Finishing one chapter and starting the next. Wrapping up some possible cases - for the relationships where the husband isn't present or available to continue with sotah proceedings, but his warning to her negates her claim on her ketubah even though she doesn't drink the bitter waters. Also, a mishnah that lists many of the halakhot that were taught in the Beit Midrash when R. Elazar ben Azariah took over the leadership, when Rabban Gamliel was deposed. The laws are far-ranging, though beginning with Sotah, and reporting the prowess of R. Akiva, in solving some issues that R. Yochanan ben Zakkai (who was no longer alive) predicted would be resolved by subsequent generations.