Shevi'is, Chapter 10, Mishnah 7. The previous Mishnah dealt with the principle that a prozbul is written only if the borrower owns land - some parcel of real estate. Our Mishnah comes to discuss the status of a beehive: is it considered land, or is it in the category of movable property? Since the underlying question is whether it has the status of land or not, the Mishnah takes up all the halachos that depend on this definition, and in every one of them the Tannaim disagree as to whether the beehive is like land or not.
The opinion of Rabbi Eliezer - "it is like land":
The Mishnah opens: "Kaveres devorim, Rabbi Eliezer omer: harei hi k'karka" - a beehive, Rabbi Eliezer says it is like land. This is not merely an introduction to the halachos that follow, but a ruling in its own right, from which four halachos are derived:
"Harei hi k'karka" - it is like land. Land is acquired through three modes of acquisition: with money (handing over payment), with a document (handing over a deed), and with chazakah (performing an act upon the land itself). Since a beehive has the status of land, it too is acquired with money, with a document, and with chazakah. This is in contrast to movable property, which is acquired through meshichah - the buyer draws the object itself toward himself. Meshichah is not possible with land, and therefore land and everything attached to it do not require meshichah, but are acquired with money, with a document, and with chazakah.
"V'kosvin aleha prozbul" - and a prozbul may be written on its basis. The beehive is considered land, and therefore a prozbul can be written on the strength of the borrower's owning a beehive, just as though he owned land.
"V'einah mekabeles tumah bimkomah" - and it does not become susceptible to tumah while in its place. Since its status is that of land, it does not become susceptible to tumah as long as it is in its place, resting on the ground. But if it was picked up and moved from its place, and it is treated as a movable object, the status of a vessel returns to it and it becomes susceptible to tumah.
"V'harodeh mimenah b'Shabbos chayav" - and one who extracts from it on Shabbos is liable. This is the most surprising of the four: one who removes honey from the hive on Shabbos is liable to bring a chatas. This is regarded as detaching something attached to the ground, which carries liability on Shabbos, and the same law applies to a beehive.
The opinion of the Chachamim:
"Ein harei hi k'karka" - it is not like land. The beehive is not considered land, and therefore it is not acquired with a document or with chazakah, even if a document was written stating that he is selling him the hive.
"V'ein kosvin aleha prozbul" - and a prozbul may not be written on its basis. A prozbul is not written on the strength of the borrower's owning a beehive.
"U'mekabeles tumah bimkomah" - and it does become susceptible to tumah in its place. It carries the status of a vessel, and therefore it becomes susceptible to tumah even when it is resting on the ground in its place.
"V'harodeh mimenah b'Shabbos patur" - and one who extracts from it on Shabbos is exempt. One who takes honey from the hive on Shabbos is exempt, since the hive is not considered attached to the ground, and he is not detaching anything from the ground.
In summary: in this Mishnah, Rabbi Eliezer and the Chachamim disagree over one fundamental question - whether a beehive has the status of land or of movable property - and from it four halachos are derived: the ways in which it is acquired (money, document and chazakah as opposed to meshichah), writing a prozbul on the strength of owning it, becoming susceptible to tumah in its place, and liability or exemption for one who extracts honey from it on Shabbos.