Gemara

(Rav Yehudah citing R. Chanina ben Antignos): Any woman who is Dayah Sha'atah, the law of her Kesem is as if as she (properly) saw blood, except for a girl below the age (at which we expect her) to see blood;

For such a girl, even if her sheet is full of blood we are not concerned.

57b (Beraisa): If a Kesem was found on her body, she is Safek Tehorah, Safek Teme'ah. We consider her Teme'ah. If it was found on her garment, it is Safek Tahor, Safek Tamei. We consider it Tahor.

58a - Questions (R. Yirmeyah): If the blood has one of the following shapes, what is the law? It is a ring, there are many drops, or it is across the width of her thigh.

Answer (Beraisa): If she found a Kesem on her body, Safek Tahor, Safek Tamei, she is Teme'ah.

Suggestion: The Chidush of the Beraisa is even if it is one of these shapes!

Rejection: No, it is in a strIp.

58b (Mishnah - R. Chanina ben Antignos): She may be Toleh up to a Gris...)

(Rav Huna): She may be Toleh up to a Gris, but not a full Gris.

(Rav Chisda): She may be Toleh a full Gris, but not more.

59a (Mishnah - R. Eliezer bar Tzadok): If an Ed was under a pillow... (if blood is in a round shape, she is Tehorah. If it is a streak, she is Teme'ah.)

Question: Do Chachamim argue with R. Eliezer?

Answer #1 (Beraisa): (The extent of) a long Kesem joins (for the Shi'ur of over a Gris), but spots of blood do not join.

This is unlike R. Eliezer. He does not require a Shi'ur for a streak! Rather, we must say that Chachamim taught this. They argue with R. Eliezer.

Rejection: No, the Tana is R. Eliezer. He does not require a Shi'ur for a streak on an Ed, but he requires a Shi'ur for Kesamim.

Answer #2: Rav Yehudah taught that the Halachah follows R. Eliezer.

This implies that there is an argument.

Rishonim

Rambam (Hilchos Isurei Bi'ah 9:6): A Kesem on her body has no Shi'ur, but a Kesem on her garment is Tamei only if it is more than a Gris. If it is less than this, she is Tehorah. If there are many drops, they not join. If it is a long Kesem, it joins.

Rebuttal (Ra'avad): R. Yochanan asked about drops on her body. If there is no Shi'ur, what was his question? Also, the Mishnah taught together her garment below the belt, and her body opposite her Ervah. Regarding all of these, it says that she is Toleh about everything. According to the Rambam, there is no Shi'ur and she is Toleh! This is wrong.

Rambam (9): If a Kesem was found on her body and it is long like a strap, or round, or there were many drops, or the length of the Kesem was along the width of her thigh, or it seems that it seems that it is from below to above, since it is opposite the Ervah, she is Temei'ah. We do not say that had it dripped from her body it would not be like this. We are stringent about any blood found in these places, even though it is a Safek.

Rosh (8:2): "Ka'Shurah" is drops in a line. If not, this is like a strap, which was taught below (to explain the Beraisa in a way that does not answer the question)! The drops are abnormal. If not, why is there a question about them? The Rashbam explains that "ka'Shurah" is several lines. 'Drops' can be in a line, or in a circle. At the end of our Perek we say that ddo not join. That is when they are on a garment, for each drop could be from a louse. We do not attribute blood on her body to a louse. The Safek is because if the blood fell from the place, it would not be in such a shape. This question was not resolved. Some say that we are lenient about Kesamim, and some say that we are stringent, like we tried to prove from the Beraisa. Even though we rejected the proof, it is a flimsy rejection (so we do not rely on it). A strap is the normal way to fall. It seems that the Beraisa elaborated 'Safek Tahor, Safek Tamei - she is Temei'ah', and did not say 'on her body, a Safek is Tamei', for it comes to teach a Chidush.

Poskim

Shulchan Aruch (YD 190:6): We require a Shi'ur for a Kesem on her garment or on her body. Some say that this is only for a Kesem on her garment, but on her body in places for which we are concerned, it has no Shi'ur.

Bach (4): The Tur says that Chachamim did not decree about Kesamim of a girl below the age to see. I disagree. The Gemara said that even if her sheet is full of blood, we are not concerned. It did not say that even if her body is full of blood, we are not concerned! This shows that we are stringent about a Kesem on her body.

Bach (12): Drops on her garment do not join to more than a Gris, but perhaps drops on her body join. The Gemara did not resolve this, therefore we are stringent.

Shach (10): The Bach rules like the latter opinion in Sa'if 8 (below, that drops on her body join). I say that one should not be lenient at all. (Rather, on her body there is no Shi'ur.) The Gemara said 'perhaps it is like a strap.' This connotes like the Rambam. If not, what is the difference between on her garment and on her body?! Tosfos, the Rosh, and Hagahos Maimoniyos citing R. Simchah connote like this.

Gra (16): The Rambam explains that the question was whether the shape proves that the blood is not from her, like it says in Sa'if 9. If not, she is Temei'ah. The Meforshim explain that he asked whether it is like her garment, and drops do not join. This is the latter opinion in Sa'if 8. The Rashba says that on her body is just like on her garment, like the Rambam. The drops are big k'Gris. This is the first opinion in Sa'if 8, which does not distinguish. In practice, the Rashba agrees to the latter opinion in Sa'if 8.

