ב איתיביה נמצא על שלה אתיום טמאין וחייבין בקרבן נמצא על שלה לאחר זמן טמאין מספק ופטורין מן הקרבן ותני עלה וחייבין באשם תלוי הא מני רבי אליעזר היא
2 - This, too, is according to R'Eliezer. Rab Nahman said in the name of Rabbah B'Abbuha, who delivered it in the name of Rab: If there were before a person two pieces, one heleb and the other permitted fat, and he ate of one of them and does not know of which he ate, he is liable; if there was only one piece about which there was a doubt whether it was heleb or permitted fat, and he ate it, he is exempt. Said Rab Nahman: Rab's reason is that in the case of two pieces [the presence of] the forbidden substance is established, in the case of one piece [the presence of] the forbidden substance is not established. What is the practical difference between this reason that the forbidden substance is established and the one stated above that it is possible to determine the transgression? - A difference will arise in the case of two pieces, one heleb and the other permitted fat, and a gentile first ate one piece and then an Israelite the other. According to Raba [he is exempt, for] there were not two pieces at the time when the Israelite ate his. According to R'Zera, too, [he is exempt, for] it is not possible to determine the transgression.