תלמוד על בכורות 2:4

⁴⁶Mishnah Bekhorot 2:4. It is not totally clear what mortmain conditions for a shepherd are; cf. the extensive discussion in S. Lieberman, תוספתא כפשוטה בבא קמא-בבא מציעא New York 1988, pp 217–219.
The Yerushalmi Baba Meṣi‘a 5:7, quoting Tosephta Bekhorot 5:1,14, explains: “What is a mortmain flock? If [the owner] had 100 sheep and said [to the shepherd]: these are stipulated to be worth 100 gold denars, their lambs, their milk, and their shearings are yours, if they die, you are responsible, and for each one you give me a tetradrachma at the end, it is forbidden.” It is forbidden to the shepherd to receive a flock under these conditions from a Jew since most owners will structure the contract so they will make money, which turns the final payment (which accompanies the return of the flock to the owner) into a money-making proposition which looks like interest since the shepherd pays for the use of the flock which he received on credit. It is forbidden to pay interest to Jews. The same kind of contract is permitted with Gentiles. There, we have stated: “If somebody receives [a flock] under mortmain conditions from a Gentile, the young are free, the young’s young are obligated.”⁴⁷The parallel text is in Baba Meṣi‘a 5:7 (fol. 10b). Rebbi Jeremiah asked: There you say, the young are for the first, and here you say, the young are for the second⁴⁸In the Mishnah in Bekhorot, lambs are exempt because they belong to the Gentile even though the entire flock is the shepherd’s responsibility whereas the Mishnah here states that mortmain lambs belong to the husband who also carries the same responsibility as the shepherd.! Rebbi Yosa said, there, because the property rights are with the first, the young belong to the first. But here, because the property rights are with the second, the young belong to the second⁴⁹The contract of the shepherd specifies that the flock must be returned intact at a specified time; the interest of the Gentile is there all the time. In the case of marriage, if the wife predeceases her husband, he inherits from her; his obligation to return the dowry is conditional..

Rebbi Jeremiah asked: There¹²⁰Mishnah 5, which forbids handing over calves to be raised unless the rancher is paid for his work. you say that a paid trustee who would be responsible for accidents is forbidden. But here¹²¹Mishnah 6, which allows such contracts for adult animals without restrictions. you say that a paid trustee who is responsible for accidents is permitted. Does it not happen that an unpaid trustee agrees to be like a borrower^81,An agent is not liable for accidents only if he strictly acts in the principal’s interest. If he is permitted to use the other’s money for his own trades, be becomes liable as a borrower while remaining an agent (Babli 94a).¹²²The quote from Halakhah 5 is slightly out of place here. Since the rancher is supposed to use the animal for his purposes, he cannot be under the rules of the unpaid trustee; he is a paid trustee. But this is really irrelevant for the question; the main point is that the transaction involves an element of risk which shields it from the laws of interest, Note 115.? Rebbi Jeremiah asked: There¹²³Mishnah Bekhorot 2:4, quoted in the Babli 70b. The offspring of a Gentile’s mortmain animals in the hands of a Jewish tenant farmer are not subject to the laws of the firstling since the mothers are considered the Gentile’s property. you say that mortmain belongs to the first, but here you say to the second¹²⁴In the Halakhah here, the offspring is defined as the tenant’s property.. Rebbi Yose said, there since the essence belongs to the first, the offspring are counted for the first¹²⁵Since the owner can repossess the mother if the tenant is in arrears with his payment, the Gentile retains a monetary interest in the mother. This is enough to free the offspring from the rules of firstlings.. But here the essence belongs to the second since the offspring belong to the second¹²⁶As explained in the Halakhah. For the majority opinion in Mishnah Bekhorot 2:4, the offspring’s offspring is subject to the rules of firstlings for the same reason..