Bates (1) has Burgin; (2), (3), and (5) have Bergin; (4) has Burgen.
He was 18 years old when he enlisted (3, 7, 9 [50 in ?1892]). He was born in Philadelphia, Pennsylvania (3, 7, 9).
He was a baker (3, 7). He was living in Philadelphia when he was enrolled (7).
He was 5 feet 6-1/2 inches tall, had a light complexion, brown eyes, and red hair (3, 7).
He enlisted and was mustered into service as a private in company E on 20 August 1861, at Philadelphia, Pennsylvania (1, 3, 7). He was enlisted by Captain Lentz, for three years (3). He was mustered into service by Colonel Reiff (3).
He deserted in May 1863, after the Battle of Chancellorsville, and joined the Invalid Corps (3). He was returned to the regiment in September 1864 (4). The War Department ordered him returned and tried for desertion (3). He was charged with desertion, and tried before a general court martial on 17 September 1864, at the 2nd Brigade 1st Division 5th Corps (Col A L Pearson, 155th PA, President) (6). He was found not guilty of desertion but guilty of absence without leave, and sentenced (3, 4, 6):
to forfeit all pay and allowances due him to 21 September 1864
to serve three months after the expiration of his original term
However, this was not to affect his bounty (4).
He mustered out on 25 November 1864, at Pegrem House, Virginia, when his term expired (1, 3, 4, 5, 7, 8). He had served for thirty-nine months (9).
According to the pension index by regiment, he also served in company D of the 14th Veterans' Reserve Corps (11).
On 6 October 1892, he applied succesfully from Illinois for a pension (10, 11).
On 26 December 1892, he was admitted to the National Soldiers' Home (9). He was admitted from Wisconsin (9). He had rheumatism (9). He was apparently not receiving a pension (9).
On 17 June 1893, he was discharged from the Northwest Branch of the National Soldiers' Home (9).
He again applied for a pension on 15 February 1907 (11).
He died on 16 November 1912, at the Soldiers' Home, in [Erie], Pennsylvania (11).
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)
2 General Order no 56, Head Quarters, 1st Division 5th Corps, 18 October 1864, Michael Bergin
3 descriptive roll, company E, entry 17 (Micheal [sic] J Bergin)
4 register of deserters, company E, entry 14
5 company E, register of men discharged, number 31 (Micheal [sic] J Bergin)
6 general order 56, headquarters, 1st division, 5th corps, 18 October 1864
7 Civil War Veterans' Card File, available at the Pennsylvania State Archives, searched 17 May 2004 (Michael J Burgin; rolls have 'Burgen')
8 consolidated morning report, 91st Pennsylvania, 26 November 1864 (Privt Bergin [?])
9 Report of the Board of Managers of the National Home for Disabled Volunteer Soldiers for the fiscal year ended June 30, 1893. Serial Set volume 3151, session volume 1, 53rd Congress, 1st Session. House Miscellaneous Document 35. Page 717. (Mich'l Bergen)
10 pension index, by name (Michael J [?] Bergen)
11 pension index, by regiment, 91st PA Infantry, company E (Michael J Bergen)
[I did not find an entry for him in the index on <www.ancestry.com> to the 1890 veterans' census (searched April 2007)]