let the barrel itself serve as a barrier. It should not be susceptible to impurity in this case, as an earthenware vessel does not contract impurity if its exterior is exposed to impurity. Rather, one must say that its opening faces inward, and it is rendered impure because the impurity enters through its opening. And if you wish, say instead that actually its opening faces outward, and with what are we dealing here? We are dealing with a metal barrel, which does contract impurity through its exterior.

The Gemara raises another objection to the assumption that an item for which there is a use does not reduce the dimensions of a window, even if is not susceptible to impurity, from a baraita (Tosefta, Oholot 14:6): With regard to grass that one plucked and placed in a window or that grew on its own in windows; and scraps of fabric that do not measure three by three fingerbreadths; and a limb or flesh dangling from an animal or a beast; and a bird resting in the window; and a gentile sitting in the window; and a child born after eight months of pregnancy, who is not expected to survive, that is placed in the window; and salt; and an earthenware vessel; and a Torah scroll, all these reduce the dimensions of the window. Consequently, impurity passes through only if there remains an open space of a square handbreadth. But with regard to snow, hail, frost, ice, and water, all these do not reduce the dimensions of a window.

The Gemara proceeds to challenge Shmuel’s ruling from each of the cases of the baraita. The Gemara asks: But according to Shmuel, who says that an item that has a use is not considered part of the window and does not reduce the dimensions of the space, grass is fit for consumption by one’s animal, so it will not remain in the window. Yet the baraita states that grass reduces the dimensions of the window. The Gemara answers: This is referring to afrazta, which is poisonous grass that is unfit for an animal to consume.

The baraita teaches: Or grass that grew on its own also reduces the dimensions of the window. The Gemara asks: But since the grass damages the wall, the owner will remove it. Therefore, it should not serve as a barrier to impurity. Rabba says: This is referring to a wall of a ruin, whose structural integrity is insignificant, and therefore the owner will not trouble himself to remove the grass. Rav Pappa says: The baraita may even be referring to a wall in a settled house, and it is referring to a case where the grass comes from three handbreadths beyond the window. In other words, the grass does not grow on the window but takes root some distance away, and from there it reaches the window. The homeowner is not particular about this grass and will not uproot it.

The Gemara further asks: Why do scraps of fabric reduce the dimensions of the window? After all, they are fit for patching a tear in a garment. The Gemara answers: This is referring to thick scraps, which are unsuitable for patching. The Gemara challenges: Nevertheless, they are fit for a bloodletter to wipe up the blood at the point of incision. The Gemara answers: It is referring to sackcloth, which scratches the skin, and would not be used for that purpose.

The Gemara asks: If it is referring to sackcloth, why does the baraita state that it is not three by three fingerbreadths? It should have said that it is not four by four handbreadths. Rough woven material of the kind used for sacks rather than clothes is susceptible to impurity only if its area measures at least four by four handbreadths. The Gemara answers: It is not actual sackcloth; rather, it is like sackcloth, i.e., it is stiff, and will therefore not be used by a bloodletter, but is woven like regular clothing.

The baraita teaches: And a limb or flesh dangling from an animal or a beast reduces the dimensions of a window. The Gemara asks: According to the opinion of Shmuel, why should this be so? After all, the animal can arise and escape, and therefore it should not be considered as part of the window. The Gemara answers: This is referring to an animal that is tied in place.

The Gemara challenges: But the owner of the animal will take it and slaughter it. The Gemara answers: It is referring to an animal that is non-kosher and will not be slaughtered. The Gemara challenges: Even so, he will take it and sell it to a gentile. The Gemara responds: It is referring to a lean animal, which no one will buy. The Gemara continues: Even if the animal does not move, there is a use for the part that is dangling, since he can cut it off and throw it to the dogs. The Gemara answers: Since there is suffering to an animal if he cuts it off, he will not do that.

The baraita further teaches: And a bird resting in the window reduces its dimensions. The Gemara challenges: But it will fly away, and therefore it should not be considered as part of the window. The Gemara answers: This is referring to a bird that is tied in place. The Gemara further challenges: But the owner will take it and slaughter it. The Gemara answers: This is referring to a non-kosher bird, which he will not slaughter. The Gemara continues: Even if it is non-kosher he will take it and sell it to a gentile. The Gemara responds: It is referring to a kelanita, a type of bird that is so bony that no one would purchase it to consume it.

The Gemara asks: But even so, he can give it to a child to play with, so why does it reduce the dimensions of the window? The Gemara answers: It is referring to a bird that scratches. The Gemara challenges: But a kelanita does not scratch. The Gemara answers: The baraita is referring to a type of bird that is like a kelanita in that it is bony, but is inclined to scratch people.

The baraita further states: And a gentile sitting in the window reduces its dimensions. The Gemara asks: But the gentile will arise and leave, so why does he reduce the dimensions of the window? The Gemara answers: This is referring to someone who is tied in place. The Gemara continues: Another person will come and release him. The Gemara answers: This is referring to a leper, whom people are afraid to touch. The Gemara challenges: Another leper will come and release him. Rather, this is referring to a prisoner of the monarchy. Since he is confined as a punishment, others are afraid to release him.

The baraita teaches: And a child born after eight months of pregnancy who is placed in the window reduces its dimensions. The Gemara challenges: Perhaps his mother will come and remove him from there. The Gemara answers: This is referring to Shabbat, when it is prohibited to move this child, as it is taught in a baraita: A child born after eight months is like a stone with regard to the halakhot of set-aside [muktze], and therefore it is prohibited to move him; but his mother may bend over the child and nurse him, due to the danger that failure to nurse will cause her to fall ill.

The baraita teaches: Salt reduces the dimensions of a window. The Gemara challenges: It is fit for use and people will remove it from there. The Gemara answers: This is referring to bitter salt, which is not used as a seasoning. The Gemara challenges: Nevertheless, it is fit for tanning hides. The Gemara responds: It is referring to salt that has thorns mixed with it, and therefore it will not be used for tanning.

The Gemara challenges: Even so, since this salt is damaging to the wall, he will remove it from there. The Gemara answers: This is referring to a case where it sits on a shard of earthenware, and consequently it does not damage the wall. The Gemara states: If it is resting on earthenware, let the shard itself serve as a barrier against the spreading of the impurity. Why, then, is the salt mentioned?