Introduction to Hilchos She'ar Avot haTum'ah

Included in this text are three positive commandments. They comprise the following:
1) the laws of the impurity of a dead animal;
2) the laws of the impurity of a dead crawling animal;
3) the laws of the impurity of semen.
False deities impart impurity like a dead crawling animal. This impurity is a Rabbinic decree.
These mitzvot are explained in the ensuing chapters.

הלכות אבות הטומאות - הקדמה הלכות שאר אבות הטומאות יש בכללן שלש מצות עשה וזה הוא פרטן:
(א) דין טומאת נבלה
(ב) דין טומאת שרץ
(ג) דין טומאת שכבת זרע
וע"ז מטמאה כשרץ וטומאתה מדברי סופרים
וביאור מצות אלו בפרקים אלו:

1

The carcass of a dead animal is a primary source of impurity. An olive-sized portion of its meat imparts impurity to a person and keilim when touched and to an earthenware container when it enters its inner space. And it imparts impurity to a person when being carried to the extent that his clothes become impure, as is the law regarding a surface on which one rides that contracted impurity from a zav.

What is implied? When a person touches the carcass of a dead animal, he is considered as a primary derivative of impurity. If he touches keilim - even at the same time that he is touching the carcass - they are pure. Similarly, the clothes that he is wearing are pure, for he is a derivative of impurity and a derivative does not impart impurity to keilim.

When, by contrast, one carries the carcass of a dead animal, he imparts impurity to keilim while he is carrying it, as Leviticus 11:28 states: "One who carries their carcasses must launder his garments." Those garments are considered as primary derivatives of impurity. He does not impart impurity to another person or to earthenware containers even when he is carrying the carcass, as we explained in Hilchot Metamei Mishkav UMoshav.

א

הַנְּבֵלָה אָב מֵאֲבוֹת הַטֻּמְאוֹת. כְּזַיִת מִבְּשָׂרָהּ מְטַמֵּא אָדָם וְכֵלִים בְּמַגָּע וּכְלֵי חֶרֶס בַּאֲוִיר. וּמְטַמֵּא אֶת הָאָדָם בְּמַשָּׂא לְטַמֵּא בְּגָדִים כְּמֶרְכַּב הַזָּב. כֵּיצַד. אָדָם שֶׁנָּגַע בִּנְבֵלָה נִטְמָא וַהֲרֵי הוּא רִאשׁוֹן לְטֻמְאָה. וְאִם נָגַע בְּכֵלִים אֲפִלּוּ בִּשְׁעַת מַגָּעוֹ בִּנְבֵלָה הֲרֵי הֵן טְהוֹרִין. וְכֵן כֵּלִים שֶׁעָלָיו טְהוֹרִין לְפִי [שֶׁהוּא] וָלָד וְאֵין וָלָד מְטַמֵּא כֵּלִים. אֲבָל הַנּוֹשֵׂא אֶת הַנְּבֵלָה מְטַמֵּא כֵּלִים בִּשְׁעַת נְשִׂיאָתוֹ שֶׁנֶּאֱמַר (ויקרא יא כח) "וְהַנּשֵֹׁא אֶת נִבְלָתָם יְכַבֵּס בְּגָדָיו". וְאוֹתָן הַבְּגָדִים רִאשׁוֹן לְטֻמְאָה. וְאֵינוֹ מְטַמֵּא לֹא אָדָם וְלֹא כְּלֵי חֶרֶס וַאֲפִלּוּ בִּשְׁעַת נְשִׂיאָתוֹ כְּמוֹ שֶׁבֵּאַרְנוּ בִּמְטַמְּאֵי מִשְׁכָּב וּמוֹשָׁב:

2

These laws apply regarding both the carcasses of a domesticated animal and a wild animal, whether of a species permitted to be eaten or one forbidden to be eaten. If any of these types of animals die, an olive-sized portion of their meat imparts impurity. The ritual slaughter of a kosher domesticated animal or a kosher wild animal purifies it in all circumstances. Even if one slaughtered an ordinary animal in the Temple Courtyard or a consecrated animal outside the Temple Courtyard, they are pure. If a disqualifying factor occurs in the process of ritual slaughter, the carcass is considered like that of an animal that died. It imparts impurity when carried, as stated in Hilchot Shechitah.

