- The laws of discovered graves for removal and inspection
This Daf consists of several unrelated Mishnayos, where the halachah changes from before a fact is established to afterwards. The Mishnah states: המוצא מת בתחילה מושכב כדרכו נוטלו ואת תפוסתו – One who discovers a corpse for the first time in this place, lying normally, he may remove it with its surrounding earth. Because it is buried alone, there is reason to believe it was buried temporarily, and may be moved. The same applies to two discovered graves. If he found three, buried at intervals matching a Jewish burial ground, הרי זו שכונת קברות – it is a graveyard zone, i.e., intentionally buried, and none can be moved. Furthermore, he must inspect the area for other possible burial chambers up to twenty amos away. Based on the language of the Mishnah, Rav Yehudah excludes the following cases from the law of the Mishnah: a known grave (it does not count towards three graves), someone killed, and someone buried in a sitting position or his head between his thighs. The reason for these last two cases is because the position of burial indicates that it may be a Gentile. A Baraisa adds the case of an incomplete body. (Rishonim suggest that this is a halachah leMoshe miSinai, and that this is the reason for the case of someone killed).
- Safek negaim which are ruled leniently
The next Mishnah states: כל ספק נגעים בתחילה טהור – All doubts of negaim in the beginning, are ruled tahor, עד שלא נזקק לטומאה – as long as he has not been confirmed tamei. The Rosh explains this to refer to a case where two people, or even one, display two negaim of different sizes, and the second week they are both the same larger size. (The smaller one, having spread, should cause confirmed tzaraas). Because it is unknown which nega has grown, and no nega has yet been confirmed, both are declared tahor. The Mishnah continues: משנזקק לטומאה ספקו טמא – Once he is confirmed tamei, his safek is ruled tamei (in a case where it is unknown which nega reverted to its original size). The Gemara suggests a source for the Mishnah, but proves it cannot be. Instead, it is the source for Rebbe Yehoshua, who said that a nega which is unknown if the white spot preceded the white hair (which would be tamei), or the white hair preceded the white spot (which is tahor), is ruled tahor.
- בשבעה דרכים בודקין את הזב עד שלא נזקק לזיבה
The next Mishnah states: בשבעה דרכים בודקין את הזב עד שלא נזקק לזיבה – A zav is examined in seven ways, as long as he has not been confirmed for [tumas] zivah, meaning if he has not yet experienced a second discharge (which makes him tamei for seven days). The Mishnah lists food, drink, carrying a load, jumping, illness, seeing or thinking of something that arouses him, as activities that may have externally caused the zivah. משנזקק לזיבה אין בודקין אותו – Once he has been confirmed for tumas zivah (meaning he experienced two discharges without external causes), he is not examined, and a third discharge will require a korban regardless of its cause. (Also, a later discharge will interrupt his seven clean days, regardless of cause). Rebbe Nassan provides the source: והזב את זובו – “And one who has a flow of zivah,” [whether male or female], לראיה שלישית איתקש לנקיבה – for the third flow, a male is compared to a female, whose zivah is metamei her regardless of cause. Rebbe Eliezer argues in a Baraisa and holds that a zav is examined for the third discharge as well, and only a fourth discharge is tamei (to interrupt clean days) regardless of cause. The Gemara explains the machlokes.