According to the Mishna (28a), if a person’s vessel drops in the public thoroughfare and someone becomes injured by slipping on the water or through contact with the broken shards, the owner of the vessel is responsible for the damage that was done.
Discussing this case leads the Gemara on today’s daf to debate the question of mafkir nezakav – whether someone can divest himself of something that he owns that will cause damage by declaring it ownerless. On this point the Gemara presents a disagreement between Rabbi Yohanan and Rabbi Elazar, one of whom says that the owner will remain responsible and the other saying that he will not. The Gemara tries to identify Rabbi Elazar as the author of the statement ruling that the owner remains responsible, based on another statement on the subject that is brought in his name – that there are two things that do not belong to a person, yet the Torah treats them as if they remained in his possession. These two things are a bor (a hole or ditch) that is dug in a public domain and ḥametz (leavening) on the eve of the Passover holiday from noon onwards.
The case of bor is straightforward – no one individual owns the public, yet if a person digs a hole and creates an obstacle, he will be viewed as responsible for the hole and the damage that it causes. With regard to ḥametz, the Gemara in Massekhet Pesaḥim rules that beginning at noon on the day before Passover, all leavened products become forbidden – not only to eat, but also to derive any benefit from. Such a situation will render the ḥametz to be considered ownerless, since it effectively has no value. Nevertheless, the Torah will hold the original owner to be responsible for having ḥametz in his possession on Passover, which is forbidden.
The Talmud Yerushalmi points out that the argument between Rabbi Yohanan and Rabbi Elazar applies only to inanimate objects left as obstacles in the public domain. No one would say that if a person places a wild animal there and declares it ownerless that he would not be responsible.