Ohalos, Chapter 9, Mishnah 7. Throughout this chapter the Mishna has been examining a large beehive, a kaveres, standing in the doorway of a house, with part of it inside and part of it protruding outside, and asking how tumah travels when a kezayis of a meis is found in one place or another. Our Mishna now returns to a distinction that the chapter raised once before, in Mishnah 3: what happens when the beehive is no longer a working beehive at all, so that it is no longer considered a keli?
At first glance one might think that losing the status of a keli is a loss. In the laws of tumah it is actually a ma'alah, an advantage. A keli that spans a doorway conveys tumah, but it does not seal anything off. An ohel, a tent-like covering, does both jobs: it spreads tumah beneath itself, and it also serves as a mafsik, a barrier that cuts the tumah off so that it cannot continue upward or downward. So precisely when the beehive is not a keli, it can protect what lies above and below it.
What Counts as a Working Beehive
The Mishna opens by narrowing the scope of what preceded it: "bameh devarim amurim," with regard to which matters was all this taught? The rulings of the previous two mishnayos hold true only "bizman shehi keli mecholcheles," so long as the kaveres is still doing its job as a hive, meaning that it has its bee holes, the small apertures through which the bees enter and leave, and that its owner has packed straw into it.
"Aval hoysa pechusa ufekuka bekash": if, however, this kaveres had become damaged, and the damaged spot was merely stopped up with straw, it has ceased to serve as a hive and consequently forfeits its status as a keli. "O pechusa": alternatively, the bee holes may indeed have been there, but the owner did not simply place straw inside loosely; he sealed the hive up tight, leaving no genuine opening (tight, that is, by the standards of such things). The Mishna supplies its own definition: "eizo hi pechusa? she'ein lah tefach bemakom echad," a kaveres that lacks a tefach of open space at any single point.
Once that is the case, the beehive is automatically not a keli. Bear in mind why it ever had keli status: a container this size holds forty se'ah in liquid measure, and something that large is not treated as a keli. The one reason it was reckoned as a keli in the earlier mishnayos was that it was a live, functioning beehive. Take away that function, and there is nothing left to call it a keli.
The Halacha in Our Case
Our case is a kaveres set in the doorway with its mouth pointed in toward the house. The Mishna rules: "kezayis min hameis nosun tachtehah," should a kezayis of a meis be positioned below the kaveres, that is, below the section extending past the house, then "kenegdo ad hatehom tamei," whatever lies directly below it is tamei down to the very depths. "Al gabah," should the kezayis instead rest upon the kaveres, once more on the part outside the house, then "kenegdo ad harakia tamei," the entire column rising above it up to the heavens is tamei, since nothing there stops the tumah.
"Besochah o babayis, tochah vehabayis temeiyim": if the kezayis is inside the beehive itself, or inside the house, both the inside of the beehive and the house become tamei. The reason is the direction of the mouth. Since the opening faces inward, tumah in the beehive travels out through its mouth into the house, and tumah in the house travels in through that same mouth into the beehive.
What that tumah does not do is affect keilim resting on top of the beehive or lying beneath it, on the portion outside the house. Since the beehive is not a keli, it is an ohel, and an ohel cuts the tumah off, preventing it from rising above it or descending below it.
The Novelty Here, and a Word from the Bartenura
The chiddush of this Mishna surfaces through contrast. Previously, when the hive's opening pointed away from the house, the ruling was the same whether or not it still served as a hive: tumah in the house left the house tamei and nothing beyond it. Now, with the opening turned inward, tumah within the kaveres and tumah in the house merge into one. Simultaneously, though, its very lack of keli status protects any keilim situated outside the house, whether above the kaveres or under it, since in that respect it acts as an ohel that stops the tumah from passing through.
One further point from the Bartenura. Although our Mishna opens with "bameh devarim amurim, bizman shehi keli mecholcheles," implying that the presence of the bee holes is what matters, the Bartenura holds that this qualification is lav davka. The holes make a practical difference only where the mouth faces outward: there we learned that even though the opening is turned outside, because the beehive has these holes, and although they are filled with straw they are not truly sealed, tumah inside the beehive still passes through into the house. But in our case, where the mouth faces the inside of the house to begin with, it makes no difference whether the beehive has holes or not. Tumah inside it would reach the house in any event.