Ketubot, Chapter Eight, Mishnah Three
Our mishnah discusses what is to be done with money that a wife somehow receives, for instance through an inheritance, while she is married. The general rule is that the money is used to buy land and then the woman receives title to the land and the husband is entitled to the usufruct, that is the money that is earned through use of the land.
1) [If a married woman] came into the possession of money, land should be bought with the money and the husband is entitled to the usufruct.
2) [If she came into the possession of] produce that was detached from the ground, land should be bought and the husband is entitled to the usufruct.
3) [If it was] produce attached to the groundRabbi Meir says, the land is to be valued as to how much it is worth with the produce and how much without the produce, and with the difference land should be bought and the husband is entitled to the usufruct.
a) The Sages say: produce attached to the ground belongs to the husband and produced detached from it belongs to the wife; [with the proceeds from the latter] land should be bought and the husband is entitled to the usufruct.
Section one: Section one sets out the general rule about money a wife receives while married. Money cannot be divided up as easily into principle and interest as can land, even though today we are accustomed to such a division. Were the husband to use the money there would be no interest. Were he to merely hold onto the money, there would be no usufruct. Therefore, land is bought so that there is both usufruct and principle. Today, we might say that he could put the money into the bank and use the interest, in the same way that an endowment fund works.
Section two: Produce detached from the ground is basically equivalent to money, and therefore it is sold in order to buy land.
Section three: The mishnah now discusses a more complex case, where she inherited land with produce attached to the land. According to Rabbi Meir, the value of this produce is part of the principle, and therefore that principle must be used to buy land, from which he receives only the usufruct. The way that the value of the produce is evaluated is by estimating the value of the land without the produce and the value of the land with the produce. The difference between these two amounts is used to buy land, and then he receives the usufruct. For instance if the land was worth 1000 zuz without produce and then 1200 with produce, the land is sold in order to buy a piece of land worth 1200. From this land the husband receives the usufruct.
The Sages rule that the produce attached to the land belongs to the husband. This is considered usufruct, even though this produce was not grown while his wife owned the land. Since it is usufruct its value goes straight into his pocket. Only the already-harvested produce belongs to her and is used to buy land, from which he receives usufruct.