Chillingworth arrives in Salem and no one knows who he really is except Hester, whom he swears to secrecy. He sets out to befriend Dimmesdale because he suspects that he is Pearl's father. Chillingworth is a physician, and Dimmesdale becomes his patient. The doctor does all he can to befriend Dimmesdale and treat him, and they have long conversations about the nature of sin, hidden sin, etc. In chapters 9 and 10, Hawthorne develops the relationship between these two men. In chapter 10, Dimmesdale falls asleep, and Chillingworth sneaks up on him and pushes aside his garment to look at the minister's chest. What he sees throws him into an evil ecstasy:
Had a man seen old Roger Chillingworth, at that moment of his ecstasy, he would have had no need to ask how Satan comports himself, when a precious human soul is lost to heaven, and won into his kingdom.
The reader never finds out what this is, but from this point on in the novel, Chillingworth is convinced that what he has seen is proof that Dimmesdale has been Hester's lover and the father of Pearl. The reader must infer that there must have been some sort of symbol on Dimmesdale's chest - perhaps a letter A was burned into his chest, or the hairs on his chest formed the letter A. Or, perhaps he was wearing something around his neck - a lock of Hester's hair, or a lock of Pearl's hair.
What do you think?