and blood emerged through the womb, i.e., vaginally, during the three days preceding the birth. And Rabbi Shimon conforms to his line of reasoning, that a caesarean birth is a full-fledged birth, and therefore the blood that emerged prior to the birth is ritually pure, and the Rabbis conform to their line of reasoning, that a caesarean birth is not halakhically considered a birth, which means that the blood which emerged beforehand is considered the blood of ziva, and is ritually impure.

Rav Yosef objects to this explanation: One difficulty is that according to this interpretation, the latter clause of the baraita is superfluous, as the dispute recorded there is identical to that of the first clause. And furthermore, the words: From there, in the phrase: The blood that emerges from there, indicate that this is referring to a place already mentioned in the baraita, i.e., the place from which the offspring emerged, which is the abdominal incision of the caesarean section, not the vagina.

Rather, Rav Yosef said that this is the explanation of the latter clause of the baraita: It is referring to a situation where both the offspring and blood emerged through the incision in the abdomen. It is in such a case that the first tanna deems the blood which emerged impure and Rabbi Shimon deems it pure.

And the matter with regard to which they disagree is whether or not the location of a woman’s source, i.e., her uterus, is ritually impure. One Sage, the first tanna, holds that the location of a woman’s source is ritually impure, and therefore any blood that emerges from it, regardless of how it came out of her body, is impure as well. And one Sage, Rabbi Shimon, holds that the location of a woman’s source is pure, and blood that emerges from there is also pure. Only uterine blood which emerges vaginally is impure.

§ Reish Lakish says: According to the statement of the one who deems the blood impure, the first tanna, he deems the woman impure as well, as though it were blood of menstruation. Likewise, according to the statement of the one who deems the blood pure, Rabbi Shimon, he deems the woman pure as well. But Rabbi Yoḥanan says: Even according to the statement of the one who deems the blood impure, the first tanna, he deems the woman pure.

And Rabbi Yoḥanan follows his standard line of reasoning here, as Rabbi Yoḥanan said in the name of Rabbi Shimon ben Yoḥai: From where is it derived that a woman does not become impure due to menstruation unless the flow of blood emerges from her nakedness, i.e., genitalia? As it is stated: ''And a man who lies with a woman having her flow, and shall uncover her nakedness, he has made naked her source'' (Leviticus 20:18) This teaches that a woman is not impure due to menstruation unless the flow emerges from her nakedness.

Reish Lakish says in the name of Rabbi Yehuda Nesia: If a woman’s source, i.e., her uterus, became dislodged and fell out of her body onto the ground, she is ritually impure, as it is stated: ''Because your foundation was poured out, and your nakedness was uncovered'' (Ezekiel 16:36). The word ''foundation'' alludes to the uterus, and the verse is referring to it after it has been ''poured out,'' i.e., detached, as an uncovering of nakedness, which indicates that it is still a source of impurity even after it has been detached from its place.

The Gemara asks: To what kind of impurity is this woman subject in this situation? If we say that she is subject to the impurity of seven days of menstruating women, that is impossible, as the Merciful One states in the Torah that such impurity is caused by ''blood'' (Leviticus 15:19), and not a piece of flesh. Rather, she is subject to impurity that lasts until the evening, as a result of the surface of her body having come into contact with the uterus, which is a source of impurity.

Rabbi Yoḥanan says: In the case of a woman’s source that discharged two whitish, clear, pearl-like [margaliyyot] drops, she is impure. The Gemara asks: To what kind of impurity is this woman subject in this situation? If we say that she is subject to the impurity of seven days of menstruating women, that is impossible, as the mishna (Nidda 19a) states that there are five distinct colors of ritually impure blood in a woman, but no more, and pearly white is not one of those colors. Rather, she is subject to impurity that lasts until the evening, as a result of her body having come into contact with a discharge from the uterus, which is a source of impurity. And this is the halakha specifically if there were two drops, but if there was only one such drop she is not impure, as I can say that the drop came from elsewhere, not from the uterus.

§ The mishna teaches: All women become ritually impure with the flow of blood from the uterus into the outer chamber, i.e., the vagina, as it is stated: ''And her issue in her flesh shall be blood'' (Leviticus 15:19). The Gemara asks: What exactly is the outer chamber? Reish Lakish says: Any place which can be seen when a little girl sits with her legs spread. When the blood reaches that area in the vagina, the woman becomes ritually impure.

