He was 40 years old when he enlisted in 1861 (3).
On 21 July 1846, he (probably) married Sarah Faunce in the First Presbyterian Church of Kensington, Philadelphia County, Pennsylvania (4). (I say "probably" because I'm not completely confident that this is the right James Fritzinger.)
He enlisted and was mustered into service on 28 September 1861 (1, 3). He was enlisted for three years, at Philadelphia, Pennsylvania, by Captain Dye (3). He served as a private in company A (1).
He deserted on 31 October 1861 (1) or on 29 September 1861 (2) or between 2 August 1861 and 31 October 1861 (3).
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) (James Fritzinger)
2 register of deserters in company A (James Fritzinger)
3 company A descriptive roll, entry 13 (James Fritzinger [crossed out])
4 'Family history', Rootsweb.com WorldConnect, updated 1 January 2006 (searched 2 January 2006) (James S Fritzinger)
[I did not find him in the <www.ancestry.com> index to the 1890 veterans' census]
[I did not find him in the index on <www.ancestry.com> to the pension index by name (searched April 2006)]