ב

אֶחָד בְּהֵמָה וְחַיָּה בֵּין הַמֻּתָּרִין בַּאֲכִילָה בֵּין הָאֲסוּרִין אִם מֵתוּ כֻּלָּן בְּשָׂרָן מְטַמֵּא בִּכְזַיִת. וּשְׁחִיטַת בְּהֵמָה טְהוֹרָה וְחַיָּה טְהוֹרָה מְטַהַרְתּוֹ בְּכָל מָקוֹם. וַאֲפִלּוּ שָׁחַט חֻלִּין בַּעֲזָרָה וְקָדָשִׁים בַּחוּץ הֲרֵי אֵלּוּ טְהוֹרִין. וְאִם אֵרַע פִּסּוּל בַּשְּׁחִיטָה הֲרֵי זוֹ נְבֵלָה וּמְטַמְּאָה בְּמַשָּׂא כְּמוֹ שֶׁבֵּאַרְנוּ בְּהִלְכוֹת שְׁחִיטָה:

3

Ritual slaughter has no effect on the status of a non-kosher domesticated animal or a non-kosher wild animal. Whether one slaughters such an animal, stabs it in the throat, strangles it, or it dies naturally, it is considered as an animal carcass. Flesh from all carcasses - both from kosher species and from non-kosher species can be combined to reach the minimum measure of an olive-sized portion that imparts ritual impurity.

ג

בְּהֵמָה טְמֵאָה וְחַיָּה טְמֵאָה אֵין הַשְּׁחִיטָה מוֹעֶלֶת בָּהּ וְאֶחָד הַשּׁוֹחֲטָהּ אוֹ הַנּוֹחֲרָהּ אוֹ הַחוֹנְקָהּ אוֹ שֶׁמֵּתָה כְּדַרְכָּהּ הֲרֵי זוֹ נְבֵלָה. וְכָל הַנְּבֵלוֹת מִצְטָרְפוֹת לְעִנְיַן טֻמְאָה לִכְזַיִת אֶחָד טְמֵאוֹת וְאֶחָד טְהוֹרוֹת:

4

The marrow of a bone is considered like flesh. The blood of an animal carcass does not impart impurity like an animal carcass. Instead, it is considered as an impure liquid which does not impart impurity to a person or to utensils according to Scriptural Law.

ד

מֹחַ הֲרֵי הוּא כְּבָשָׂר. וְדַם הַנְּבֵלָה אֵינוֹ מְטַמֵּא כִּנְבֵלָה אֶלָּא הֲרֵי הוּא כְּמַשְׁקִין טְמֵאִים שֶׁאֵינוֹ מְטַמֵּא לֹא אָדָם וְלֹא כֵּלִים מִן הַתּוֹרָה:

5

The fat of a kosher animal that died without ritual slaughter is ritually pure, as implied by Leviticus 7:24: "The fat of a domesticated animal that died or the fat of a domesticated animal that was torn to death may be used for any purpose." The license granted by this verse applies to an entity forbidden only because the animal had died or was torn to death. If such fat was made fit to contract impurity due to contact with liquids that convey that status, it is considered as impure food and not as the meat of a dead animal.

Nevertheless, when one touches the fat the surrounds the kidney of a kosher domesticated animal that died without ritual slaughter before it was separated from the kidney, he is impure like one who touches the kidney itself. The rationale is that several strands of flesh from the kidney itself extend into the fat.

