 Money lending and real estate augmented his income; he also sold the land for the new Harvard Medical School and the Charles Street Jail.In 1837 he revisited Pitié-Salpêtrière Hospital, and he sent a letter and some sketches to the "Boston Medical and Surgical Journal", describing some Parisian hospitals.Parkman was a well-known figure in the streets of Boston, which he walked daily, collecting his rents (a thrifty man, he did not own a horse).