Bekhorot 23a

לְרַבִּי אֱלִיעֶזֶר מָה תְּהֵא עֲלֵיהֶן? יֹאכְלוּ נִקּוּדִין, אוֹ קְלָיוֹת, אוֹ יִלּוֹשׁוּ בְּמֵי פֵירוֹת, אוֹ תִּתְחַלֵּק לְעִיסּוֹת, וּבִלְבַד שֶׁלֹּא יְהֵא כְּבֵיצָה בְּמָקוֹם אֶחָד. וְאָמַר עוּלָּא: מָה טַעַם? גְּזֵירָה שֶׁמָּא יָבִיא קַב חוּלִּין טְמֵאִים מִמָּקוֹם אַחֵר וְקַב וְעוֹד מִמִּין זֶה, סָבַר אֱיבַטְּלִינְהוּ בְּרוּבָּא, וְכֵיוָן דְּאִיכָּא הַאי מַשֶּׁהוּ — מָצָא מִין אֶת מִינוֹ וְנֵיעוֹר.

according to Rabbi Eliezer, what will be with them? Let them be eaten dry or roasted, or kneaded with fruit juice, or divided into small batches, provided that there is not an egg-bulk of volume in a single batch. And Ulla says: What is the reason that the mixture may not be allowed to come in contact with water, despite the fact that it is entirely non-sacred? It is a rabbinic decree, lest one bring a kav of non-sacred, impure produce from some other place and take a kav and a little more from this mixture. Then he will think to himself: I will nullify the kav of impure produce with the majority of pure produce from the mixture. But since there is some amount of impure produce in the mixture, the type that was nullified found its own type and is revived in its impure state.

אֲמַר לֵיהּ: אִם טוּמְאָה עוֹרֶרֶת טוּמְאָה, טׇהֳרָה עוֹרֶרֶת טוּמְאָה?

Abaye said to Rav Dimi: That proof is not conclusive. Even if impurity revives impurity, as in the case of teruma where the kav of produce is impure, why should it be assumed that purity revives impurity, as is suggested with regard to the fish brine, where the water in the pot is pure?

אֵיתִיבֵיהּ: אֵפֶר כָּשֵׁר שֶׁנִּתְעָרֵב בְּאֵפֶר מִקְלֶה, הוֹלְכִין אַחַר הָרוֹב לְטַמֵּא, וְאִי רוּבָּא אֵפֶר מִקְלֶה הוּא — לָא מְטַמֵּא. וְאִי אָמְרַתְּ: טוּמְאָה כְּמַאן דְּאִיתֵיהּ דָּמֵי, נְהִי דִּבְמַגָּע לָא מְטַמֵּא — לְטַמֵּא בְּמַשָּׂא!

Abaye raised an objection to the opinion of Rabbi Yirmeya from a mishna ( Para 9:7): If the ashes of a red heifer, which impart ritual impurity to the priests involved in its ritual and are fit for sprinkling on someone impure with impurity imparted by a corpse, became intermingled with regular burned ashes, we follow the majority in order to determine whether or not the mixture is impure. And therefore, if the majority is composed of the regular burned ashes, the mixture does not impart impurity. Abaye explains the objection: And if you say nullified impurity is considered like an item that is nevertheless present in the mixture and can be revived, then although the mixture does not impart impurity through physical contact as it is assumed that one touches the majority, let it impart impurity through carrying due to the ashes of the red heifer.

הָא אִיתְּמַר עֲלַהּ, אָמַר רַבִּי יוֹסֵי בְּרַבִּי חֲנִינָא: טָהוֹר מִלְּטַמֵּא בְּמַגָּע, אֲבָל מְטַמֵּא בְּמַשָּׂא.

Rav Dimi responded: In fact, it was stated with regard to that mishna that Rabbi Yosei, son of Rabbi Ḥanina, says: The mixture is pure in the sense that it does not impart impurity through contact, but it does impart impurity through carrying.

וְהָאָמַר רַב חִסְדָּא: נְבֵילָה בְּטֵילָה בִּשְׁחוּטָה, שֶׁאִי אֶפְשָׁר לִנְבֵילָה שֶׁתֵּיעָשֶׂה שְׁחוּטָה. נְהִי דִּבְמַגָּע לָא מְטַמֵּא, לְטַמֵּא בְּמַשָּׂא!

