It was George Parkman's protruding jaw that did in John Webster. The jaw, plus an unusual set of false teeth made specially to fit it.
Both men were faculty members at Harvard Medical College. Both socialized in the rarefied world of Boston's elite. But George Parkman, medical doctor, was a true "Boston Brahmin" with inherited money to fund his lifestyle. John Webster, chemist and mineralogist, lived from paycheck to paycheck. As a college professor, he didn't have the needed funds to keep up the pretense.