Terumot, Chapter Four, Mishnah Eleven
Our mishnah continues to deal with cases of terumah getting mixed in with hullin and again we see that Rabbi Joshua and Rabbi Eliezer disagree.
1) A seah of terumah which fell on top of a pile and he skimmed it off:
a) Rabbi Eliezer says: if in that which he skimmed off there are hundred seahs, it can be taken out [through a ratio of] one hundred to one.
2) But Rabbi Joshua says: it cannot be brought up.
3) A seah of terumah which fell on top of a pile, he must skim it off.
a) If so, why did they say that terumah can be taken up in one hundred and one parts?
b) [Only] if it is not known whether it has become mixed up or where it has fallen.
Section one: The case in our mishnah is one in which a seah of terumah fell on top of a pile of hullin and the terumah remained on top of the pile. Rabbi Eliezer holds that if in the top part of the pile there are one hundred seahs of hullin, then the one seah can be removed and the rest can be eaten. In other words, when trying to figure out if we have a 100-1 ratio, we can only take into consideration that which is on the top because, as we shall learn below, when terumah falls on top of a pile, one must skim it off. The bottom rows of produce cannot count toward the ratio.
Section two: Rabbi Joshua holds that since he must skim off the top, he cant also take out one seah, even if there is a 100-1 ratio.
Section three: This section explains the rule that stands behind the debate in the previous sections. When terumah falls into a pile of non-sacred produce (hullin) the first thing that one must do is attempt to skim it off the top. The rule that if there are 100 parts hullin to one part terumah one may take out any one part and give that to the priest and eat the rest only applies in two situations. 1) It is not known whether the terumah was mixed up or not; 2) the exact location of the terumah is unknown. However, if one knows that the terumah has not become mixed up and he knows where it is, he should just skim it off the top.