TUM'AH D'RABANAN OF BLOOD
(Mishnah - Beis Shamai): Blood of a Nochris, and Dam Tohar of a Metzora'as are Tehorim;
Beis Hillel says, they are Teme'im like her spit and urine (i.e. when they are wet).
Beis Shamai says, if a Yoledes did not immerse, her Dam Tohar is Tamei like her spit and urine;
Beis Hillel says, it is Tamei wet or dry.
Beis Shamai agrees that if she was Yoledes b'Zov, it is Tamei wet or dry.
(Gemara) Question: Doesn't Beis Shamai agree with the following Beraisa?!
(Beraisa): "Dabru El Bnei Yisrael... Ki Yihyeh Zav" -- mid'Oraisa, Zivah (of a man or woman) applies only to Bnei Yisrael, but Chachamim decreed that Nochrim are like Zavim (or Zavos).
Answer: Beis Shamai agrees with it (regarding spit and urine), but we cannot be Metamei her blood!
If we will say that it is Tamei wet or dry, this is like Tum'ah mid'Oraisa of a Yisraelis. (People will think that it is mid'Oraisa, and they will burn Terumah or Kodshim due to it!)
If we will say that it is Tamei only if it is wet, people will think that this leniency of blood applies also to Tum'ah mid'Oraisa of a Yisraelis!
Question: Why does Beis Shamai admit that we decreed about a Nochris' spit and urine? The same concerns apply!
Answer: Since we are Metaher her blood, people realize that Tum'ah of her spit and urine is only mid'Rabanan.
Question: Why doesn't Beis Shamai decree about her blood, and be Metaher her spit and urine, to reveal that Tum'ah of her blood is only mid'Rabanan?
Answer: Spit and urine are more common than blood, therefore they decreed about them.
TUM'AH MID'RABANAN OF ZOV AND KERI
(Rava): Even Beis Shamai is Metamei a Nochri's Zov. Even Beis Hillel is Metaher his semen.
Even Beis Shamai is Metamei his Zov. Since we are Metaher his semen, people realize that his Zov is Tamei only mid'Rabanan;
Even Beis Hillel is Metaher his semen, in order that people will realize that his Zov is Tamei only mid'Rabanan, so they will not burn Terumah or Kodshim (Gra's text - bring a Korban for Tum'as Mikdash or Kodshim) due to it.
Question: Why aren't we Metamei his semen and Metaher his Zov, to reveal that Tum'ah of his semen is only mid'Rabanan?
Answer: We decreed about his Zov, for it comes without cause, but semen comes only through a cause (the Ever becoming warmed).
Support (Beraisa): If semen of a Yisrael exuded from a Nochris, it is Tamei;
If semen of a Nochri exuded from a Yisraelis, it is Tahor.
Suggestion: It is fully Tahor.
Rejection: No, it is Tahor mid'Oraisa, but it is Tamei mid'Rabanan.
Support (Beraisa): Semen of a Yisrael is Tamei anywhere, even inside a Nochris;
Semen of a Nochri is Tahor anywhere, even inside a Yisraelis, unless (drops of his) urine is mixed with it.
Question: This is no support. Perhaps a Nochri's semen in a Yisraelis is Tahor mid'Oraisa, but Tamei mid'Rabanan!
Answer: The Beraisa teaches that if his urine is mixed in, it is Tamei, i.e. mid'Rabanan. This implies that if his urine is not mixed in, it is Tahor even mid'Rabanan.
(Beraisa): Semen of a Yisrael is Tamei anywhere, even inside a Nochris.
Suggestion: This resolves Rav Papa's question!
Question (Rav Papa): If semen of a Yisrael is inside a Nochris, is it Tamei?
Rejection: No. Rav Papa knew that within three days, it is Tamei (as if was in a Yisraelis). He asks about after three days:
Perhaps semen putrefies (and loses its Tum'ah) in a Yisraelis after three days, for the bodies of Yisraelim are warm, for they are fearful about Mitzvos. A Nochris is cool, so the semen does not putrefy so quickly;
Or, perhaps bodies of Nochrim are equally warm, for they eat Shekatzim u'Remashim (insects and swarming creatures)?
This question is not resolved.
DAM TOHAR OF A METZORA'AS
(Mishnah - Beis Shamai): Dam Tohar of a Metzora'as is Tahor...
Question: What is Beis Hillel's reason (to be Metamei)?
Answer (R. Yitzchak): "La'Zachar" includes Mayanos of a Metzora. "Vela'Nekevah" includes Mayanos of a Metzora'as;
Question: Which Mayanos of a woman are included?
Suggestion: It includes other Mayanos (that also men have).
Rejection: Surely, if they are Teme'im in a man, they are also Teme'im in a woman!
Answer: It includes Dam Tohar. (We already know that her other bloods are Teme'im.)
Beis Shamai argues that we cannot learn from a man to a woman, for a Metzora is more stringent than a Metzora'as. He must do Peri'ah (let his hair grow) and Perimah (tear his clothing), and he is forbidden to have Bi'ah.
Beis Hillel agrees with this. However, the Torah could have taught Mayanos of a Metzora'as, and we would have learned those of a Metzora (from a Kal va'Chomer);
Since we do not need "la'Zachar" to include Mayanos of a Metzora, we use it to include Dam Tohar of a Metzora'as (even though blood is not a proper Mayan, it drips out without accumulating).
Opinion #1: Beis Shamai does not learn from women to men, for there is a stringency of women. Women become Zavos even though Ones, but men do not become Zavim though Ones.
Beis Hillel holds that a stringency of Zivah does not refute a Kal va'Chomer regarding Tzara'as.
Beis Shamai holds that any stringency regarding Tum'ah can refute the Kal va'Chomer.
Opinion #2: Beis Shamai needs "la'Zachar" to teach that any male, even a minor, can become a Zav;
Beis Hillel learn this from "Zos Toras ha'Zav."
ZOV OF A BOY
Question (Rav Yosef citing Reish Lakish): If a boy (less than nine) saw one sighting of Zov, does the Zov have Tum'as Maga (of touching)?
Perhaps "Zos Toras ha'Zav va'Asher Tetzei Mimenu Shichvas Zera" teaches that a man's first sighting of Zov is Tamei only if his semen is Tamei (he is above nine);
Or, since if he will see a second sighting (on the same day or the morrow) the two sightings join to make him a Zav, even the first sighting has Tum'as Maga!
Answer (Rava): "V'Zos Toras ha'Zav" applies whether he is small (below nine) or an adult. (For this law, above nine is an adult);
Just like an adult's first sighting of Zov is Tamei, also a child's.