With regard to a non-kosher domesticated animal and a wild animal, whether kosher or non-kosher, the same laws apply to both its meat and its fat with regard to ritual impurity. An olive-sized portion imparts impurity to a person and to keilim like the meat of a dead animal.

ה

חֵלֶב בְּהֵמָה טְהוֹרָה שֶׁמֵּתָה טָהוֹר. שֶׁנֶּאֱמַר (ויקרא ז כד) "וְחֵלֶב נְבֵלָה וְחֵלֶב טְרֵפָה יֵעָשֶׂה לְכָל מְלָאכָה וְאָכל לֹא תֹאכְלֻהוּ" מִי שֶׁאִסּוּרוֹ מִשּׁוּם נְבֵלָה וּטְרֵפָה. וְאִם הֻכְשַׁר בְּמַשְׁקִין הַמַּכְשִׁירִין הֲרֵי הוּא כָּאֳכָלִין טְמֵאִין וְאֵינוֹ כִּבְשַׂר נְבֵלָה. וְהַנּוֹגֵעַ בַּחֵלֶב הַחוֹפֶה אֶת הַכֻּלְיָא קֹדֶם הַפְרָשָׁה הֲרֵי זֶה טָמֵא כְּנוֹגֵעַ בַּכֻּלְיָא עַצְמָהּ שֶׁהֲרֵי כַּמָּה חוּטִין נִמְשָׁכִין מִמֶּנָּה בַּחֵלֶב. אֲבָל בְּהֵמָה טְמֵאָה וְהַחַיָּה בֵּין טְהוֹרָה בֵּין טְמֵאָה אֶחָד בְּשָׂרָהּ וְאֶחָד חֶלְבָּהּ לְטֻמְאָה. וּמְטַמֵּא אָדָם וְכֵלִים בִּכְזַיִת כִּבְשַׂר הַנְּבֵלָה:

6

The fat of a ko'i imparts impurity like its meat does, but this impurity is of doubtful status. Therefore terumah and sacrificial foods are not burnt because of it, nor is one liable for karet for entering the Temple or partaking of sacrificial foods after touching it.

ו

הַכְּוִי חֶלְבּוֹ מְטַמֵּא כִּבְשָׂרוֹ וְטֻמְאָתוֹ בְּסָפֵק. לְפִיכָךְ אֵין שׂוֹרְפִין עָלָיו תְּרוּמָה וְקָדָשִׁים וְאֵין חַיָּבִין כָּרֵת עַל טֻמְאָתוֹ וְעַל בִּיאַת הַמִּקְדָּשׁ אוֹ עַל אֲכִילַת קָדָשָׁיו:

7

These are the parts of a carcass that do not impart impurity: the bones, the horns, and the hoofs; this includes even their soft portions that if cut off from a living animal would cause bleeding, the hide, even if has not been processed to use for other purposes, the pieces of flesh that remain attached to the hide when an animal is skinned, the sinews, sauce, and spices cooked with such meat.

When does the above apply? When they were separated from an animal's carcass. If, however, one touches any of these entities while they are still attached to the meat of a carcass, he contracts impurity, provided there is an olive-sized portion of meat. For none of these can be included as part of that required olive-sized portion.

ז

וְאֵלּוּ דְּבָרִים שֶׁאֵין מְטַמְּאִין מִן הַנְּבֵלוֹת. הָעֲצָמוֹת וְהַקַּרְנַיִם וְהַטְּלָפַיִם אֲפִלּוּ עִקָּרָן הָרַךְ שֶׁאִם יַחְתֹּךְ מִן הַחַי יוֹצֵא דָּם. וְהָעוֹר אַף עַל פִּי שֶׁאֵינוֹ מְעֻבָּד. וְהָאָלָל וְהַגִּידִים וְהַמָּרָק וְהַתַּבְלִין שֶׁמִּתְבַּשְּׁלִין עִמָּהּ. בַּמֶּה דְּבָרִים אֲמוּרִים בִּזְמַן שֶׁפֵּרְשׁוּ מִן הַנְּבֵלָה. אֲבָל הַנּוֹגֵעַ בְּאֶחָד מִכָּל אֵלּוּ כְּשֶׁהֵן מְחֻבָּרִין בַּבָּשָׂר הֲרֵי זֶה טָמֵא. וְהוּא שֶׁיִּהְיֶה בַּבָּשָׂר כְּזַיִת. שֶׁאֵין אֶחָד מִכָּל אֵלּוּ מִצְטָרֵף לִכְזַיִת:

