Congress established the Medical Service of the
Continental Army on July 27, 1775, and placed a "chief physician & director general" of the Continental Army as its head. The first five surgeons general of the U.S. Army served under this title. An
Act of Congress of May 28, 1789, established a "physician general" of the U.S. Army. Only two physicians, doctors Richard Allison and James Craik, served under this nomenclature. A congressional act of March 3, 1813, cited the "physician & surgeon general" of the U.S. Army. That nomenclature remained in place until the Medical Department was established by the Reorganization Act of April 14, 1818. Additionally, physicians assigned to the U.S. Army were not accorded military rank until 1847. ==Surgeons general of the U.S. Army and their precursors==