Commentary for Bava Metzia 3:7
הַמַּפְקִיד פֵּרוֹת אֵצֶל חֲבֵרוֹ, הֲרֵי זֶה יוֹצִיא לוֹ חֶסְרוֹנוֹת. לְחִטִּין וּלְאֹרֶז, תִּשְׁעָה חֲצָאֵי קַבִּין לְכוֹר, לִשְׂעֹרִין וּלְדֹחַן, תִּשְׁעָה קַבִּין לְכוֹר, לְכֻסְמִין וּלְזֶרַע פִּשְׁתָּן, שָׁלשׁ סְאִין לְכוֹר. הַכֹּל לְפִי הַמִּדָּה, הַכֹּל לְפִי הַזְּמָן. אָמַר רַבִּי יוֹחָנָן בֶּן נוּרִי, וְכִי מָה אִכְפַּת לָהֶן לָעַכְבָּרִין, וַהֲלֹא אוֹכְלוֹת בֵּין מֵהַרְבֵּה וּבֵין מִקִּמְעָא. אֶלָּא אֵינוֹ מוֹצִיא לוֹ חֶסְרוֹנוֹת אֶלָּא לְכוֹר אֶחָד בִּלְבָד. רַבִּי יְהוּדָה אוֹמֵר, אִם הָיְתָה מִדָּה מְרֻבָּה, אֵינוֹ מוֹצִיא לוֹ חֶסְרוֹנוֹת, מִפְּנֵי שֶׁמּוֹתִירוֹת:
If one deposited fruits with his neighbor [and the latter mixed them up with his fruits and ate of them without knowing how much, when he comes to return them,] he deducts for [the normal] loss: for wheat and rice, nine half-kavin to a kor. [The kor is thirty sa'ah; the sa'ah is six kavin.] For barley and millet, nine kavin to a kor. For spelt and flax seed, three sa'ah to a kor, all according to the amount [i.e., the same for each kor], all according to the time [that he left them with him. For each year he deducts that amount.] R. Yochanan b. Nuri said: What difference does it make to the mice? Do they not eat [the same amount] from a large measure as from a small one? [Therefore,] he deducts the loss only for one kor, [i.e., nine half-kavin for a year, whether for one kor or for ten.] R. Yehudah says: If it were a large amount [i.e., if he deposited with him a large amount, ten korim and above], he does not deduct for loss, for there is a surplus. [For in the time of threshing, when the grain is deposited, it is dry; and in the rainy season, when it is returned, it is swollen, so that too much is not lost because of the mice, the mice not eating that much from ten korim. Therefore, the swelling compensates for the eating of the mice. The halachah is neither in accordance with R. Yehudah nor with R. Yochanan b. Nuri. All of these measurements obtain in Eretz Yisrael and in the days of the tannaim. But in other lands and in these times, all is in accordance with the normal loss of seeds in those lands and times.]
Bartenura on Mishnah Bava Metzia
English Explanation of Mishnah Bava Metzia
All is in proportion to the quantity and according to the time [it is left]. Rabbi Yochanan ben Nuri said: “But what do the mice care about [the quantity]? Won’t they eat [the same amount] whether there is a lot or a little? Rather, he may exact a reduction from only one kor.
Rabbi Judah says: “If the quantity was great he may not exact any reduction, since the produce increases in bulk.”
Mishnayoth seven and eight deal with the reductions in the quantity of certain deposited products (produce, wine, olive oil etc.) that a guardian is permitted to make when he returns the products to their owner.
In our mishnah Reuven left his produce with Shimon and is now coming back to reclaim it. Shimon need not return exactly that amount that Reuven left but is legally permitted to reduce some of the quantity, on the assumption that mice would have eaten some of the produce. The mishnah then proceeds to list how much can be reduced for different types of produce.
According to the anonymous opinion in section two the amounts listed in section one can be reduced for each kor (a measure of volume) for each year that the produce was left with Reuven. Rabbi Yochanan ben Nuri raises a difficulty on this opinion. He points out that the mice will eat the same amount whether there is a lot or a little. In other words if there are 10 kor or 1 kor the mice will still eat only nine half kabs of wheat or rice. Therefore, according to Rabbi Yochanan ben Nuri no matter how many kabs of produce there are, Shimon may only reduce from one of them.
Rabbi Judah states that if the amount of produce was large than Shimon may not reduce at all. According to Rabbi Judah, large amounts are measured in heaping imprecise measurements. Therefore the extra that was heaped on top of a strict measurement is enough to compensate for the loss to the mice.