8

The pieces of flesh that remain attached to the hide when an animal is skinned whether separated by a wild beast or by a knife should not be considered as part of an olive-sized portion. If the different pieces of flesh were collected and they comprised an olive-sized portion, they impart impurity.

ח

הָאָלָל בֵּין שֶׁפְּלָטַתּוּ חַיָּה בֵּין שֶׁפְּלָטַתּוּ סַכִּין אֵינוֹ מִצְטָרֵף לִכְזַיִת. וְאִם כְּנָסוֹ וְהָיָה בּוֹ כְּזַיִת מְטַמֵּא:

9

These are the parts of animals for which the hide is considered as their meat: the hide of a domesticated pig, the soft hide of a camel hump, the skin of the genital area, the skin of a fetus, and the skin below the fat-tail. Such portions of an animal carcass impart impurity. If one processed them or trod upon them to the extent necessary to process them, they are pure. If one performed a deed that negated their use as meat, they are pure even though he did not trod upon them to the extent necessary to process them.

What is implied? If one used the ear of a donkey as the handle for his basket, it is pure. For how long must one tread on a hide in order to process it? For as long as it takes to walk four millin. What is meant by a soft camel hump? One that was never used for a burden. If a camel reached the age when it was fit to carry burdens, but one did not use it for that purpose or one used it for that purpose before it reached the appropriate age, it is questionable whether its status changes.

ט

וְאֵלּוּ בְּהֵמוֹת שֶׁעוֹרוֹתֵיהֶם כִּבְשָׂרָם. עוֹר חֲזִיר שֶׁל יִשּׁוּב וְעוֹר חֲטוֹטֶרֶת הַגָּמָל הָרַכָּה וְעוֹר בֵּית הַבֹּשֶׁת וְעוֹר הַשְּׁלִיל וְעוֹר שֶׁתַּחַת הָאַלְיָה. הֲרֵי אֵלּוּ מְטַמְּאִין מִן הַנְּבֵלָה. וְאִם עִבְּדָן אוֹ הָלַךְ בָּהֶן כְּדֵי עֲבוֹדָה הֲרֵי אֵלּוּ טְהוֹרִים. וְאִם עָשָׂה בָּהֶן מַעֲשֶׂה שֶׁבִּטְּלָן טְהוֹרִין אַף עַל פִּי שֶׁלֹּא הָלַךְ בָּהֶן כְּדֵי עֲבוֹדָה. כֵּיצַד. אֹזֶן חֲמוֹר שֶׁטְּלָאָהּ לִכְפִיפָתוֹ טְהוֹרָה. כַּמָּה הוּא כְּדֵי עֲבוֹדָה אַרְבָּעָה מִילִין. וְאֵי זוֹ הִיא חֲטוֹטֶרֶת רַכָּה כָּל זְמַן שֶׁלֹּא טָעֲנָה. הִגִּיעַ זְמַנָּהּ לִטְעֹן וְלֹא טָעֲנָה אוֹ שֶׁטָּעֲנָה קדֶם שֶׁיַּגִּיעַ זְמַנָּהּ הֲרֵי זֶה סָפֵק:

10

The following laws apply when one skins the carcass of a domesticated or a wild animal, whether from a kosher species or a non-kosher one, whether it is a small animal or a large animal. If he skins it to use as a mat, as soon as he skins a portion of the hide sufficient to hold onto, i.e., two handbreadths, one who touches the hide that was skinned is pure. Before it is skinned two handbreadths, one who touches the hide is like one who touches meat.

