OPINIONS: Rav Papi says that "Situmta" is a valid form of acquisition. Rav Chaviva says that this means that "Situmta" achieves a binding Kinyan, and the Rabanan say that although it does not achieve a binding Kinyan, one who performs a Kinyan of "Situmta" and violates the agreement is subject to the curse of "Mi she'Para." The Gemara concludes that the Halachah follows the view of the Rabanan, but in a place where the custom is that this is a valid Kinyan, it indeed functions as a valid Kinyan.
What is "Situmta"?
(a) RASHI (DH Situmta) explains that a "Situmta" is a seal affixed to a container of wine as a sign that it was sold (i.e. reserved for the buyer even though it is still in the seller's warehouse). Although the placing of the seal on the barrel is not a normal Kinyan, in a place where the custom is to finalize the transaction with such an act, it is considered a Kinyan.
The RE'AH and RITVA question Rashi's explanation. How could Rav Chaviva say that this is considered a Kinyan even in a place where there is no custom to acquire in this manner?
RAV YOSEF SHALOM ELYASHIV shlit'a (quoted in He'oros b'Maseches Bava Metzia) suggests that Rashi understands that the actual act of inscribing the barrel is not what effects the Kinyan, according to Rav Chaviva. Rather, the inscribing causes the seller to designate these barrels to the buyer, and thus he is unable to sell them to anyone else. The fact that he is unable to sell them to anyone causes all others to forgo their hopes of buying them ("Mesi'ach Da'as"), and thus the Kinyan takes effect.
(b) The RITVA quotes a different understanding of the Gemara in the name of RABEINU PINCHAS, the brother of the Re'ah. He understands that "Situmta" is the name of an unstamped coin which the seller gives the buyer when they agree to make the transaction. The two opinions in the Gemara argue about the nature of this transaction. Rav Chaviva understands that the picking up of the coin is like an act of Kinyan Chalipin, wherein one of the parties picks up an item to effect the transaction, and thus he maintains that it is a valid Kinyan. The Rabanan understand that it serves merely as a symbolic monetary payment which indicates that the parties have agreed to enter a transaction. Accordingly, one who retracts is subject only to "Mi she'Para."
The root of the dispute seems to be whether or not an act of finalizing a deal can have the status of a Kinyan. The Re'ah and Ritva maintain that only Kinyanim authorized by the are valid. Rashi maintains that any accepted manner in which merchants finalize their transactions is considered a valid Kinyan. The RASHBA, and most other Rishonim, seem to side with Rashi and rule that a custom can establish a Kinyan.
A major issue among the Poskim is whether such a Kinyan has the status of a Kinyan d'Oraisa or Kinyan d'Rabanan. The NESIVOS HA'MISHPAT (cited by the PISCHEI TESHUVAH CM 201:1) maintains that the Kinyan is mid'Rabanan. The CHASAM SOFER (cited by the Pischei Teshuvah) says that the Kinyan is mid'Oraisa, based on the Torah's rule that any monetary condition between two people is binding (as long as it does not contradict Halachah). When merchants have such a custom, it is considered as though they make a condition with each other that when an act of "Situmta" is done, the ownership of the object is transferred. The Chasam Sofer proves this from the words of the RAMBAN who explicitly says that the Kinyan is mid'Oraisa. (Y. MONTROSE)
2) LENDING SEEDS TO THE SHARECROPPER
OPINIONS: The Mishnah says that a person may lend to his sharecropper measures of wheat, to be repaid in kind (Se'ah b'Se'ah), in order that he plant the field. The Gemara quotes a Beraisa that says that this is allowed only when the sharecropper has not begun to work on the field.
The Gemara explains that the Mishnah and Beraisa are not in disagreement. The Mishnah refers to a case in which the local custom is that the sharecropper is responsible for supplying the seeds. Even if the sharecropper starts plowing the field, the landowner can fire him if he fails to supply the seeds. When the sharecropper lets the landowner supply the seeds, the sharecropper essentially is telling the landowner that he (the sharecropper) will take less wheat from the harvest. This is not a loan but rather an arrangement that the sharecropper will take a smaller salary. The Beraisa, on the other hand, refers to a place where the custom is that the landowner supplies the seeds. Therefore, once the sharecropper starts to work on the field, his job has started and nothing else is expected of him (other than work). Therefore, the seeds he receives are considered a loan.
How exactly does the Gemara understand the Beraisa?
(a) RASHI (DH Mari Ar'a) explains that in a place where the custom is that the landowner supplies the seeds and the sharecropper works the field, the deal between the landowner and sharecropper is considered established. If the landowner decides that the sharecropper should be responsible for supplying the seeds but the landowner will lend them to him, this is not an inherent part of the deal and therefore is considered an external loan. Since a loan of Se'ah b'Se'ah generally is forbidden, it is forbidden in this case as well. However, if the sharecropper did not yet start to work the field, the Beraisa would agree that such a loan is permitted, since the sharecropper and landowner may stipulate how much produce the sharecropper will receive for his work before the work has begun.
(b) The TALMIDEI HA'RASHBA (quoted by the BEIS YOSEF, YD 162) explain that even if the landowner told the sharecropper to supply the seeds, in a place where the custom is that the landowner supplies the seeds the sharecropper cannot be fired once he starts working the land, even if he fails to supply the seeds. Accordingly, the actual loan of seeds must be done before the sharecropper starts to work, and it cannot be merely an agreement that the sharecropper will borrow seeds from the landowner. This limitation applies even when there is a previous agreement that the sharecropper will supply the seeds. The Beis Yosef explains that in any place where the custom is that a person is considered to have started a job by doing a certain action, that action makes all of the details of the general custom take effect despite the specific conditions made by the parties in this particular deal. Rashi disagrees and maintains that in monetary matters, one may stipulate any he wants; once the landowner has made a condition that the sharecropper must supply the seeds, this makes the deal similar to a deal which is done in a place where the custom is that the sharecropper supplies the seeds. (Y. MONTROSE)