What aspect of the slace trade does chapter 12 focus on?

The main purpose of this chapter is to present the reader with the various horrors of slavery, and Stowe pays particular attention to the plight of the mother whose child is ripped from her. The episode in which Haley takes a baby from its mother, and then she jumps in despair into the river, is a direct parallel to Eliza's situation. In this case, Stowe is presenting us with the grimmer outcome of the story of the desperate mother. Thus, she is reminding the reader that although Eliza escaped across the river, many more slaves were not so fortunate.