Question: Why are R. Eliezer stringent and R. Yehoshua lenient here (when black figs fell into white ones) but in the case of a Litra of Terumah figs pressed onto a jug, it is the opposite?

Answer (R. Yochanan): There are two opinions. (One understands that just as R. Eliezer is stringent when white figs fell into black figs, he's also stringent when the Litra of Terumah figs were pressed onto a jug. And the other understands that just as R. Yehoshua is stringent in the pressed Litra, he's also stringent when black figs fell into white figs.)

(Baraisa): R. Eliezer says that if it was known which color fell, it is not annulled, since only 50 can be used to annul it. And R. Yehoshua says - whether or not it is known, it is not annulled. This is R. Meir's version of their disagreement.

But R. Yehuda said that R. Eliezer says - whether or not it's known, it's not annulled; and R. Yehoshua says - whether or not it is known, it's annulled.

(R. Akiva): When it's known, it's not annulled; when it's not known, it's annulled.

If there was a Litra of dried Terumah figs pressed onto the mouth of a jug or a circular basket and it's not known where it was pressed...

(R. Meir): R. Eliezer says that only if there are 100 Litra it's annulled. R. Yehoshua says that if there are 100 mouths, it is annulled. If not, the (figs at the) mouths are prohibited and the figs underneath are permitted.

(R. Yehuda): R. Eliezer says that if there are 100 mouths, it is annulled; if not, the mouths are prohibited and underneath are permitted. R. Yehoshua says that even if there are 300 mouths, it is not annulled.

This understanding of R. Yehoshua shows that the mouth of a barrel is considered something that is normally counted (i.e. sold by number).

This supports R. Yochanan, who said that there are two opinions as to the disagreement between R. Eliezer and R. Yehoshua.

(In a Mishnah in Maseches Orlah 3:7, R. Meir and the Chachamim disagree. According to R. Meir, any prohibited items that are usually sold by count prohibit a mixture. The Chachamim applied this rule to only 6 items. The Amoraim later disagreed in understanding the opinion of R. Meir.) This supports the one that holds that all items that are sometimes sold by count prohibit (and aren't annulled).

This also teaches that if a gourd of Terumah becomes mixed with Chulin gourds - even one into 100 prohibits.

(Baraisa continues): If a person pressed a Litra of pressed Terumah figs onto the mouth of a jug or basket, but he does not know where (on the jug) he pressed it, all agree that it is annulled.

(R. Avin): Each jug (or basket) must have a little over two Litra in order that the Terumah figs can be annulled in the majority.

(Mishnah): If a Se'ah of Terumah fell onto a pile in a storage room (and became mixed with the top layer of produce) and a person skimmed off the top layer...

(R. Eliezer): If in the skimmed off produce there are 100 Se'ah (of Chulin aside from the Terumah), the Terumah is annulled.

(R. Yehoshua): It is not annulled. (Since by skimming off the top layer he's trying to annul the Terumah, it's not permitted). If a Se'ah of Terumah fell onto a pile in a storage room, he should remove any produce that might be Terumah (and the rest of the pile may be eaten as Chulin).

If so, when did they say that Terumah is annulled in 101 parts? When he doesn't know whether the top of the pile became mixed with the rest of it or into which pile the Terumah fell.

Two boxes or two storerooms, each of which contained 50 Se'ah, and he doesn't know into which box or storeroom the Terumah fell, they annul each other.

(R. Shimon): Even if they are in two different cities, they annul each other.

(R. Yosi): A case once came before R. Akiva of 50 bundles of vegetables into which fell a bundle of half Terumah and half Chulin. I told R. Akiva that it should be annulled, and he agreed. It's not because Terumah is annulled in 51 parts, but rather because there were 102 halves there.

(Gemara) Question: The opinion of R, Eliezer was switched - there he said that the lower ones annul the upper ones. Here he said that only if there are 100 Se'ah in the skimmed part is it annulled, but the Chulin at the bottom of the pile cannot annul?

Answer (R. Yirmiyah/ R. Chiya citing R. Yochanan/ Shimon bar Vava citing Kahana): They viewed the case of R. Eliezer (in our Mishnah) like an intentional case.

Answer #2 (R. Ila/ R. Asi citing R. Yochanan): They viewed his case like a Se'ah removed from 100 Se'ah.

According to R. Asi, it is permitted to intentionally skim off a thicker layer in order to increase the amount of Chulin. According to Kahana, it is prohibited.

If he skimmed and then again skimmed, according to R. Asi, it is permitted; according to Kahana, it is prohibited.

According to R. Asi, even if he transferred the entire pile, it is annulled. According to Kahana, he must leave some behind.