Niddah 68: Presumptive Status of Ritual Im/Purity and Intermediate Days

To conclude yesterday's conversations, the rabbis consider the halacha regarding a woman who washes her hair before immersion in the mikvah.  Hair washing should be done immediately before immersion, but if immersion is to happen at the end of Shabbat, hair washing cannot take place first for it would be too late in the day to then immerse before being permitted to her husband that same night.  The rabbis rule that a woman must wash her hair and immerse on the same evening unless that is not possible, in which case she is permitted to immerse the following day.

A new Mishna teaches several cases to examine the concept of niddah:

• A woman who examines herself on the seventh day and sees no blood and then immerses in the mikvah without checking herself again at twilight is considered to be ritually pure from the time of examination until the time that she examines herself again to find blood, even if that is only several days after immersion

• A woman who examines herself on the seventh day and finds blood but immerses anyway on the eve of the eighth day is considered to be ritually impure from the point that she found blood until the time that she examines herself again and finds herself to be ritually impure - anything that she touched over that time is also ritually impure

• A woman who examines herself on the morning of the seventh day and finds no blood but then finds blood several days later, her presumptive status is of ritual purity between examinations but she is considered to have imparted ritual impurity to anything that she touched for a twenty-four hour period from examination to examination

• If that last woman has a fixed menstrual cycle, she is considered to be ritually pure from the time she saw blood (there is no retroactive status of ritual impurity)

• Rabbi Yehuda rules stringently, saying that a woman is presumed to be ritually impure if she does not examine herself after mincha on the seventh day following the start of menstruation

• the rabbis rule more leniently, saying that even after only two days of menstruation and then finding blood, a woman is deemed ritually pure between examination and immersion 

In the Gemara, Rav and Levi argue about whether the first woman is a definite greater zava or an uncertain greater zava.  The rabbis debate the presumptive status of a woman who has not checked herself for blood at many different times following the first seven days of one's period.  For people who have never in their lives had a period, they are very intent on describing these facts.

We are introduced to a new Mishna.  It teaches that the zav and zava must examine themselves on each day for seven clean days before purification in a mikvah. Those who are ritually pure on the first day and the seventh day but did not check themselves over the middle days are presumed to be ritually pure by Rabbi Eliezer.  Rabbi Yehoshua says that they must count another seven clean days following the seventh day.  Rabbi Akiva says that they have counted only the seventh day and they must count six more days.

The Gemara begins to explore whether or not a seminal emission during the intermediate days will transmit renewed ritual impurity to a zav.  The rabbis also consider how a zava might be different from or similar to a zav when considering the implications of finding menstrual blood during the intermediate days between counting days.