The Gemara asks: In what way is this case different from that which is taught in a baraita: With regard to two women who were occupied with one slaughtered bird, and the bird contained only an amount of blood capable of producing a stain as big as a sela coin, and blood the size of a sela was found on this woman and blood the size of a sela was found on that woman, they are both impure, despite the fact that the blood of one of them can be attributed to the bird. Likewise, in the case of Rav Sheshet the lender should be impure as well, as she might not have examined the robe properly. The Gemara answers: There it is different, as there is an additional sela.

The Sages taught in a baraita: In the case of a woman who wore three robes, one on top of the other, that had been examined by her for blood stains, and she subsequently found a stain on one of the robes, if she can attribute the blood on the robe to an external source, she may attribute it to that source, and she is pure. And this is the halakha even if the stain was on the lower robe, closest to her skin. But if she cannot reasonably attribute the blood to an external factor she may not attribute it to an external factor, and she is impure, and this is the halakha even if the stain was on the upper robe.

The baraita elaborates: How so? If she passed through a marketplace of butchers, where blood could have sprayed on her clothes, she may attribute a stain on her garment to the butchers and she is pure, even if the stain was on the lower robe. If she did not pass through a marketplace of butchers or anywhere else with a lot of blood, then even if the stain was on the upper robe she may not attribute the blood to an external source and she is impure.

MISHNA: And a woman who discovers a blood stain on her body or her garment may attribute its existence to any matter to which she can attribute it: If she slaughtered a domesticated animal, an undomesticated animal, or a bird; or if she was occupied with the removal of blood stains from the garments of other women or from her own garment, from any source, such as blood that originated from a wound elsewhere on her body or even her own menstrual blood from a prior menstrual cycle; or if she sat alongside others who were occupied with removing blood stains; or if she killed a louse; in all of these cases, that woman may attribute the blood stain to it.

How large a stain may a woman attribute to a louse? Rabbi Ḥanina ben Antigonus says: It can be up to the area of a split bean. And she may attribute the stain to a louse even if she does not remember that she killed it. And she may attribute the blood stain to her son or to her husband in a case where one of them is near her and has a wound. Furthermore, if the woman herself has a wound, even if the wound scabbed over and is no longer bleeding, but it can reopen and bleed, that woman may attribute the blood stain to that wound.

There was an incident involving one woman who came before Rabbi Akiva. She said to him: I saw a blood stain. Rabbi Akiva said to her: Perhaps there was a wound on your body? She said to him: Yes, there was a wound and it healed. He said to her: Was it perhaps a wound that could reopen and bleed? She said to him: Yes it was. And Rabbi Akiva deemed her ritually pure.

Rabbi Akiva saw his students looking at each other, wondering why he ruled leniently in this case. Rabbi Akiva said to them: What in this matter is difficult in your eyes? The reason I ruled this way is that the Sages did not state the matter of the impurity of blood stains in order to be stringent; rather, they instituted this impurity in order to be lenient, as it is stated: “And if a woman has an issue, and her issue in her flesh shall be blood” (Leviticus 15:19), from which it is derived that by Torah law, “blood” deems her impure, but not a stain. Impurity from a blood stain was instituted by the Sages, and they rule leniently in any case where the stain can be attributed to another source.

With regard to an examination cloth that was placed beneath the pillow and blood was found on the cloth, and it is unclear whether it is the blood of an examination or the blood of a louse that was crushed beneath it, if the stain is round the woman is ritually pure, as an examination to determine whether a woman is menstruating would not leave a round stain. If the stain is elongated the woman is ritually impure; this is the statement of Rabbi Eliezer, son of Rabbi Tzadok.

GEMARA: The mishna teaches that a woman who discovers a blood stain on her body or her garment may attribute its existence to any matter to which she can attribute it. The Gemara notes: We learn in the mishna that which the Sages taught explicitly in a baraita: An incident occurred involving a blood stain found on a woman’s garment, and Rabbi Meir attributed it to an eye salve [bekilor] that the woman had previously handled, and likewise, Rabbi Yehuda HaNasi attributed a stain to the sap of a sycamore tree the woman had touched.

§ The mishna teaches: Or if she was occupied with the removal of blood stains from the garments of other women or from her own garment, from any source, such as blood that originated from a wound elsewhere on her body or even her own menstrual blood from a prior menstrual cycle; or if she sat alongside others who were occupied with removing blood stains. The Gemara infers: If she knows for certain that she sat alongside those occupied with removing blood stains, yes, she may attribute blood to this source. But if she does not know for certain that she sat alongside those who were removing blood stains, but knows only that she was in the same area as they were, she may not attribute blood to this source.

Again the Gemara comments: We learn in the mishna that which the Sages taught explicitly in a baraita: If a woman passed through a marketplace of butchers and it is uncertain whether blood from the marketplace sprayed on her or whether it did not spray on her, she may attribute a stain to the butchers. But if she is uncertain whether she passed by the marketplace or whether she did not pass by, she is deemed impure and may not attribute it to that source. In this case as well, only if she is certain that she was in a circumstance to which she can attribute the blood may she attribute it to that cause.

§ The mishna teaches that if she killed a louse she may attribute the blood stain to it. The Gemara infers: If she killed a louse, yes, she may attribute blood to it, but if she did not kill a louse she may not attribute blood to it. The Gemara asks: Whose opinion is expressed in the mishna? The Gemara answers that it is the opinion of Rabban Shimon ben Gamliel, as it is taught in a baraita: If a woman killed a louse before finding blood, she may attribute blood to it. If she did not kill a louse she may not attribute blood to it; this is the statement of Rabban Shimon ben Gamliel. And the Rabbis say: Both in this case and in that case she may attribute blood to a louse.

