As we learned on yesterday’s daf (=page), the rule that when permitted and forbidden items become mixed together, the forbidden items can become batel (=nullified) does not always apply. When items retain their unique, independent status, it becomes much more difficult to view them as becoming batel.
Another situation that may cause items to be viewed as unique and preclude nullification in the ordinary manner, is when the items are a davar she-be-minyan – when they are things that are counted and sold by number rather than by weight. The example given by the Gemara are ketzi’ot – dried figs – that were terumah – tithes – that were pressed together in a mold with other such figs, and we cannot tell which ones are the ketzi’ot of terumah. According to Rabbi Yehudah‘s interpretation of Rabbi Yehoshua‘s ruling, such figs will not become nullified, since the ketzi’ot are sold as individual loaves. If, however, the figs of terumah were included in a mold together with other figs, then they will become batel, since they are part of the mixture.
The way figs — and, indeed, other fruits, as well — were preserved in the time of the Mishnah and Talmud, was by means of drying them out. Dried figs were known as ketzi’ot. As is explained in our Gemara, after removing the stems and drying the figs in the sun, it was common practice to press them together into loaves inside of barrels or other round receptacles, and the round loaves were called deveilim. The round loaves of igulei develah were usually large enough that it was difficult for an individual to lift one on his own.
According to most of the commentaries, the case in our Gemara is one where a single round loaf of terumah figs was placed in the top of a receptacle where it remained as a single unit and did not get mixed with the rest of the figs. Since these loaves are sold by number, Rabbi Yehoshua rules that they cannot become batel and we must treat all of the igulei develah as possibly being terumah.