Question: Who was the Major Union General that was an American physician who went on to become Surgeon General during the American Civil War ?

text: List of American Civil War generals (Union)
Union generals -- B

The following lists show the names, substantive ranks, and brevet ranks (if applicable) of all general officers who served in the United States Army during the Civil War, in addition to a small selection of lower-ranked officers who received brevets as general officers; while some 1,600 officers received or were nominated for brevets as general officers in the course of the war (or immediately following it for service during the war), only a small selection is listed here; only those who were killed in action, served as department heads within the army, had revoked or incomplete appointments or became U.S. President are listed here. In addition to their names and ranks, there is a small set of notes after every entry listing Medal of Honor or Thanks of Congress citations, West Point graduation dates, important political or Army offices held, retirements or deaths during the war (whether in action or other means), notable relations, rejections or expiration of appointments, or unique facts pertaining to this article (i.e. youngest general, last surviving general, etc. ); for all other information on their lives and accomplishments, please refer to their individual entries. If available, ranks are followed by the to rank from dates (i.e. the date on which the commission is effective) rather than the date of appointment or confirmation, which were generally months if not years later; this is particularly true in the case of brevets, most of which were granted after the war between 1866 and 1869. Note on abbreviations:
Name Substantive Rank Brevet Rank Notes
Bailey , Joseph Brigadier general , USV ( November 10 , 1864 ) Major general , USV ( March 13 , 1865 ) Received the Thanks of Congress ( June 4 , 1864 )
Baird , Absalom Major , USA ( November 12 , 1861 ) Brigadier general , USV ( April 28 , 1862 ) Major general , USA ( March 13 , 1865 ) Major general , USV ( September 1 , 1864 ) USMA , 1849 MOH , Battle of Jonesborough ( September 1 , 1864 )
Baker , Edward Dickinson Major general , USV ( September 21 , 1861 )  KIA , Battle of Ball 's Bluff ( October 21 , 1861 ) Rejected appointment as brigadier general , USV ( May 17 , 1861 ) Promoted to major general , USV posthumously U.S . Congressman from Illinois ( 1845-1846 , 1849-1851 ) U.S . Senator from Oregon ( 1860-1861 )
Baker , Lafayette Curry Colonel , USV , DC Cavalry ( May 5 , 1863 )  Nominated brigadier general by President Andrew Johnson April 26 , 1865 , but never confirmed
Banks , Nathaniel Prentiss Major general , USV ( May 16 , 1861 )  Received the Thanks of Congress ( January 28 , 1864 ) U.S . Congressman from Massachusetts ( 1853-1857 , 1865-1873 , 1875-1879 , 1889-1891 ) Speaker of the House ( 1856-1857 ) Governor of Massachusetts ( 1858-1861 )
Barlow , Francis Channing Major general , USV ( May 25 , 1865 )
Barnard , John Gross Colonel , USA ( December 28 , 1865 ) Brigadier general , USV ( September 23 , 1861 ) Major general , USA ( March 13 , 1865 ) Major general , USV ( July 4 , 1864 ) USMA , 1833 Superintendent , USMA ( 1855-1856 )
Barnes , James Brigadier general , USV ( November 29 , 1862 ) Major general , USV ( March 13 , 1865 )
Barnes , Joseph K. , M.D Brigadier general , USA ( August 22 , 1864 ) Major general , USA ( March 13 , 1865 ) Surgeon General ( 1864-1882 ) Surgeon at the deathbeds of Presidents Abraham Lincoln and James Abram Garfield
Barnum , Henry Alanson Brigadier general , USV ( May 31 , 1865 ) Major general , USV ( March 13 , 1865 ) MOH , Battle of Lookout Mountain ( November 24 , 1863 )
Barry , William Farquhar Colonel , USA ( December 11 , 1865 ) Brigadier general , USV ( August 20 , 1861 ) Major general , USA ( March 13 , 1865 ) Major general , USV ( September 1 , 1864 ) USMA , 1838
Bartlett , Joseph Jackson Brigadier general , USV ( March 30 , 1863 ) Major general , USV ( August 1 , 1864 ) Original appointment as brigadier general , USV ( October 4 , 1862 ) expired March 4 , 1863 U.S. minister to Sweden and Norway ( 1867-1869 )
Bartlett , William Francis Brigadier general , USV ( June 20 , 1864 ) Major general , USV ( March 13 , 1865 )
Baxter , Henry Brigadier general , USV ( March 12 , 1863 ) Major general , USV ( April 1 , 1865 ) U.S. minister to Honduras ( 1869-1873 )
Bayard , George Dashiell Captain , USA ( August 20 , 1861 ) Brigadier general , USV ( April 28 , 1862 )  USMA , 1856 DOW , Battle of Fredericksburg ( w. December 13 , 1862 , d. December 14 , 1862 )
Beal , George Lafayette Brigadier general , USV ( November 30 , 1864 ) Major general , USV ( March 13 , 1865 )
Beatty , John Brigadier general , USV ( November 29 , 1862 )  U.S . Congressman from Ohio ( 1868-1873 )
Beatty , Samuel Brigadier general , USV ( November 29 , 1862 ) Major general , USV ( March 13 , 1863 )
Belknap , William Worth Brigadier general , USV ( July 30 , 1864 ) Major general , USV ( March 13 , 1865 ) Secretary of War ( 1869-1876 )
Benedict , Lewis Colonel , USV ( September 12 , 1862 ) Brigadier general , USV ( March 13 , 1865 ) KIA , Battle of Pleasant Hill ( April 9 , 1864 )