Mikvaos, Chapter 8, Mishnah 3. Our mishnah continues the discussion of tumas keri. Beyond the Torah's own law, Chazal established cases in which a person is treated as a baal keri mi'drabbanan out of suspicion that a trace of keri was present even without a clear emission. This mishnah presents three such topics: unusual droplets during urination, a man who dreamt at night, and a woman who has a discharge some time after relations.
The opening case is "hamatil tipin avos mitoch ha'amah": a person from whom thick, weighty drops emerged in the course of urinating. Such a person is tamei, and it does not matter whether the drops appeared as the urination began or as it finished, since drops of that consistency are closer in character to keri itself. The mishnah credits this ruling to "divrei Rebbi Elazar Chasma", Rebbi Elazar Chasma, whose view serves as the Tanna Kamma of our mishnah.
The mishnah then turns to the man who had a nighttime experience: "hamharher balaylah", one who dreamt at night that he had relations with a woman, "ve'amad", and he arose, "umatzah besaro cham", and found that his flesh in the relevant place was warm. The ruling is tamei, out of concern that there was in fact an emission and that it was rubbed away or dried up before he noticed it.
Peletas zera and the viability of the zera
The mishnah now takes up peletas zera: a woman who, some while after relations, has a discharge that may still contain zera from that union. Zera retains its power to transmit tumah only for a bounded period of time, and the tana'im differ as to how long that period lasts.
According to the first view, "hapoletes zera beyom hashlishi tehorah": should the discharge occur on the third day following relations, she remains tehorah. This tanna maintains that the zera keeps its potency for two days, and once the third day arrives it has become nisrach, degraded and inert, so it can no longer transmit tumah. To this Rebbi Elazar ben Azaryah attaches the rule of "miktzas hayom kekulo", that a portion of a day is treated as the entire day, and he applies it at both ends of the reckoning: relations that occurred at the very close of a day still make that day count in full, and the day of the discharge is likewise counted in full from the instant it begins.
In practical terms: relations that took place on Sunday shortly before sheki'ah already establish Sunday as day one; Monday is day two; and once Tuesday has begun, we are already in the third day, so a discharge at that point leaves her tehorah.
Rebbi Yishmael takes a different approach: "pe'amim sheheim arba onos, pe'amim sheheim chamesh, pe'amim sheheim sheish". The measure is not a fixed number of days but shifts with the circumstances, sometimes four onos, sometimes five, sometimes six. An onah in the usage of the Mishnah is one half of the twenty four hour cycle, either a night or a day; every full day thus contains two onos, and reckoned in sha'os zemaniyos an onah runs approximately twelve hours.
How the three counts arise:
- Where the act took place during Sunday's daytime, just before sheki'ah, any discharge until day four begins renders her tamei. Monday and Tuesday are what remain, two full days, and that yields four onos.
- Where it took place as Sunday's night was ending, her tumah extends only until leil revi'i sets in, and the tally is five onos: Sunday's daytime portion together with Monday and Tuesday.
- Where it took place bitchilas leil rishon, right as Motzei Shabbos began, one arrives at six onos.
"Rebbi Akiva omer le'olam chamesh", Rebbi Akiva holds it is always five onos, since in his view the measure is sixty hours from the time of relations.
There is an additional view that our mishnah does not record, cited in the Gemara in Shabbos, on daf peh vav amud beis: the Chachamim measure a flat seventy two hours, counted from when the relations took place until the discharge, without any attention to how those hours are divided between days and nights. This is the position we follow in halacha, as codified in Yoreh Deah, siman kuf tzaddi vav.
So this mishnah moves from the visible signs during urination, to the suspicion raised by a dream at night, to the precise timetable governing peletas zera, in each case measuring how far the concern for keri extends.