On today’s daf the Gemara discusses whether a specific place located in a public domain retains the status of that domain if it is not commonly used by people in that place. The three possible exceptions discussed by the Gemara are a brick, thorns and shrubs (hizmei ve-higi) and excrement.
The Gemara cites the halakha that Rabbah bar Sheila said that Rav Ḥisda said: If an upright brick was placed in the public domain and one threw an object from a distance of four cubits and he stuck the object to its side, he is liable for throwing in the public domain. But if the object landed atop the brick, he is not liable. Because the multitudes do not step on the brick, it is not a full-fledged public domain.
It was Abayye and Rava, who both said: And that is specifically when that brick is at least three handbreadths high, as then the multitudes do not step on it, and, therefore, even though the brick is standing in the public domain, it is considered an independent domain. However, thorns and shrubs, (hizmei ve-higi) even though they are not three handbreadths high, are not considered part of the public domain. Since people do not walk on thorns, those areas cannot be considered part of the public domain. And Ḥiyya bar Rav said: Even the place where there are thorns and shrubs in the public domain, if they were low, the place is considered part of the public domain. However, a place in the public domain where there are feces is not considered part of the public domain, as people do not walk there. And Rav Ashi said: Even a place in the public domain where there are feces is considered part of the public domain, since ultimately people who are rushing to work do not take care to avoid it and will step on it.
Hizmei can be identified as the thorny bush Ononis antiquorum L. from the Papilionaceae family. It is a small thorny bush whose height is 25–70 cm and is commonly found in fields and riverbeds. The leaves of the plant are usually clover-shaped, and its side branches are thorny and tend to branch out.
Higi is the common shrub in the Papilionaceae family, Alhagi maurorum Medik, which is a thorny bush with smooth non-serrated leaves. It usually grows to a height of approximately 30 cm and can grow to a height of 1 m. It is commonly found in fields and salt marshes.