Rabbi Yoḥanan said to Reish Lakish in objection: That place is considered exposed even with regard to contact with the carcass of a creeping animal. If one comes into contact with the carcass of a creeping animal he becomes impure. This is the halakha only if the animal touches a part of the body that is exposed, not an internal cavity such as the inside of the mouth. Since the area of the vagina described by Reish Lakish is considered an exposed part of the body for the purposes of the impurity imparted by the carcass of a creeping animal, it should not be necessary for the mishna to derive the halakha of her impurity from the expression ''in her flesh.'' Rather, Rabbi Yoḥanan says: The term outer chamber extends until the area between the teeth-like projections inside the vagina.

A dilemma was raised before the Sages: Is the area between the teeth-like projections itself considered as internal, which would mean that blood there would not render the woman impure, or as external? Come and hear a resolution, as Rabbi Zakkai teaches a baraita: The term outer chamber extends to the area between the teeth-like projections, but the area between the teeth-like projections themselves is considered as internal.

It was taught in a baraita that a woman becomes impure when the blood reaches the place of threshing, which is a euphemism. The Gemara asks: What is the meaning of this euphemism, the place of threshing? Rav Yehuda says: It is referring to the place in the vagina where the penis threshes, i.e., reaches, during intercourse.

§ The Sages taught in a baraita: It is written concerning a menstruating woman: ''And if a woman has an issue, and her flow in her flesh shall be blood, she shall be in her menstruation seven days'' (Leviticus 15:19). The term ''in her flesh'' teaches that she becomes impure while the blood is still inside her flesh just as when the blood emerges outside her body. I have derived only that this applies in the case of a menstruating woman. From where is it derived that it applies to a zava as well? The same verse states: ''Her flow [zovah] in her flesh.''

From where is it derived that this also applies to a woman who discharges semen after intercourse? The same verse states the apparently superfluous term ''shall be.'' And Rabbi Shimon says: In the case of discharging semen, it is sufficient for her to be like the man who engaged in intercourse with her: Just as the man who engaged in intercourse with her does not become impure until the source of impurity, the semen, emerges outside his body, so too, she does not become impure until her source of impurity, the semen, emerges outside her body. It does not render her impure while it is still inside her body.

The Gemara asks: And does Rabbi Shimon in fact hold that it is sufficient for her to be like the man who engaged in intercourse with her? But isn’t it taught to the contrary in a baraita: The verse states: ''The woman also with whom a man shall lie carnally, they shall both bathe themselves in water, and be impure until the evening'' (Leviticus 15:18). Rabbi Shimon said: And what does this verse come to teach us? If it teaches with regard to one who comes into contact with semen that they are impure, it is already stated below (Leviticus 22:4): ''Or a man from whom the flow of seed goes out,'' from which it is derived that coming into contact with semen renders one impure.

Rather, this verse is necessary because in the case of intercourse the contact with the source of impurity occurs in a concealed part of the body, and contact with impurity by a concealed part of the body generally does not render one impure. But here it is a Torah edict that the woman does become impure in this manner. This baraita proves that according to Rabbi Shimon a woman is rendered impure by semen even when it is inside her body.

The Gemara answers that this is not difficult. Here, this second baraita is dealing with a woman who engages in intercourse, whereas there, the first baraita is dealing with a woman who discharges semen after intercourse. It is only during the act of intercourse that a woman becomes impure due to the semen. If she later discharges semen, she does not become impure, according to Rabbi Shimon, until the semen leaves her body and touches her on the outside.

The Gemara objects: But in the case of a woman who discharges semen, one can derive that she is impure due to the fact that she engaged in intercourse prior to the discharge. The Gemara answers: Rabbi Shimon is referring to a case where she immersed herself, thereby purifying herself from the impurity from her intercourse, and she subsequently discharged semen.

The Gemara asks: Is this to say that in the case of a woman who engages in intercourse it is sufficient for her to simply immerse herself, and then she is in a state of impurity only until evening? But didn’t Rava say: A woman who engages in intercourse is prohibited from partaking of teruma, even if she is married to a priest, for the entire three days following the intercourse, as it is impossible for her not to discharge semen throughout this period, and teruma may not be consumed by one who is impure?

The Gemara answers: Here we are dealing with a case where others immersed the woman while she was still in bed, and she remained there. If she remains lying down, it is possible for her not to discharge semen following intercourse, and the immersion after intercourse purifies her. The Gemara asks: By inference, one can conclude that when Rava said that a woman is in a constant state of impurity for three days after intercourse, he was referring to a case where she walked to the ritual bath by foot and immersed herself. But if so, perhaps while she was walking she released all the semen in her body even before the three days were over, and therefore will not subsequently become impure.