Terumos, Chapter 3, Mishnah 5. Our mishnah deals with the question of how precise a person must be when he designates Terumah, when he declares what the Terumah is. As we have learned, separating Terumah involves two distinct components: the designation - the verbal declaration that assigns a particular item as Terumah, and the physical separation - actually taking the Terumah and ultimately giving it to a kohen. The essential component is the designation: from the moment a person declares and identifies something as Terumah, the remaining portion becomes chullin, its status of tevel falls away, and it no longer contains Terumah mixed within it.
Since Terumah and chullin are opposites - it is either one or the other - the question arises: how precisely must a person identify which portion of the entire mixture of tevel is the Terumah, in order for the designation to be effective? On this the Tannaim disagree.
The view of Rabbi Shimon:
"Ha'omer terumas hakri zeh besocho, ma'asrosav besocho, terumas ma'aser zeh besocho - Rabbi Shimon omer: kara shem" - one who says that the Terumah of this pile of grain is inside it, in its inner part as opposed to its outer part, and likewise one who says this about the tithes or about the terumas ma'aser - in Rabbi Shimon's view this suffices for the designation to take effect and for the Terumah to be located.
Let us explain this. By saying that the Terumah is inside the pile, the person has established that the outer layer is certainly not Terumah, but he has still not identified which particular component or portion within the pile is the Terumah. There remains, then, a lack of certainty as to which kernels will be Terumah and which will not, but a certain measure of certainty has been achieved: the outer layer is from now on identified as chullin. In other words, the person has narrowed the uncertainty and has to some degree located the Terumah. In Rabbi Shimon's view this is enough for it to be an effective designation, so that, for example, it is no longer possible to take Terumah from the outer layer of the pile - what is done is done. The same applies to the tithes and to terumas ma'aser.
The view of the Sages:
The Sages disagree and hold that identifying the place where the Terumah is not located is not enough; one must state where it actually is. In their view, "ad sheyomar bitzfono o bidromo" - the declaration has no halachic significance and does not take effect unless the person identified a specific location: in the north of the pile or in its south, that is, in its northern half or its southern half. With this identification he fixes a specific place where the Terumah is located, and consequently also a place where it is not located - and that is sufficient.
It is worth noting an interesting discussion, which does not appear in this mishnah but elsewhere: how much of the northern portion is included in the statement "in its north," and where exactly the Terumah is located. This is a dispute among the Tannaim, and the halachah follows the Sages, that the intent is the upper quarter. That is, if we divide the pile into four quarters, the northernmost quarter is the quarter in which the Terumah is now located. The reason: had the person meant the entire northern half, he would not have said "the northern portion" but rather "on the northern side." It emerges that the Sages hold that one must be more precise in identifying a specific place where the Terumah is located, so that consequently there remains a place where it is not located, and the same applies to the tithes and to terumas ma'aser.
The view of Rabbi Elazar Chisma:
Rabbi Elazar Chisma takes the opposite extreme: "Ha'omer terumas hakri mimenu alav" - one who says that the Terumah of this pile shall be taken from it, from this very pile, has not identified any portion at all as distinguishing between chullin and Terumah; he has merely established that the Terumah will be located somewhere within this particular pile. Even so, this designation is enough to constitute a halachically valid declaration, and from now on the Terumah is located within this pile.
And if the student wonders: was the Terumah not already in the pile, so what has changed? Let us illustrate. Suppose a person has two piles before him, each containing fifty cups of grain. Before the designation, he had the option of taking one cup for the first pile and one cup for the second, or taking two cups from the first pile for both of them, or two cups from the second pile for both of them. After the designation, according to Rabbi Elazar Chisma, once he said that the Terumah of this pile is within it and comes from it, he can no longer take two cups from the second pile for the first pile, since he has established that the Terumah for this pile will come from it. It emerges that this is enough to be considered a designation.
The view of Rabbi Eliezer ben Yaakov:
Rabbi Eliezer ben Yaakov is also lenient like Rabbi Elazar Chisma, and he holds that as long as a person said that this is within that, that is sufficient. His disagreement centers on a different point: identifying the terumas maaser. At the beginning of the Mishnah we learned that the same rules apply equally to Terumah Gedolah, to maaser and to terumas maaser. On this Rabbi Eliezer ben Yaakov says that when separating terumas maaser, it must be separated specifically from the maaser. It is not enough to say that the terumas maaser is hidden somewhere inside the tevel and that it needs to be extracted and identified in a particular place; rather, one must first separate maaser, and once the produce is definitely maaser, then from that very maaser, and only from it and not from the tevel, may a person declare that the terumas maaser will come from it. And on this very point he agrees with Rabbi Elazar Chisma, that it is enough to say that the terumas maaser of this maaser is located somewhere within it; it is only that this does not take effect until he separates the maaser before taking the terumas maaser.
The halachah: In all of these cases the halachah was decided like the Sages: one may separate Terumah Gedolah, maaser and terumas maaser - all of them from the tevel, whether this one or that one or the other - and for the separation to take effect it is enough to designate a particular place where they are located, such as one who says on its northern side or on its southern side.