R. Akiva Eiger: Tif'eres l'Moshe says that if she killed a louse, also the Rambam is Metaher up to a Gris, just like when she has a wound on her body. In my opinion, this requires investigation.

Pischei Teshuvah (13): Mahara Brevda says that one should be stringent like the Rambam. Sidrei Taharah and Minchas Yakov say that one who is lenient like the first opinion, like the Bach, does not lose.

Shulchan Aruch (8): If there is no Kesem more than a Gris in one place, even though there are many drops close to each other and if we join then there is more than a Gris, she is Tehorah. We are Toleh each drop on a louse, until there is more than a Gris in one place.

Beis Yosef (DH u'Mah she'Chasav ba'Meh, citing the Rashba): The Ra'avad and Rishonim say that the suggestion 'it is in a strap' was a mere Dichuy. We do not rely on it. Therefore, if there are many drops, she is Temei'ah. The Meforshim explain that R. Yirmeyah asked about many drops that join to more than a Gris. A Beraisa (59a) says that a long Kesem joins, but spots of blood do not join. We can say it discusses drops on her garment, and here we discuss drops on her body. The Ra'avad and Tosfos (58a DH k'Shurah) hold like this. I say that he did not ask whether small drops join. Rather, he discusses drops bigger than a Gris. He asked whether their shape proves that they are not from her. The other Beraisa discusses whether small drops join. The Gemara had not yet discussed the Shi'ur of a Kesem, only where and it what case we are concerned for it. R. Yirmeyah asked about drops, and along the width of her thigh. If he discusses the Shi'ur, he should have asked in the Sugya below regarding the Shi'ur! My Rebbi says so. He asked that since the Beraisa says that small drops do not join, this connotes that one drop more than a Gris is Metamei her! He answered that R. Yirmeyah asked about drops on her garment. It moves around. Blood could come on it from her in many places. This does not apply to her body. (Therefore, drops on her body do not join.) I explained that in every case, they do not join.

Beis Yosef (DH v'Rabbeinu): The Tur wrote Stam like the Rashba in the name of the Ra'avad and Tosfos, that R. Yirmeyah asked whether small drops join, and the question was not resolved, so we are stringent. This is only if they were found on her body. On her garment, they not join, like the Beraisa at the end of our Perek. It seems that the Rosh disagrees. He holds that the question was whether the shape proves that they are not from her, and not about joining. This is like the Rashba and his Rebbi. Also the Rambam holds like this. He is stringent, like the Gemara wanted to prove from the Beraisa. It seems that Rashi agrees, for he explains R. Yirmeyah's question and says that it is normal to fall like a strap.

Shulchan Aruch (ibid.): Some say that this is only when they are found on her garment, but on her body, they join to more than a Gris.

Levush (8): Even the first opinion in Sa'if 6 that there is a Shi'ur even for a Kesem on her body, here he agrees that we do not attribute every drop to a louse. It is normal to squash many lice on her garment or sheet, but not to squash many lice on her body.

Shach (12): This is only according to the first opinion in Sa'if 6. The latter opinion is Metamei a Kesem on her body of any size!

Gra (19): The Poskim were stringent about the question, for the Beraisa connotes that every Safek is Tamei. Also, the rejection said 'perhaps.' It says so in Sa'if 9.

Pischei Teshuvah (16, citing Binas Adam): If a Kesem was found on her sleeve by the folds, and there are drops, if it is not sewn, surely they do not join, for each fold is by itself. Even if they are sewn, this requires investigation, for in any case there is air between them.

Shulchan Aruch (9): If a Kesem is found on her body, if it is long like a strap, or round, or there were many drops, or the length of the Kesem was along the width of her thigh, or it seems that it seems that it is from below to above, since it is opposite the Ervah, she is Temei'ah. We do not say that had it dripped from her body it would not be like this.

Bach (12): According to the Beis Yosef, even less than a Gris on her body is Tamei. Why in Sa'if 8 does he say that some say that on her body they join, and afterwards he Stam cites the Rambam who holds that any on her body is Tamei without any Shi'ur? If we would explain the Rambam the way the Rashba does, that he is Metamei on her body only if it is more than a Gris, but small drops do not join even on her body, he is more lenient even from the lenient opinion in Sa'if 8, which holds that drops on her body join!

Rebuttal (Shach 14): The Rashba cannot understand the Rambam this way. The Rambam (Halachah 6) explicitly said that there is no Shi'ur for a Kesem on her body! Also, how could one derive this from the Rambam? He merely cited the Gemara! After the Beis Yosef brought the Rambam, he cited the Rosh 'who is Metamei less than a Gris on her body, like the Rambam that I wrote above.' The Bach understood that he refers to the Rambam in this Sa'if. This is wrong. If so, the Beis Yosef should have said 'like I wrote b'Samuch (just above)'! Also, 'like the Rambam' connotes that the Rambam is more explicit than the Rosh. The Rosh is more explicit, for the Rambam merely cited the Gemara! Rather, the Beis Yosef discusses the Rambam in Halachah 6. The Beis Yosef connotes that the Rambam's words in this Sa'if are inconclusive. The Rashba did not say that the Rambam requires more than a Gris. He said only that the Rambam explains that the question was not about joining, rather, whether it could drip from the body in this way. The Rashba himself holds that only more than a Gris is Metamei.