Terumot, Chapter Three, Mishnah Two
This mishnah is a direct continuation of the end of yesterdays mishnah. There we learned that if a person is not sure if the wine he gave as terumah was vinegar when he gave it, the first terumah counts and he must give terumah again. The end of the mishnah stated that each of these terumot on its own does not make non-sacred produce into medumma which is a mixture into which terumah has fallen. Our mishnah discusses what happens if both terumot fall into the same mixture.
1) If one of them falls into non-sacred produce, it does not make [the mixture] medumma [a mixture into which terumah has fallen].
a) If the second of them falls [then] into another place, it also does not make it medumma.
2) But if both fall into one place, they do make it medumma, according to the size of the smaller of the two.
Section one: If any one of these terumot falls into a batch of non-sacred produce, it does not render it medumma. This is because neither of these are certainly terumah and doubtful terumah does not cause non-sacred produce to become medumma. The non-sacred produce remains permitted to non-priests.
Section two: However, between the two of them, one is certainly terumah (as I explained at the end of yesterdays mishnah). Therefore, if both fall into non-sacred produce, they do render it medumma.
Before we understand the last clause of this section, we need to remind ourselves about the laws of medumma. If terumah falls into non-sacred produce, if there are less than 100 parts non-sacred stuff for every part terumah, then the whole mixture can only be eaten by a priest. A person would sell the mixture to a priest, reducing the price of the terumah that fell in, which he must give him for free.
However, if there are more than 100 parts non-sacred stuff for every part terumah, then the person may take out the measure of whatever terumah fell into the produce, and give the terumah to the priest and the rest goes back to being non-sacred produce. Here, the ratios are based on the smaller of the two terumot that fell into the other produce. So if one terumah is two pounds, and one terumah is 1 pound, if they fall into 100 pounds, he can simply take out the terumot and give them to the priest and keep the rest for himself.