- A person who creates an obstacle in a public place, and
- Two people who cause injury to one another.
The first issue is connected with the idea of a bor – a hole dug in the public thoroughfare – that causes damage. It leads to clarification of the level of responsibility that a person has when he creates such an obstacle, whether all such cases will be considered a bor and whether someone who suffered an accident will be held responsible for damage that it causes to others.
The first Mishna in the perek discusses a case where a person places a kad (a type of vessel) in the public thoroughfare. According to the Mishna, if someone trips on it and breaks it he will not be held liable for the damage, but if he was injured then the owner of the vessel (now referred to as a havit) will be responsible.
Aside from the legal issues that appear in this Mishna, the Gemara is disturbed by the terminology that is used, specifically, why did the Mishna open discussing a case of a kad and conclude by talking about the owner of a havit? Rav Pappa concludes that a kad and a havit are used interchangeably by the Mishna, as they mean the same thing.
Both a kad and a havit were large earthen vessels that were used to store liquids like wine and oil (although occasionally other things were stored in them). While our Mishna uses the words interchangeably, in places where distinctions were made a kad referred to a smaller vessel and a havit referred to a larger one.