If one skins the animal in order to use its hide for a flask, the hide is considered as connected to the carcass until one skins the entire breast. If one skins an animal from its feet alone, the entire hide is considered as connected. One who touches the hide is like one who touches the meat until the hide is entirely separated from the meat. Similarly, when one skins the hide of crawling animals, the hide is considered as connected until it is skinned in its entirety. Similarly, the hide that is around an animal's neck is considered as connected until it is removed in its entirety.

Any hide that is considered as connected with regard to imparting ritual impurity is also considered as connected with regard to contracting ritual impurity, i.e., if an animal was slaughtered and impurity touched this hide that was connected to the meat, the meat contracts impurity.

י

הַמַּפְשִׁיט נִבְלַת בְּהֵמָה אוֹ חַיָּה בֵּין טְמֵאָה בֵּין טְהוֹרָה בֵּין דַּקָּה בֵּין גַּסָּה. אִם לִשְׁטִיחָה הִפְשִׁיט כֵּיוָן שֶׁהִפְשִׁיט מִן הָעוֹר כְּדֵי אֲחִיזָה וְהוּא שְׁנֵי טְפָחִים הַנּוֹגֵעַ בְּעוֹר זֶה שֶׁהֻפְשַׁט טָהוֹר. וְעַד שֶׁלֹּא הִפְשִׁיט שְׁנֵי טְפָחִים הַנּוֹגֵעַ בָּעוֹר כְּנוֹגֵעַ בַּבָּשָׂר. הִפְשִׁיטָהּ כְּדֵי לַעֲשׂוֹת מִן הָעוֹר חֵמֶת הֲרֵי הָעוֹר חִבּוּר עַד שֶׁיַּפְשִׁיט אֶת כָּל הֶחָזֶה. וְאִם הִפְשִׁיטָהּ מֵרַגְלֶיהָ בִּלְבַד הֲרֵי הָעוֹר כֻּלּוֹ חִבּוּר וְהַנּוֹגֵעַ בָּעוֹר כְּנוֹגֵעַ בַּבָּשָׂר עַד שֶׁיַּפְרִישׁ הָעוֹר כֻּלּוֹ מֵעַל הַבָּשָׂר. וְכֵן הַמַּפְשִׁיט בִּשְׁרָצִים חִבּוּר עַד שֶׁיַּפְשִׁיט כֻּלּוֹ. עוֹר שֶׁעַל הַצַּוָּאר חִבּוּר עַד שֶׁיַּפְשִׁיט כֻּלּוֹ. וְכָל עוֹר שֶׁהוּא חִבּוּר לְטַמֵּא כָּךְ הוּא חִבּוּר לְהִתְטַמֵּא. שֶׁאִם הָיְתָה שְׁחוּטָה וְנָגְעָה טֻמְאָה בְּעוֹר זֶה שֶׁהוּא חִבּוּר נִטְמָא הַבָּשָׂר:

11

When there is a hide that has an olive-sized portion of meat from a carcass on it, if one touches a strand of the hide that extends outward from the meat or the hair on the other side of the hide that is opposite the meat, he contracts impurity. The rationale is that the hide and its hair are considered as "protecting" the meat.

When does the above apply? When the meat was left over by an animal. When it was left over by a knife, it is considered insignificant with regard to the hide if it was thin.

