1. Machlokes if two half-זיתים attached to a hide can combine for tumah

The next Mishnah states that if two half-זיתים of נבילה were attached to a hide, Rebbe Yishmael says: מטמא במשא ולא במגע – it is metamei through carrying, since he carried a full כזית at once, but it is not metamei through touching, because the two pieces are touched separately. Rebbe Akiva says it is not even metamei with משא, as will be explained. Rebbe Akiva agrees בשני חצאי זיתים שתחבן בקיסם והסיטן – regarding two half-זיתים of נבילה which one stuck onto a splinter and moved them, that he is tamei (and he would rule the same for one who touches them). The reason he holds two small pieces attached to a hide are not metamei together is מפני שהעור מבטלן – because the hide nullifies them. Rebbe Ami quoted Rebbe Yochanan saying that Rebbe Yishmael only considers the meat significant if פלטתו חיה – an animal’s bite removed it together with the hide, but פלטתו סכין בטיל – if the skinner’s knife intentionally removed it, it is nullified by the hide and not metamei. Others quoted Rebbe Yochanan saying that even a כזית of meat is nullified if it was intentionally removed during skinning.

1. Machlokes if אין נוגע וחוזר ונוגע, and if אין מאהיל וחוזר ומאהיל

Rebbe Yishmael taught that one who touches two half-זיתים attached to a hide remains tahor. Bar Padda says this is only if he touched the meat מאחריו – from behind (through the hide). אבל מלפניו – But if he touched the meat directly from in front, יש נוגע וחוזר ונוגע – there is transmission of tumah through touching and again touching (i.e., two simultaneous acts of touching the two half-זיתים). [Touching through the hide is not metamei, because he holds a שומר is ineffective for less than a כזית.] Rebbe Yochanan says that even if he touched the two pieces directly, Rebbe Yishmael would rule him tahor, because he holds אין נוגע וחוזר ונוגע. Rebbe Yochanan said that רבי דוסא בן הרכינס holds a similar opinion in a Mishnah which states: anything which is metamei through אהל (i.e., parts of a dead body) which was divided into two pieces, each smaller than the minimum shiur, and were brought together into a house, רבי דוסא בן הרכינס says a person inside remains tahor, because he holds אין מאהיל וחוזר ומאהיל – there is no tumah transmission through making an אהל and again making an אהל, but the Chochomim say he is tamei.

1. Ulla: two half-זיתים of neveilah on a splinter are not metamei with משא

Ulla said that שני חצאי זיתים שתחבן בקיסם – if [one] stuck two half-זיתים on a splinter, אפי' מוליך ומביא כל היום כולו – even if he carries them back and forth all day, he remains tahor. The passuk is written as "נִשָּׂא" – that which is carried, but is read as"נּוֹשֵׂא" – one who carries, teaching:בעינן נושא והוא דנישא בבת אחת – we require that one carries [נבילה], and it is carried as one, not in two pieces each smaller than a כזית. Rav Pappa explains that our Mishnah, which says two half-זיתים can be metamei with משא, is במרודד – where a flattened strip of meat connects the two pieces, enabling them to be carried together.

The Gemara proves that Ulla’s ruling is a machlokes Tannaim: the Tana Kamma says אחד הנוגע ואחד המסיט בלא נישא – both one who touches and one who moves [two half-זיתים of] נבילה meat which cannot be carried as one is tamei, but Rebbe Eliezer says: והוא דנישא – this is only if it can be carried as one.

Siman – Cookie Dough. The ice cream maker, working on the new cookie dough נבלה flavor, was thrilled that he didn’t become tamei from touching a piece of skin with two half-kezaysim of נבלה attached to it, since he didn’t carry it but was dismayed when he heard that he did become tamei from flipping it over and touching the נבלה, because יש נוגע וחוזר ונוגע, and was annoyed at his assistant, who pointed out that, had he put it on a splinter, he could have carried it around all day with no worries.