Why does R' Yosi ben Zimra go to such great lengths to connect tzara'as with lashon ha-ra - why not just bring a source from Miriam who received tzara'as moments after the story of isha kushis (which according to some, was a criticism of Moshe's abstinence from Tzipora)?
Yehuda Salamon, Bronx, New York
1. The Panim Yafos (Rav Pinchas ha'Levi Horowitz, the author of Sefer Hamakneh on Kidushin and Sefer ha'Hafla'ah on Kesuvos) on the Chumash at the end of Parshas Tazria explains that the Gemara here wants to stress that the punishment for Lashon ha'Ra is that the speaker becomes a "Metzora Muchlat" -- he becomes a totally tamei Metzora and not merely a Metzora Musgar, one who must wait for a week to see if the Tzara'as spreads or becomes weaker. Since, for a woman, there is no difference between being a Metzora Muchlat and a Metzora Musgar, the Gemara could not have brought a source from Miriam.
2. The proof that the laws of Muchlat and Musgar are the same for a woman is from the Mishnah which the Gemara here cites. The Mishnah says that the only distinction between Muchlat and Musgar is "Peri'ah" (the requirement to let one's hair grow) and "Perimah" (the requirement to tear one's clothing). However, the Mishnah in Sotah (23a) states that a woman does not perform Peri'ah and Perimah. It therefore follows that there is no difference between Musgar and Muchlat for a woman.
3. We now can understand why Rebbi Yosi ben Zimra has to use this chain of three words, "Atzmis," "li'Tzemisus," "la'Chalutin"; he is trying to prove, by arriving at the word "la'Chalutin," that Lashon ha'Ra causes the speaker to become a Metzora Muchlat. To show what the difference between Muchlat and Musgar is he must cite a Mishnah which refers only to a male Metzora, and he cannot cite a proof from Miriam.
Kol Tuv,
Dovid Bloom