יא

עוֹר שֶׁיֵּשׁ עָלָיו כְּזַיִת נְבֵלָה הַנּוֹגֵעַ בַּצִּיב הַיּוֹצֵא מִמֶּנּוּ וּבִשְׂעָרוֹ שֶׁכְּנֶגְדוֹ מֵאֲחוֹרֵי הָעוֹר נִטְמָא מִפְּנֵי שֶׁהָעוֹר בִּשְׂעָרוֹ שׁוֹמֵר לַבָּשָׂר. בַּמֶּה דְּבָרִים אֲמוּרִים שֶׁפְּלָטַתּוּ חַיָּה. אֲבָל פְּלָטַתּוּ סַכִּין אִם הָיָה מְרֻדָּד בָּטֵל אַגַּב הָעוֹר:

12

When there are two pieces of meat, each half the size of an olive-sized portion on a hide, the hide causes them to be considered as insignificant. They do not impart impurity, neither when touched, nor when carried. The rationale is that any portion of a carcass that does not impart impurity when touched does not impart impurity when carried.

If, however, one skewered two pieces, each half the size of an olive-sized portion, one who carries them is impure because he carried an olive-sized portion of meat from a carcass. One who touches them, by contrast, is pure, because something joined by man is not considered as joined. The liability for carrying the pieces of meat applies provided both pieces are flattened and stuck together so that they are picked up together. If, however, the two half olive-sized portion were separate entities, but held on the same skewer, the person is pure even if he carries them back and forth the entire day.

יב

עוֹר שֶׁיֵּשׁ עָלָיו כִּשְׁנֵי חֲצָאֵי זֵיתִים בְּשַׂר נְבֵלָה הָעוֹר מְבַטְּלָן וְאֵינָן מְטַמְּאִין לֹא בְּמַגָּע וְלֹא בְּמַשָּׂא. שֶׁכָּל שֶׁאֵינוֹ מְטַמֵּא מִן הַנְּבֵלָה בְּמַגָּע אֵינוֹ מְטַמֵּא בְּמַשָּׂא. אֲבָל שְׁנֵי חֲצָאֵי זֵיתִים שֶׁתְּחָבָן בְּקֵיסָם הַנּוֹשְׂאָן טָמֵא שֶׁהֲרֵי נָשָׂא כְּזַיִת וְהַנּוֹגֵעַ טָהוֹר שֶׁאֵין חִבּוּרֵי אָדָם חִבּוּר וְהוּא שֶׁיִּהְיוּ שְׁנֵיהֶן מְרֻדָּדִין וּדְבוּקִין זֶה בָּזֶה עַד שֶׁיִּנָּטְלוּ כְּאֶחָד. אֲבָל אִם הָיָה חֲצִי זַיִת זֶה בִּפְנֵי עַצְמוֹ וְזֶה בִּפְנֵי עַצְמוֹ בְּקֵיסָם אֶחָד אֲפִלּוּ הוֹלִיךְ וְהֵבִיא כָּל הַיּוֹם כֻּלּוֹ טָהוֹר:

13

When the meat of a carcass decomposes, becomes spoiled, and is no longer fit for a dog to eat, it is pure. Accordingly, there is an unresolved doubt whether the netzal of an animal carcass imparts impurity or not.

The following laws apply when the meat from a carcass dries out. If it would return to a moist state and be fit for a dog to eat when left to soak in lukewarm water for an entire day, it imparts impurity. If not, it is pure. It does not even impart impurity like impure foods do.

יג

בְּשַׂר נְבֵלָה שֶׁנִּפְסַד וְהִבְאִישׁ וְנִפְסַל מִלֶּאֱכל הַכֶּלֶב טָהוֹר. לְפִיכָךְ נֶצֶל הַנְּבֵלָה סָפֵק אִם מְטַמֵּא בִּכְזַיִת אִם לֹא. בְּשַׂר נְבֵלָה שֶׁיָּבַשׁ אִם יָכוֹל לִשְׁרוֹת בְּפוֹשְׁרִין מֵעֵת לְעֵת וְלַחֲזֹר לַח וְרָאוּי לַכֶּלֶב מְטַמֵּא וְאִם לָאו טָהוֹר וַאֲפִלּוּ בָּאֳכָלִין טְמֵאִין אֵינוֹ מְטַמֵּא:

14

When the meat of an animal carcass was decomposed at the outset and was not fit for human consumption, it is pure, as can be inferred from Deuteronomy 14:21: "Give it to the stranger in your gate and he will eat it." At the outset, it must be fit for a stranger to eat.

