In Chapter X, Roger Chillingworth, the physician for the Reverend Dimmesdale, investigates the heart of the minister, digging into his heart, Hawthorne writes,
like a miner searching for gold; or rather, like a sexton delving into a grave....
But, much like many men of science, Chillingworth goes too far as he would see into the soul of his patient as well. Suspecting that the Reverend Dimmesdale has "a strong animal nature," Chillingworth probes deeper and deeper into Dimmesdale's spirit. He tells the minister that he has found some unsightly plants growing on a grave, where they grew out of his heart because he may have had "some hideous secret that was buried with him."
Dimmesdale remarks that perhaps the man wished to reveal this secret, but he could not. When Chillingworth asks why not, the minister replies that only Divine mercy can disclose secrets buried in the human heart since there is no retribution for sin, and it can only be revealed on "that last day." To this remark, Chillingworth asks why the person cannot "reveal it here?" Dimmesdale replies that some must keep their secrets in order to be able to continue the good they do. But, Chillingworth contends that such men deceive themselves. "Is Hester Prynne the less miserable, think you, for that scarlet letter on her breast?" Dimmesdale agrees,
I do verily believe it....Nevertheless, I cannot answer for her. There was a look of pain in her face which I would gladly have been spared the sight of. But still, methinks, it must needs be better for the sufferer to be free to show his pain, as this poor woman Hester is, than to cover it up in his heart.
As Roger Chillingworth tells Dimmesdale that he suspects that physical illiness can be a mainifestation of spiritual illiness, the conversation greatly disturbs Dimmesdale, and he hurries from the room. After he leaves, Chillingworth congratulates himself for having "made this step" of asking Dimmesdale about what lies in his heart. For, he has noticed the passion that possesses the minister, and if the minister can display such passion, he easily could have displayed another passion, an erotic passion:
"He hath done a wild thing ere now, this pious Master Dimmesdale, in the hot passion of his heart."
Now, Chillingworth is convinced that Dimmesdale has committed a sin of passion. He thinks he has found the man who sinned with Hester.