חולין ט׳Chullin 9

Mishnah 1א׳

הָעוֹר, וְהָרֹטֶב, וְהַקִּפָּה, וְהָאֱלָל, וְהָעֲצָמוֹת, וְהַגִּידִין, וְהַקַּרְנַיִם, וְהַטְּלָפַיִם, מִצְטָרְפִין לְטַמֵּא טֻמְאַת אֳכָלִים, אֲבָל לֹא טֻמְאַת נְבֵלוֹת. כַּיּוֹצֵא בוֹ, הַשּׁוֹחֵט בְּהֵמָה טְמֵאָה לְנָכְרִי וּמְפַרְכֶּסֶת, מְטַמְּאָה טֻמְאַת אֳכָלִין, אֲבָל לֹא טֻמְאַת נְבֵלוֹת, עַד שֶׁתָּמוּת אוֹ עַד שֶׁיַּתִּיז אֶת רֹאשָׁהּ. רִבָּה לְטַמֵּא טֻמְאַת אֳכָלִין מִמַּה שֶׁרִבָּה לְטַמֵּא טֻמְאַת נְבֵלוֹת. רַבִּי יְהוּדָה אוֹמֵר, הָאֱלָל הַמְכֻנָּס, אִם יֶשׁ בּוֹ כַזַּיִת בְּמָקוֹם אֶחָד, חַיָּב עָלָיו:

The hide, the juice, the sediment, the offal, the bones, the sinews, the horns, and the hooves combine [to become the minimum size] to render food impure, but not to impart nevelah [an improperly slaughtered animal of a permitted species] impurity. Similarly, one who slaughters an unclean animal for a non-Jew and it is [still] kicking, it renders food impure. But it does not impart nevelah impurity until it dies or its head is cut off. [The Torah] increased those which render food impure over the amount it increased those which impart nevelah impurity. Rabbi Yehuda says, "Offal which combines, if it has an olive's volume in one place, one is liable for it [for nevelah impurity]."

Mishnah 2ב׳

אֵלּוּ שֶׁעוֹרוֹתֵיהֶן כִּבְשָׂרָן, עוֹר הָאָדָם, וְעוֹר חֲזִיר שֶׁל יִשּׁוּב. רַבִּי יוֹסֵי אוֹמֵר, אַף עוֹר חֲזִיר הַבָּר. וְעוֹר חֲטוֹטֶרֶת שֶׁל גָּמָל הָרַכָּה, וְעוֹר הָרֹאשׁ שֶׁל עֵגֶל הָרַךְ, וְעוֹר הַפְּרָסוֹת, וְעוֹר בֵּית הַבֹּשֶׁת, וְעוֹר הַשָּׁלִיל, וְעוֹר שֶׁתַּחַת הָאַלְיָה, וְעוֹר הָאֲנָקָה וְהַכֹּחַ וְהַלְּטָאָה וְהַחֹמֶט. רַבִּי יְהוּדָה אוֹמֵר, הַלְּטָאָה כַחֻלְדָּה. וְכֻלָּן שֶׁעִבְּדָן אוֹ שֶׁהִלֵּךְ בָּהֶן כְּדֵי עֲבוֹדָה, טְהוֹרִין, חוּץ מֵעוֹר הָאָדָם. רַבִּי יוֹחָנָן בֶּן נוּרִי אוֹמֵר, שְׁמֹנָה שְׁרָצִים יֵשׁ לָהֶן עוֹרוֹת:

[For] these their skin is like their flesh [in regards to impurity]: the skin of a person and the skin of a domestic pig. Rabbi Yose says, "Even the skin of a wild pig." And the skin of the hump of a soft camel, the skin of the head of a soft calf, the skin of the hooves, the skin of the genitals, the skin of the fetus, the skin under the tail, and the skin of the gecko, the crocodile, the lizard, and the sand-lizard [four of the eight types of sherets, small animals, such as insects, reptiles, or rodents, which move by scurrying, creeping, slithering, etc., the vast majority of which are prohibited for consumption]. Rabbi Yehuda says, "The lizard is like a weasel." And all of them which one dressed, or one trampled on for the sake of dressing, are pure, except for the skin of a person. Rabbi Yochanan ben Nuri says, "The eight sheratsim have skin [not like their flesh]."