(Ze'iri): Also regarding the Isur of Haktaras (burning on the Mizbe'ach) Chametz, Heter joins to Isur!

Question: This must be like R. Eliezer, who expounds "Kol (Se'or... Lo Saktiru)". If so, Heter should join to Isur also regarding Chametz during Pesach! (It says "Kol Machmetzes Lo Socheilu"!)

Answer: It does! Ze'iri said his law regarding Haktarah to show that he disagrees with Abaye:

(Abaye): Even less than a k'Zayis is considered Haktarah. (Therefore, there is no need to join to comprise a Shi'ur.)

Ze'iri must hold that one is liable only for a k'Zayis.

Rav Dimi recited the above teachings.

Question (Abaye - Mishnah): If a porridge of Terumah contained Chulin garlic and oil, and a Tvul Yom touched part of them (the oil and garlic), it all becomes Tamei. (A Tvul Yom is one who immersed from Tum'ah today. He remains slightly Tamei until nightfall; he is Metamei Terumah, but not Chulin.)

If a Chulin porridge contained Terumah garlic and oil, and a Tvul Yom touched part, he is Metamei only the part he touched.

Question: Why is he Metamei the part he touched? (Tosfos - mid'Oraisa, the Terumah is Batel, and the mixture is Chulin. Rashi - the part he touched is smaller than the volume of an egg, and it cannot become Tamei.)

Answer (Rabah bar bar Chanah, citing R. Yochanan): This is because a non-Kohen is lashed for eating a k'Zayis.

(Summation of Abaye's question): This shows that one is liable for a k'Zayis of the mixture, i.e. the Chulin joins to the Terumah!

Answer (Rav Dimi): No. A non-Kohen is lashed for eating a k'Zayis (of Terumah) bi'Chedei Achilas Pras (within the time to eat a half loaf (three or four eggs). The Rosh explains that there is a k'Zayis of Terumah in a half-loaf of the mixture. This enables one who eats the mixture at the normal pace to ingest a k'Zayis of Terumah within the time for a half-loaf.)

Question (Abaye): Does the Torah really obligate one for eating a k'Zayis (of Isur) bi'Chedei Achilas Pras?

Answer (Rav Dimi): Yes!

Question (Abaye): If so, why do Chachamim argue with R. Eliezer, and exempt one who eats Kutach (a sharp dip containing Chametz) on Pesach?

Answer (Rav Dimi): Kutach is different. Normally, one does not eat a k'Zayis (of Chametz) within the time to eat a half loaf:

If he eats it by itself, this is abnormal. (Rashi - therefore, he is exempt; Tosfos - he would be liable, but Chachamim did not discuss such a case.)

If he eats it as a dip, he will not eat a k'Zayis (of Chametz) bi'Chedei Achilas Pras!

Question (Abaye - Beraisa): There were two mortars containing ground spices, one of Terumah, and one of Chulin. There was a pot in front of each, one containing Terumah, and one containing Chulin. The spices in the mortars fell into the pots. (We do not know which fell into which.) Both pots are permitted (the Terumah to Kohanim, and the Chulin even to Zarim), because we say that the Terumah fell into the Terumah, and the Chulin into the Chulin.

If the Torah obligates one for eating a k'Zayis bi'Chedei Achilas Pras, why are we lenient? (If the Terumah fell into the Chulin, the mixture is forbidden mid'Oraisa to a Zar. We must be stringent according to a Safek mid'Oraisa!)

Counter-question (Rav Dimi): You hold that Heter joins with Isur, and one who eats a k'Zayis of the mixture is liable like one who ate a k'Zayis of Isur. The same question arises!

Answer to both questions (Rav Dimi): Terumah of spices is only mid'Rabanan. (We may be lenient about a Safek Isur mid'Rabanan).

Question (Abaye - Beraisa): There were two boxes, one of Terumah and one of Chulin. A Se'ah (measure of grain) was in front of each, one of Terumah and one of Chulin. Each Se'ah fell into a different box; we do not know which fell into which. Both boxes are permitted (the Terumah to Kohanim, and the Chulin even to Zarim), because we say that the Terumah fell into the Terumah, and the Chulin into the Chulin.

If the Torah obligates one for eating a k'Zayis bi'Chedei Achilas Pras, why are we lenient?