Decisions of the Sages were usually reached in a meeting place where the most prominent Sages would gather; the halakha would be determined according to a majority vote. The Mishna on yesterday’s daf describes an unofficial gathering of Sages in the home of Ḥananya ben Ḥizkiya. In a departure from routine, the majority ruled in favor of Bet Shammai. Many reactions to this incident were noted, among them the expression: “And that day was as difficult for Israel as the day the Golden Calf was made.”
Apparently, the dispute between the parties was very intense, and Beit Shammai’s majority was an unexpected development. The arguments with regard to assessment of these decrees continued during the subsequent generations. Nevertheless, due to the intensity of the arguments, the Sages decided not to abrogate the decrees.
Although the Mishna offers no details about the 18 decrees that were decided on that day, the Gemara on today’s daf discusses a number of them. For example, it was decided that washing in ordinary water following ritual immersion would deem the individual ritually impure, since an incorrect impression developed where people thought that it was the shower that purified, rather than the immersion. This led to a second decree that anyone showering would be rendered ritually impure, since people would not distinguish between a person who was pure from the start and one who was just purified upon emerging from immersion.
Somewhat surprisingly, a Torah scroll was deemed to be impure. The Gemara explains this decree –
Rav Mesharshiya said: Since at first, ignorant priests would conceal teruma foods alongside the Torah scroll, and they said in explaining that method of storage: This is sacred and that is sacred, and it is appropriate that they be stored together. Since the Sages saw that they were coming to ruin, as the mice, which were attracted to the teruma foods would also gnaw at the Torah scrolls, the Sages decreed impurity upon it. Once they issued the decree of impurity on the Torah scroll, the priests no longer placed teruma near it.