He was 27 years old when he was enrolled (2).
He was enrolled and mustered into service on 4 November 1861 (1, 2). He was enrolled at Philadelphia, Pennsylvania (2). He was mustered in as a private, at Philadelphia, Pennsylvania (2). He served as a private in company B (1).
He was not on the muster-out roll when the regiment mustered out (1, 2).
1 Bates, Samuel Penniman. History of Pennsylvania volunteers, 1861-5. Harrisburg: B. Singerly, state printer, 1869-71. 5 volumes. 'Ninety-first regiment', volume 3, pages 186-233. (In the roster) (Albert Gibson)
2 Civil War Veterans' Card File, available at the Pennsylvania State Archives, searched 28 June 2004 (Albert Gibson)
[I did not find an entry for him in the index on <www.ancestry.com> to the pension index by name (searched February 2007)]