Rava said to Rav Adda bar Ahava: When the Merciful One juxtaposes kosher and non-kosher animals to creeping animals, this is referring to the prohibition of: “You shall not make your souls detestable” (Leviticus 20:25), teaching that they are all included in that prohibition. But with regard to measures the Torah does not juxtapose those animals to creeping animals. For this reason there is no difference between the measure of impurity of carcasses of kosher animals and non-kosher animals.

MISHNA: The blood of one of the eight creeping animals listed in the Torah and their flesh join together to constitute the lentil-bulk measure to impart impurity. Rabbi Yehoshua stated a principle: With regard to any items whose impurity, in terms of degree and duration, and measure to impart impurity, are equal, e.g., two halves of an olive-bulk from two corpses or two animal carcasses or two halves of a lentil-bulk from two creeping animals, they join together to constitute the requisite measure.

Rabbi Yehoshua continued: By contrast, with regard to items whose impurity is equal but their measure is not equal, e.g., a creeping animal and an animal carcass, each of which renders one impure until the evening, but the measure of a creeping animal is a lentil-bulk, whereas that of an animal carcass is an olive-bulk; or items whose measure is equal but whose impurity is not equal, e.g., a corpse and an animal carcass, with regard to which the measure of each is an olive-bulk, but the duration of the impurity imparted by a corpse is one week and the duration of the impurity imparted by an animal carcass is until the evening; or items that are equal neither in terms of their impurity nor in terms of their measure, they do not join together to constitute the requisite measure.

GEMARA: The mishna teaches that the blood of one of the eight creeping animals listed in the Torah and the flesh of those animals join together to constitute the lentil-bulk measure required to impart impurity. Rav Ḥanin says that Rav Zeira says: The blood and flesh join together only if the blood is from the same animal as the flesh, but not if it is from a different animal.

And similarly, Rabbi Yosei bar Rabbi Ḥanina says, in rejection of Rav Zeira’s statement: It is taught in a baraita: The verse states: “These are the impure [hateme’in] to you among all that creep; whoever touches them when they are dead, shall be impure until the evening” (Leviticus 11:31). This plural form of “hateme’in” teaches that they join together to impart ritual impurity. And this applies even to the flesh of a creeping animal and the flesh of another creeping animal, or the flesh of a creeping animal and the blood of another creeping animal, whether they are from one category, i.e., one type of creeping animal, or from two categories of creeping animal.

Rav Yosef says: This is not difficult. Here, the baraita is referring to a case where the half-measure of flesh and the half-measure of blood both came from an entire animal, and therefore the two half-measures combine, due to the significance of an entire animal. There, in the statement of Rav Zeira, he is speaking of a case where the half-measure of flesh and the half-measure of blood each come from part of an animal.

And from where do you say that there is a distinction between a case where the flesh and blood come from an entire animal and a case where they come from part of an animal? From that which is taught in a baraita: In a case where one quarter-log of blood from a corpse was spilled on the floor, and its place was a slope [ketafres], so that the blood trickles down, and someone leaned over so that he covered part of it, he remains ritually pure. If he covered all of it, he is rendered impure.

The Gemara clarifies the halakha: What does the phrase: Part of it, mean in this context? If we say that it is referring to part of the one quarter-log of blood, whereas if it is a full quarter-log then he is impure, that is difficult: But doesn’t Rabbi Ḥanina say that Rabbi Yehuda HaNasi says: If there was exactly one quarter-log of blood in a pot that one stirred without touching the blood, he remains pure, despite the fact that his body must have overshadowed all the blood at the time, and would therefore have had the status of a tent over it. The reason is that some of the blood must have been absorbed into the spoon with which he stirred, and therefore there no longer remains an entire connected quarter-log. This shows that the entire quarter-log must be together, as one unit, in order to impart impurity.

Rather, isn’t it correct to conclude from this baraita that there is a distinction between a case where the blood came from an entire corpse, and where it came from part of a corpse? In other words, if the blood came from one body it need not be together as a single unit, whereas if it came from more than one body, it must all be joined together, as in the case mentioned by Rabbi Yehuda HaNasi. Similarly, with regard to the statements of Rav Zeira and the baraita, here the baraita is referring to a situation where the half-measure of flesh and the half-measure of blood came from an entire animal, and due to the significance of an entire animal the two half-measures combine. There, Rav Zeira is referring to a case where the half-measure of flesh and the half-measure of blood come from part of the animal. The Gemara notes that one should indeed conclude from it that this is the correct distinction.

§ The Gemara relates that Rabbi Matya ben Ḥarash asked Rabbi Shimon ben Yoḥai in the city of Rome: From where is it derived with regard to the blood of creeping animals that it is impure? Rabbi Shimon ben Yoḥai said to him: It is derived from the fact that the verse states: “And these are they that are impure for you among the creeping animals” (Leviticus 11:29). Since a similar phrase already appears in Leviticus 11:31, it is derived from here that the blood of creeping animals is impure.

Rabbi Matya ben Ḥarash’s students said to him in amazement: How wise is Rabbi Shimon ben Yoḥai! Rabbi Matya ben Ḥarash said to them: This source is not his own, as it is a set tradition in the mouth of Rabbi Elazar bar Rabbi Yosei, and Rabbi Shimon ben Yoḥai learned it from him. Rabbi Matya ben Ḥarash provided the background for this claim. As, on one occasion the gentile monarchy issued a decree that the Jewish people may not observe Shabbat, and that they may not circumcise their sons, and that they must engage in intercourse with their wives when they are menstruating.

Rabbi Reuven ben Isterobeli went and cut his hair in a komei hairstyle,which was common only among the gentiles, and he went and sat with the gentiles when they were discussing these three decrees. He said to them: One who has an enemy, does he want his enemy to become poor or to become rich? They said to him: He wants his enemy to become poor. Rabbi Reuven ben Isterobeli said to them: If so, with regard to the Jewish people as well, isn’t it better that they will not perform labor on Shabbat in order that they will become poor? The gentiles said: That is a good claim that he said; let us nullify our decree. And they indeed nullified it.

Again Rabbi Reuven ben Isterobeli spoke to them and said: One who has an enemy, does he want his enemy to become weak or to become healthy? They said to him: He wants his enemy to become weak. Rabbi Reuven ben Isterobeli said to them: If so, with regard to the Jewish people as well, isn’t it better that they circumcise their sons after eight days and thereby cause them to become weak? The gentiles said: That is a good claim that he said, and they nullified their decree.

Once again Rabbi Reuven ben Isterobeli spoke to them and said: One who has an enemy, does he want his enemy to multiply or to decrease? They said to him: He wants his enemy to decrease. Rabbi Reuven ben Isterobeli said to them: If so, with regard to the Jewish people as well, isn’t it better that they do not engage in intercourse with their wives when they are menstruating? The gentiles said: That is a good claim that he said, and they nullified their decree.

A short time later they recognized that Rabbi Reuven ben Isterobeli was a Jew, and they realized that he had fooled them to the advantage of the Jewish people. They therefore arose and reinstated all of their decrees. The Sages then said: Who will go and nullify these decrees?