The second aliyah discusses blemishes of a Kohen that cause him to be disqualified for priestly duties. It then discusses ways in which a Kohen can become "tamai" (ritually impure, and how he can be restored to the state of "tahara" (purity) by immersing in a mikvah. The current Jewish quarter of the Old City of Jerusalem is where the Kohanim lived at the time of the Temple (may it be speedily rebuilt in our days, Amen). In the ruins of the ancient residences that are there, one can see a mikvah in nearly every house because the Kohanim had to frequently toivel (immerse) themselves to be ready for service.
Even today, many people toivel daily in a mikvah, before prayers, because of the tremendous purity and holiness the mikvah gives to the neshamah (soul).
The aliyah then concludes with the laws of who in the Kohane's household may eat of the offerings belonging to the priest.