יד

בְּשַׂר נְבֵלָה שֶׁהָיָה סָרוּחַ מֵעִקָּרוֹ וְאֵינוֹ רָאוּי לְמַאֲכַל אָדָם הֲרֵי זֶה טָהוֹר שֶׁנֶּאֱמַר (דברים יד כא) "לַגֵּר אֲשֶׁר בִּשְׁעָרֶיךָ תִּתְּנֶנָּה וַאֲכָלָהּ" עַד שֶׁתִּהְיֶה תְּחִלָּתָהּ רְאוּיָה לְגֵר:

15

A placenta found in an animal carcass is considered as waste matter and feces. It does not impart impurity like a carcass. If the person had in mind to eat it, it is susceptible to the impurity associated with food. The dried milk in the stomach and the liquid milk in the stomach of a carcass are entirely pure.

טו

שִׁלְיָא שֶׁל נְבֵלָה הֲרֵי הִיא כְּפֶרֶשׁ וּכְרֶעִי וְאֵינָהּ מְטַמְּאָה כִּנְבֵלָה. וְאִם חָשַׁב עָלֶיהָ לַאֲכִילָה מִתְטַמֵּא טֻמְאַת אֳכָלִין. הַקֵּבָה וְהֶחָלָב שֶׁל נְבֵלָה טְהוֹרִין מִכְּלוּם:

16

When an animal discharges coagulated blood, even though such a discharge makes it exempt from the laws of the firstborn, it does not impart impurity, neither when touched, nor when carried unless there is the form of a fetus recognizable. The rationale is that it is nullified because there is a majority of other substances that are discharged with it. Therefore, it is pure even though it was initially fit for a stranger to eat together with its mother.

טז

בְּהֵמָה שֶׁשָּׁפְעָה חֲרָרַת דָּם אַף עַל פִּי שֶׁנִּפְטְרָה מִן הַבְּכוֹרָה אֵינָהּ מְטַמְּאָה לֹא בְּמַגָּע וְלֹא בְּמַשָּׂא עַד שֶׁיִּהְיֶה בָּהּ צוּרַת נֵפֶל לְפִי שֶׁהִיא בְּטֵלָה בָּרֹב הַיּוֹצֵא עִמָּהּ. לְפִיכָךְ הִיא טְהוֹרָה אַף עַל פִּי שֶׁהָיְתָה רְאוּיָה לַגֵּר אַגַּב אִמָּהּ:

17

The following laws apply when the carcass of an animal that was not slaughtered became intermingled with that of a slaughtered animal. If the majority of the meat is from the ritually slaughtered animal, the meat from the carcass is considered as insignificant and none of the mixture imparts impurity when touched. If, however, one carries the entire mixture, he contracts impurity.

The reason why the meat of the carcass can be considered insignificant is that it is impossible for the ritually slaughtered meat to be considered as a carcass, but the carcass can become pure if it becomes putrefied. Therefore it can become nullified.

יז

נְבֵלָה שֶׁנִּתְעָרְבָה בִּשְׁחוּטָה אִם רֹב מִן הַשְּׁחוּטָה בְּטֵלָה הַנְּבֵלָה בַּשְּׁחוּטָה וְאֵין הַכּל מְטַמֵּא בְּמַגָּע. אֲבָל אִם נָשָׂא הַכּל נִטְמָא שֶׁאִי אֶפְשָׁר לִשְׁחוּטָה שֶׁתַּחְזֹר נְבֵלָה אֲבָל הַנְּבֵלָה אֶפְשָׁר שֶׁתִּטְהַר כְּשֶׁתִּסְרַח לְפִיכָךְ תִּבָּטֵל: