the leech and his patient

Chillingworth seems to cross the line in this chapter from having human motives to suffering inhuman possession. Indeed, although the narrator proceeded no further than calling Chillingworth “evil” in motives and in deed, now Chillingworth's soul is attacked, and he is even compared to Satan, a thief of men's souls. Pearl perhaps senses this evil more than anyone, calling Chillingworth "the Black Man" and telling her mother that he already has captured Dimmesdale's soul.

The end of the chapter brings to light some of what previous foreshadowing promised. Earlier, Chillingworth told Hester that he would be able to know her partner by reading his heart. In the final scene, he is in fact able to read Dimmesdale's heart and know the secret Dimmesdale is hiding. Hawthorne, however, indicates that Chillingworth is surprised by what he discovers, implying that Chillingworth never fully suspected Dimmesdale of being Pearl's father.