are two bones from a Mes, and each holds half a k'Zayis of flesh,) if part of each bone without the flesh was brought into a house, the house is Tamei;
Yehudah ben Nekusa says, they cannot join to be a k'Zayis.
Summation of question: How will Rav establish the Beraisa?
If the bones are Yados (the meat is on them), why are Chachamim (the first Tana) Metamei the house? (Rav says that Yad does not apply to less than a k'Zayis!)
If the bones are Shomrim (the meat is marrow inside them), why is Yehudah Metaher? (Shomrim bring Tum'ah!)