The Mishnah
כלים א׳Kelim 1
Perek 1 of 30 in Kelim — 9 mishnayot
Mishnah 1א׳
אֲבוֹת הַטֻּמְאוֹת, הַשֶּׁרֶץ, וְשִׁכְבַת זֶרַע, וּטְמֵא מֵת, וְהַמְּצֹרָע בִּימֵי סָפְרוֹ, וּמֵי חַטָּאת שֶׁאֵין בָּהֶם כְּדֵי הַזָּיָה, הֲרֵי אֵלּוּ מְטַמְּאִין אָדָם וְכֵלִים בְּמַגָּע, וּכְלֵי חֶרֶשׂ בַּאֲוִיר, וְאֵינָם מְטַמְּאִין בְּמַשָּׂא:
The Origins of impurity: the sheretz [one of eight creeping creatures, whose identities are debated, and whose carcasses transmit ritual impurity upon contact], semen, that which is rendered impure by a dead body, the metzora [victim of a Divinely inflicted skin disease] while he is in his days of counting, a small amount of purifying water that is not enough to perform the sprinkling ceremony - can render persons and vessels impure through touch, and pottery vessels through the air, but they do not render impure when they are carried.
Mishnah 2ב׳
לְמַעְלָה מֵהֶם, נְבֵלָה, וּמֵי חַטָּאת שֶׁיֶּשׁ בָּהֶם כְּדֵי הַזָּיָה, שֶׁהֵם מְטַמְּאִין אֶת הָאָדָם בְּמַשָּׂא לְטַמֵּא בְגָדִים בְּמַגָּע, וַחֲשׂוּכֵי בְגָדִים בְּמַגָּע:
Higher than these: the nevelah [an animal which died without proper slaughter] and purifying water of which there is enough to perform the sprinkling ceremony, as they render impure a person through carrying and clothing through touch, and without clothes [on an unclothed area of a person], by touch.
Mishnah, Torat Emet 357 edition, via Sefaria — public domain
English: Sefaria Community Translation — CC0