The Mishnayot on today’s daf continue with discussions of situations where a person is limited in performing an activity or building something on his own property if it may cause damage to his neighbor. The second Mishna teaches of two specific cases where an owner is required to restrict his own activities because of such concerns:
1. If someone’s neighbor has a dovecote at the edge of his property, his neighbor cannot place a ladder within four amot of the dovecote, lest a nemiya use the ladder to access the dovecote, and
2. If someone’s neighbor has a mazḥila – a leader-gutter arrangement for collecting water – he cannot build a wall within four amot of the mazḥila, which would limit the owner’s ability to access it by ladder and keep it clean.
A nemiya is a mongoose – herpestes ichunemon – a small carnivorous animal. A mongoose eats almost anything, but its main source of sustenance is small animals that it tracks and kills. When a mongoose gains access to a coop or dovecote it would not only kill birds to eat, but would kill many others, as well. Its slender, supple body allows it to climb easily and to jump long distances, making it dangerous to leave a ladder close to a dovecote when such animals are around.
With regard to the mazḥila, the question raised by the commentaries is why it is fair that the owner of the mazḥila can force his neighbor to leave an area of his own field unused to accommodate the needs of the mazḥila‘s owner. Tosafot say that we must be discussing a case where the owner of the mazḥila either purchased or received this concession and the Mishna is simply discussing the amount of space that the agreement guarantees. The Ramban suggests that we are discussing a case where two brothers received the field as an inheritance and divided it between them, so each must allow full usage of what the other received in the agreement.