As we learned at the beginning of this perek (=chapter), many meal-offerings are divided, with part sacrificed on the altar and part given to the kohanim to eat. The Mishnah on today’s daf (=page) lists cases where the altar is “stronger” than the kohanim, inasmuch as it receives the entire meal offering, and cases where the kohanim are “stronger” than the altar, since they get to eat the entire offering, leaving none to be sacrificed.
Cases where the altar receives the entire offering are:
Minhat kohen – The meal-offering brought by a kohen, whether it was voluntary or obligatory
Minhat nesahim – The meal-offering that accompanied libations
The Gemara points out that it appears that there are other sacrifices, as well, where the entire offering remains on the altar with none given to the kohanim. In each example brought, however, the Gemara argues that the altar does not receive everything. Thus, for example, regarding an olah – a burnt offering – the kohanim do receive the skin of the animal. Regarding libations, which are poured on the altar and the kohanim receive nothing, the Gemara explains that they are not actually poured on the altar, rather they are poured into the shittin under the altar.
The shittin were pipes and hollow spaces in and beneath the altar. They opened as two small holes on the south-west corner of the altar and the blood and wine libations would run from them to the water tunnel under the Temple Mount and from there to the Kidron Valley. According to a tradition of the Ge’onim, the shittin were a cubit in width and 600 cubits in depth. Based on this tradition, when the Gemara in Masechet Sukkah (49a) describes how once every 70 years young kohanim would descend and remove the solidified remnants of wine, it is clear that they did not descend to the very bottom of the pipe, rather they went as far down as they could or used special implements to clean the passageway.