Physician.

Graduated A.B. (1771) from the College of Philadelphia, where he also completed his medical courses (1774). Went to Edinburgh to complete his medical studies (1774). Due to the indiscretions and the imprudent behavior of his youth, he fell out of his father’s good graces. In 1779, he was in Bordeaux in search of Franklin’s advice and a means of returning to America. He returned to Philadelphia, acquired a large medical practice, and became a founding member of the College of Physicians. Attended at the Bush Hill emergency hospital (1793). Lectured on midwifery and other subjects (1793-99).

Son of Franklin’s old friend Edward Duffield, a Philadelphia clock and watchmaker.