And if one may not place an item that might cause damage close to his neighbor’s boundary, how can you find a case where each neighbor is damaging the property of the other? Rav Pappa says: This is referring to a buyer who purchased part of his neighbor’s field, and it contains a substance or items that might cause damage, e.g., the water in which flax is steeped or mustard. In the other section of the field the neighbor retained an item or substance that could be damaged. In this manner, it is possible for the item that causes damage to be found near the boundary of the neighbor without one having violated the ruling of the mishna.

The Gemara asks: If this is referring to a buyer, what is the reason of the Rabbis, who say that the neighbor can demand that the buyer distance that which causes damage? After all, he has not acted improperly. And furthermore, what is the reason of Rabbi Yosei for disagreeing only in the case of the mustard and the bees? Even the case of water in which flax is steeped and vegetables is also subject to the same reasoning: Why should he have to distance his water, considering that he did not act improperly?

Ravina said that the explanation is as follows: The Rabbis hold that the responsibility falls on the one who causes damage to distance himself. The one who has the potential to cause damage must act to prevent the damage from occurring. This is the halakha even if his initial placement was done in accordance with halakha, as in the case where one bought part of a field.

The Gemara asks: Does this prove by inference that Rabbi Yosei, who disagrees with the ruling of the Rabbis, holds that that the responsibility falls on the one whose property was damaged to distance himself; i.e., to avoid being damaged? But if the responsibility to distance oneself falls on the one whose property was damaged, even in the case of water in which flax is steeped and vegetables the owner should also not have to distance himself. Why does Rabbi Yosei distinguish between that situation and the case of bees and mustard?

Rather, actually Rabbi Yosei also holds that the responsibility to distance oneself falls on the one who causes damage, even if he did not act improperly. And this is what Rabbi Yosei is saying to the Rabbis: Your explanation works out well with regard to water in which flax is steeped and vegetables, where the one who causes damage must distance himself, as these damage those, but those do not damage these, i.e., the water in which flax is steeped damages the vegetables, but the vegetables do not damage the water. But in the case of mustard and bees, they both damage one another. In light of this factor, and since the initial planting of the mustard was permitted, the owner of the bees should distance them from the mustard.

And as for the Rabbis, how do they respond to this claim? They maintain that bees do not damage mustard. Their reasoning is that if it is referring to a seed, the bees will not find it. If it is referring to a leaf, it will grow back, and therefore no damage has been caused.

The Gemara asks: And does Rabbi Yosei hold that the responsibility falls on the one who causes damage to distance himself? But didn’t we learn in a mishna (25b) that Rabbi Yosei says: Even though the cistern preceded the tree, the owner need not cut down the tree, as this one digs a cistern in his property, and that one plants the tree in his property? Rather, actually Rabbi Yosei holds that the responsibility falls on the one whose property was damaged to distance himself. And Rabbi Yosei spoke to the Rabbis in accordance with their statement.

The Gemara elaborates: Rabbi Yosei was saying to the Rabbis: In my opinion, the responsibility falls on the one whose property was damaged to distance himself, and therefore even in the case of water in which flax is steeped and vegetables, the owner of the water need not distance himself. But according to your opinion, that the responsibility falls on the one who causes damage to distance himself, this works out well with regard to water in which flax is steeped and vegetables, as these damage those and those do not damage these. But mustard and bees both damage one another, and if the mustard owner acted properly, the owner of the bees should be required to move his bees.

The Gemara continues: And how do the Rabbis respond to this claim? They hold that bees do not damage mustard: If this is referring to a seed,