What is the ritual of the scapegoat and how is Tessie a scapegoat?

The ritual of the scapegoat is taken from the Old
Testament. Each year on the Day of Atonement, the Hebrews would choose 2 goats: one to
be sacrificed to the Lord and one to atone for the people's sins. The high priest would
lay his hands on the second goat's head and confess all the sins of the people, in
essence transferring their sin onto the goat. Then that goat would be led away from the
town and left to wander in the wilderness, taking the people's sins with it. See
Leviticus 16:7-10.

Note that unlike Jackson's story, the
ancient scapegoat was not killed. Many biblical scholars see Christ's death on the cross
as a type of scapegoat, in that he took the sins of humanity upon himself when he died,
making redemption available to all. It is that type of scapegoat that is portrayed in
this story: one person must die for the good of the community.