How is Mercy’s childhood described in Chapter 19? How did Mercy come to meet Mr. Butler?

Chapter 19 describes the death of Mercy's father, a mechanic at a pickle factory who died of gangrene after an injury. Mercy came to meet Mr. Buckle after she and her mother had fallen to the slums and in their hunger, her mother had prostituted out the young girl; Mr. Butler took them in and cared for them.