Bates has two Thomas Ryan's: one in company I, enlisted 27 November, and not on the muster-out roll, and another in company D, enlisted on 26 November, and deserted. I have tentatively assumed they are the same person.
He was 44 years old when he was enlisted (4, 5).
He was enlisted and mustered into service in company I on 27 November 1861 (1 [possibly 26 November]; 4 [27 Nov]; 5 [co.D, 26 Nov]). He was enlisted at Philadelphia, Pennsylvania (4, 5). He was mustered in as a private, at Philadelphia, Pennsylvania (4, 5). He served as a private (1).
He was transfered to company D.
He deserted on 2 October 1861 [sic] (1) or 2 November 1862 (4).
He was declared a deserter on 27 February 1863 (2).
He was discharged at Camp Convalescent, on 13 February 1863 (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) (Thomas Ryan)
2 consolidated morning report, 91st PA, 27 February 1863 (Private Ryan)
3 company D, register of men discharged, entry 25 (Thomas Ryan)
4 Civil War Veterans' Card File, available at the Pennsylvania State Archives, searched 27 July 2004 (Thomas Ryan [co.I])
5 Civil War Veterans' Card File, available at the Pennsylvania State Archives, searched 27 July 2004 (Thomas Ryan [co.D]; rolls have 'Rayon, Thomas')