Four years before Ralph M. Waters implemented his formal anesthesia residency program at the University of Wisconsin, a young female doctor decided to study anesthesia under Louis G. Harding at the University of Iowa.

Mary Ada Ross was the daughter of a farmer outside Rockwell City, Iowa. She taught in a country school for four years before enrolling in the University of Iowa, where she earned her bachelor’s degree in 1920 and her MD in 1922. She then immediately entered training under Harding, the “Resident Physician in the Department of Anesthesia of the University Hospitals.” (This title was a misnomer, as University Hospitals didn’t have a formal Department of Anesthesia until 1963. Nevertheless, Harding was the first physician hired by the hospital specifically to administer anesthesia.)

Ross received her Certificate of Residency Training in Anesthesia in June 1923. According to the 2014 book The Wondrous Story of Anesthesia, her training is considered to be the first formal anesthesia residency in the U.S.

Ross remained at the University of Iowa as an assistant and associate of Harding for several years. She went on to work at hospitals in Chicago, Philadelphia, and Tulsa, OK, but spent most of her career at Good Samaritan Hospital in Los Angeles.