Rabban Shimon ben Gamliel said there is a difficulty with regard to both his opinion and that of the Rabbis: According to my statement, that a woman may attribute a stain only to a creature she actually killed, there is no limit; and according to the statement of my colleagues, who rule that she may attribute a stain to a louse even if she had not killed one, there is no end.

Rabban Shimon ben Gamliel explains: According to my statement, there is no limit to the size of the stain she found, as she is impure even if it is as small as a mustard seed. Consequently, you have no woman who is pure to her husband, as you have no bed of any sort on which there are not several drops of blood of a louse. Since I rule that a woman may attribute blood to a louse only if she previously killed one, all women will be in a state of impurity to their husbands.

By contrast, according to the statement of my colleagues there is no end to the advantage their ruling provides to women, because if their ruling is accepted you have no woman who is not pure to her husband, as you have no sheet of any sort on which there are not several blood drops, and every woman can attribute all these drops to a louse, even if she had not killed one.

Rabban Shimon ben Gamliel continues: But the statement of Rabbi Ḥanina ben Antigonus appears to be more correct than my statement and their statement, as Rabbi Ḥanina ben Antigonus would say: How large a stain may a woman attribute to a louse? It can be up to the area of a split bean. And therefore we concede to his opinion and accept his statement. The Gemara asks: And according to the opinion of the Rabbis, who say that a woman may attribute blood to a louse whether or not she killed one, how large can the stain be? After all, some stains are far bigger than those produced by a louse. Rav Naḥman bar Yitzḥak says: She may attribute a stain to a bedbug, which has more blood than a louse, and this applies to any stain whose size is up to the width of a lupine seed.

The Gemara continues to discuss the matter of the bedbug. The Sages taught in a baraita: This bedbug, its length is equal to its width, and its taste is like its foul smell. A covenant is made with it, i.e., it is a law of nature, that anyone who squeezes it will smell its foul odor. The Gemara explains with regard to which halakhot these characteristics of the bedbug were mentioned. The fact that its length is equal to its width was stated with regard to the matter of stains, i.e., if a stain is found whose length is the same as its width, one may attribute it to the blood of a bedbug even if the stain is larger than the area of a split bean.

The statement that its taste is like its foul smell is applicable with regard to the matter of the partaking of teruma, the portion of the produce designated for the priest, as we learned in a mishna (Terumot 8:2): Or if he tasted the taste of a bedbug in his mouth, which is prohibited for consumption, this person must spit out the contents of his mouth, despite the fact that it is generally prohibited to waste teruma. How does he know that there is a bedbug in his mouth? He knows because its taste is like its foul smell. And still, how does he know the smell of a bedbug? In answer to this question the baraita explains that one does not err with regard to the smell of the bedbug, as a covenant is made with it that anyone who squeezes it will smell its foul odor, and therefore it is a well-known smell.

The mishna teaches that a woman may attribute a blood stain as having come from another entity and remain pure. In this regard Rav Ashi says: In the case of a town in which there are pigs, one need not be concerned for stains found on the body or clothes of a woman living there. Since pigs wander the streets and often have stains of blood on them, and their living areas attract bugs of all kinds, any blood stain found on a woman can be attributed to the pigs. Rav Naḥman bar Yitzḥak said: And this town of Dukeret, where there are many slaughterhouses, garbage heaps, and bugs, is considered like a town in which there are pigs.

§ The mishna teaches: How large a stain may a woman attribute to a louse? Rabbi Ḥanina ben Antigonus says: It can be up to the area of a split bean. The Gemara notes that the meaning of the statement of Rabbi Ḥanina ben Antigonus is a matter of dispute among the Sages. Rav Huna says: If the stain was the size of a split bean she may not attribute it to the blood of a louse; if it was less than the size of a split bean she may attribute it to the blood of a louse. And Rav Ḥisda says: Even if it was the size of a split bean she may still attribute it to the blood of a louse; but if the stain was more than the size of a split bean she may not attribute it to the blood of a louse.

The Gemara suggests: Let us say that these Sages disagree with regard to the matter of: Up to and including. As Rav Huna maintains that the term: Up to, means: Up to the measure but not including the measure, and since Rabbi Ḥanina ben Antigonus said that a stain can be up to the area of a split bean, this does not include the size of a bean itself. And Rav Ḥisda maintains that the term means: Up to and including the measure.

The Gemara responds: Rav Huna could say to you that there are instances where the term means up to and including the measure, and there are instances where it means up to and not including the measure. And both here, where it means up to and not including the measure, it is intended as a stringency, as in the statement of Rabbi Ḥanina ben Antigonus; and there, where it means up to and including the measure, it is likewise intended as a stringency.

And Rav Ḥisda could say to you that in general I will say to you that when it leads to a stringency, we say that the term: Up to, means up to and including the measure, whereas if it leads to a leniency we do not say so. And here, with regard to stains, I interpret the term in this manner despite the fact that it entails a leniency, in accordance with the opinion of Rabbi Abbahu. As Rabbi Abbahu says: All measures of the Sages must be interpreted stringently, except for the measure of a split bean as a standard for stains of blood found on a woman’s clothing, which is interpreted leniently. Therefore, even if the stain is exactly the size of a bean the woman remains pure.

Some say this halakha as a distinct matter, not specifically as an explanation of the mishna: Rav Huna says the area of a split bean is considered the same as the area of greater than a split bean. And Rav Ḥisda says the area of a split bean is considered the same as the area of less than a split bean. And these two amora’im disagree with regard to the matter of up to, whether it means including or not including the measure itself, as discussed in this case here, with regard to stains. The Gemara raises an objection: