Alabama has produced a number of distinguished physicians, nurses, and medical institutions. Three Alabama physicians have served as Surgeon General of the United States, and several Alabama natives have significantly influenced medical education and the practice of medicine. Among Alabama's notable physicians and medical researchers are William Crawford Gorgas, Peter Bryce, and Joseph Volker. Montgomery physician Luther Leonidas Hill Jr. is regarded as the first American physician to perform a successful surgical repair on a wounded heart. In the early twentieth century, the Medical Association of the State of Alabama served as the model for the reorganization of the American Medical Association and was described by the AMA president as "the best medical association in the world." The School of Medicine at UAB is recognized as one of the nation's leading medical schools and research institutions, and it plays an important role in the economy of Birmingham and the state.