Abaye responded: But doesn’t Rav Ḥisda say: If meat from an animal carcass, which imparts ritual impurity, was mixed with the meat of a slaughtered animal, the meat from the carcass is nullified by the meat of the slaughtered animal in the event that the ritually pure meat constitutes a majority. The reason is that it is impossible for a carcass to become a slaughtered animal, i.e., a ritually slaughtered animal can never have the status of a carcass with regard to impurity. Abaye explains the difficulty: Granted that it does not impart impurity through contact, but if the impurity is considered present to some extent let the mixture impart impurity through carrying.

אֲמַר לֵיהּ: אַתּוּן בִּדְרַב חִסְדָּא מַתְנִיתוּ לַהּ, אֲנַן בִּדְרַבִּי חִיָּיא מַתְנֵינַן לַהּ. תָּנֵי רַבִּי חִיָּיא: נְבֵילָה וּשְׁחוּטָה בְּטֵילוֹת זוֹ בָּזוֹ, וְאִיתְּמַר עֲלַהּ, אָמַר רַבִּי יוֹסֵי בְּרַבִּי חֲנִינָא: טָהוֹר מִלְּטַמֵּא בְּמַגָּע, אֲבָל מְטַמֵּא בְּמַשָּׂא.

Rav Dimi said to Abaye: You learned the mishna according to the interpretation of Rav Ḥisda, but we learned it according to the interpretation of Rabbi Ḥiyya, as Rabbi Ḥiyya teaches: With regard to meat from an animal carcass and meat from a slaughtered animal, one nullifies the other, depending on the majority. And it was stated with regard to this ruling that Rabbi Yosei, son of Rabbi Ḥanina, says: If the majority is from a slaughtered animal the mixture is pure in the sense that it does not impart impurity through contact, but it does impart impurity through carrying.

וְהָא דִּתְנַן: רַבִּי אֱלִיעֶזֶר בֶּן יַעֲקֹב אוֹמֵר: בְּהֵמָה גַּסָּה שֶׁשָּׁפְעָה חֲרָרַת דָּם — הֲרֵי זוֹ תִּקָּבֵר, וְנִפְטְרָה מִן הַבְּכוֹרָה. וְתָנֵי רַבִּי חִיָּיא: אֵינָהּ מְטַמְּאָה לֹא בְּמַגָּע וְלֹא בְּמַשָּׂא. אַמַּאי? דִּנְהִי בְּמַגָּע לָא מְטַמֵּא, תְּטַמֵּא בְּמַשָּׂא! אִישְׁתִּיק.

Abaye raised another difficulty: And that which we learned in our mishna contradicts your opinion, as Rabbi Eliezer ben Yaakov says: In the case of a large animal that expelled a mass of congealed blood, that mass must be buried, and the animal is exempt from having any future offspring counted a firstborn. And Rabbi Ḥiyya teaches with regard to this ruling: That mass does not impart ritual impurity, neither through physical contact nor through carrying. But why? If Rav Dimi is correct, then granted it does not impart impurity through contact, but let it nevertheless impart impurity through carrying. Rav Dimi was silent in response.

דִּלְמָא, וַדַּאי שָׁאנֵי הָכָא, דְּהָוְיָא לַהּ טוּמְאָה סְרוּחָה. הָנִיחָא לְבַר פְּדָא, דְּאָמַר: טוּמְאָה חֲמוּרָה עַד לְגֵר, וְטוּמְאָה קַלָּה עַד לְכֶלֶב, הָא לָא חַזְיָא לְגֵר. אֶלָּא לְרַבִּי יוֹחָנָן דְּאָמַר:

The Gemara asks: Why was Rav Dimi silent? Perhaps the halakha is different here, as it is decayed impurity, since an animal carcass that has rotted does not impart impurity at all. The Gemara comments: This works out well according to the opinion of bar Padda, who says: An item with severe ritual impurity, such as that of a nonviable newborn, imparts impurity to substances until it is rotted to the degree that it is no longer fit to be consumed by a gentile who observes certain mitzvot [ ger toshav ], who is permitted to consume it; but an item with light impurity, which transmits impurity only by contact, imparts impurity to substances until it is no longer fit to be eaten by a dog. And as this congealed mass is not fit to be eaten by a ger toshav it does not impart impurity. But according to Rabbi Yoḥanan, who says: