Ohalot, Chapter Thirteen, Mishnah Five
Our mishnah deals with a window between two rooms that is a square handbreadth and therefore will allow impurity to travel between one room and the other. However, if there is placed in the window something that is not susceptible to impurity, it reduces the size of the window and blocks the impurity from traveling through. The mishnah lists some of the things that cause the window to be reduced in size. Tomorrow’s mishnah will list things that do not block the impurity.
The following [objects serve to] reduce [the area of a square] handbreadth:
1) [A portion] of less than an olive-size of flesh [of a corpse] reduces [the opening for uncleanness that is] caused by a quarter of a kav of bones [from a corpse];
2) [A portion] of less than a barley-corn size of bone reduces [the opening for uncleanness that is] caused by an olive-sized portion of flesh;
3) Less than an olive-sized portion of a corpse,
4) Less than an olive-sized portion of carrion,
5) Less than a lentil-sized portion of sheretz;
6) Less than an egg-sized portion of food;
7) Produce growing next to the window,
8) A cobweb having substance;
9) The carcass of a clean bird that he did not intend to eat,
10) And the carcass of an unclean bird that had been intended [for food] that had not been rendered susceptible [to uncleanness], or which had been rendered susceptible [to uncleanness] but had not been intended [for food].
Section one: In one room there is a quarter kav of bones, an amount which causes impurity in an ohel. There is a window that is a handbreadth square that would allow the impurity to travel to the adjacent room. However, in the window there is a piece of flesh of corpse that is less than the size of an olive. In this case, the window size is considered reduced and the impurity is confined to the room in which the bones are found. However, if the impurity came from an olive sized portion of flesh and there was less than an olive sized portion of flesh in the window, the flesh in the window would be reckoned together with the flesh in the room, and the impurity would travel to the next room. In other words, like substances (flesh) join together whereas unlike substances (flesh and bone) do not.
Section two: This is the opposite scenario. In the room there is an olive-sized portion of flesh, sufficient to cause impurity in an ohel. In the window there is a barley-corn size piece of bone, which is not sufficient to cause impurity. Again, the piece of bone in the window reduces its size and the impurity doesn’t go to the other room. However, in this case if there was a quarter kav of bones in the room and a small piece of bone in the window, the size of the window would not be reduced.
Section three: The less than olive-sized portion of flesh is mentioned here again because it is the opposite of the olive-sized portion of flesh which does not reduce the window, as we will learn in mishnah six.
Sections four-six: These substances do not transmit impurity. Furthermore, since they are of a different substance than bones or flesh, they reduce the size of the window no matter what is in the house: bones or flesh.
Section seven: The produce reduces the size of the window if it began to grow near the window and then spread into the window.
Section eight: For the cobweb to reduce the window it must have substance.
Section nine: The carcass of a clean bird that one did not intend to eat (even had it been slaughtered properly) does not cause impurity. Therefore, it reduces the size of the window.
Section ten: The opposite is true for the carcass of an unclean bird. It causes impurity only if one intended to eat the bird and it was rendered susceptible to impurity by coming into contact with water after it died. If he intended to eat it, or it wasn’t rendered susceptible to impurity, it is not susceptible to impurity and it does reduce the size of the window.