(Mishnah): If a Se'ah of Terumah fell into 100 Se'ah of Chulin and he ground all of it and the Chulin was reduced; just as the Chulin became less, we say that the Terumah also became less and it is permitted.

If a Se'ah of Terumah fell into less than 100 Se'ah of Chulin and he ground it and the Chulin increased; just as the Chulin increased, so too the Terumah increased, and it remains prohibited. If it is known that the wheat of the Chulin is better than that of Terumah, it is permitted.

If a Se'ah of Terumah fell into less than 100 Se'ah of Chulin and then afterwards, more Chulin fell in, if it was inadvertent, it is permitted; if it was intentional, it is prohibited.

(Gemara): Not only is it if the Terumah was reduced, but even if the Chulin is poor quality and will not produce a large quantity when it is ground; and the Terumah is good quality and will produce a large quantity - he may still grind the mixture and it is permitted.

(Baraisa): The coarse bran of Terumah is not considered part of the Terumah to prohibit the Chulin (since it is not human food). But coarse bran of Chulin is considered part of the Chulin to annul the Terumah.

Question (R. Bayvai): Does the coarse bran of the Terumah combine with the Chulin to annul the Terumah?

Answer: Yes, from the statement of Rav Huna that if one cooks a prohibited egg in a pot of food, the shell combines with the egg to prohibit (if the prohibition gives taste).

An example of Rav Huna's teaching is when a Se'ah of Terumah fell into 100, that its Zunin and coarse bran are left there to combine and therefore prohibit. If it fell into less than 100, you remove the Zunin and coarse bran from the Terumah, thereby allowing the Chulin to become 100 times the Terumah.

Similarly, if a Log of clear Terumah wine fell into 100 Log of cloudy Chulin wine, you do not remove the sediment from it (but rather, the sediment combines with the rest of the Chulin to annul). If a Log of cloudy Terumah wine fell into less than 100 Log of clear Chulin wine; you remove the sediment from the Terumah wine, thereby allowing the Chulin to annul the Terumah.

(Baraisa): (The Mishnah taught that if it's known that the wheat of the Chulin is better than that of Terumah, it is permitted.) It's permitted to grind the wheat in order to annul the Terumah.

(The Mishnah in Maseches Orlah 1:6 teaches that if a vine shoot of Orlah or Kilayim (that was still connected to the ground) became mixed up with other shoots, he may not pick them in order to annul them. The Baraisa follows the opinion of R. Yosi (there who disagrees with the first opinion saying) that he may even pick them with intent to annul it.

(R. Zeira): It is the way of Kohanim to grind up prohibited Terumah mixtures in their homes.

Question: What's the difference between the two opinions?

Answer: Kilai HaKerem. (Grains of Kilai HaKerem became mixed with permitted grain. According to R. Yosi, he may grind and permit it; according to the Rabbanan, he may not.

(R. Abahu citing R. Yochanan): For all prohibited mixtures, if the permitted item is added until the prohibition is annulled - if it was done inadvertently, it is permitted; if done intentionally, it is prohibited.

Question: Isn't this written explicitly in our Mishnah?

Answer: The Mishnah was only speaking about Terumah (where the requirement of 101 parts is Rabbinic), but perhaps for other prohibitions, it would not have been permitted if it was added inadvertently.

(R. Acha citing R. Yochanan): Just as it's a Mitzvah to give rebuke when it will be accepted; so too it's a Mitzvah not to give rebuke when it will not be accepted.

(R. Elazar): Just as one should not rule that a Tamei item is Tahor; so too one should not rule that a Tahor item is Tamei.

(R. Abba bar Yaakov citing R. Yochanan): If a case comes before you and you are unsure whether it is doubtfully Tamei Terumah that should be suspended (i.e. not eaten but also not burned) or if it is certain Tamei and must be burned; wherever possible, rule that it must be burned, as there is nothing more precious in the Torah than the sacrifices of cows and goats that are burned (as their blood is taken into the Heichal).

Rebuttal (R. Yosi): Can you learn to something where it is not the Mitzvah (burning Terumah if it is not required) from something where it is its Mitzvah (burning the cows and goats)?!