We then learn about the sale of liquids like wine or oil through a new Mishna. The agreed upon price of a liquid for sale can fluctuate up until the liquid has been measured out. After that point, the liquid has been acquired by the buyer. If a middle person was doing the selling and an accident occurred, like a barrel breaking, he suffers the loss. When a bottle is emptied, it is poured until the liquid stops flowing or until three drops come out. After this point, the drops that accumulate when the bottle is tilted belong to the buyer. The rabbis believe that a grocer need not wait for those three drops, but Rabbi Yehuda asserts that this is true just before Shabbat.
The Gemara discusses the job of a middle person, the ownership of the measure, and the status of those last drops if the bottle has been declared teruma. In its discussion of why the grocer need not wait for the three drops just before Shabbat, Rabbi Yehuda clarifies that this is done to accommodate the needs of the grocer who is extremely busy at that time.
We learn in a second new Mishna that if a person sends his minor son with a coin worth two issarim to a grocer and that grocer gives him an issar worth of oil and an issar in change and the child broke the vessel and lost the issar, the grocer is liable. Rabbi Yehuda exempts him because he did what the father had instructed. The rabbis agree that if the child held the vessel and the grocer measured into it, the grocer is exempt.
The Gemara wonders whether the grocer was told to send the oil and the tsar with an adult. But is that the case? And aren't children known to break things? Perhaps the child was sent with a flask because his father sold flasks and this trip was intended as a sales pitch. Wouldn't it make the grocer liable if he was the one to pick up the vessel and break it? Or perhaps the vessel was sold by the grocer. The rabbis agree that if the child held the vessel while the grocer poured the oil, the grocer is exempt.