J. P. Allison was appointed Assistant Surgeon of the 29th Tennessee Infantry on August 23/25, 1862 at Missionary Ridge. His pay records show that he received pay on July 5, 1864. No further records beyond this day were recorded in his file.
As he is the only Assistant Surgeon listed in Lindsley's Military Annals of Tennessee, I would assume he remained with regiment till the end of the war.
A Short History of The 29th Tennessee
The 29th Tennessee was officialy organized September 30, 1861, at Henderson's Mills. The Field Officers were as follows: (Colonels) Samuel Powel, Horace Rice, William P. Bishop. (Lieutenant Colonels) Reuben Arnold, Horace Rice, John B. Johnson, William P. Bishop. (Majors) Horace Rice, John B. Johnson, A. Kyle Blevins, Samuel L. McKamy. (Captains) W. W. McClelland, Samuel L. McKamy, Co. "A" M. H. Hancock, William A. Bible, Alphonse Chable, Richard M. O'Neal, Co. "B" Robert F. Patterson, James W. Fulkerson, John B. Hodges, Co. "C" James G. Rose, William P. Bishop, Co. "D" Abraham Kyle Blevins, L. N. Kyle, Co. "E" John Q. Arnold, James B. Johnson, Co. "F" Jeorge P. Faw, Isaac E. Reeves, Co. "G" James H. Coulter (or Coulston), Thomas S. Rumbough, James W. Henshaw, Co. "H" William Fry, John H. Craig, J. K. Bushong, Co. "I" Samuel Powel, Jacob Hamelton, George A. Edmonds, Jerome N. Martin, Co. "K" (note: Their was no Co. "J"). Co. A was from Bradley county; B, from Polk county; C, from Claiborne county; D, from Hancock county; E, from Hawkins county; F, ('The Greeneville Guards') from Greene county; G, from Washington County; H, from Greene County; I, from Washington County; and K, from Hawkins County. During the formation of Company D, the men were surrounded by a large force of about five-hundred unionists. They were ordered to surrender or be killed. Men were chosen to send a message for help during the night, one day later, two-thousand Confederate troops converged on the town. The unionists dispersed. Most of the companies were the first to join the Confederacy from their counties, and thus were some of the best troops. Unfortunately anyone from East Tennessee was not trusted and they had to prove themselves in battle before they were accepted. Of the officers, Powel resigned in November of 1862; Rice was wounded and taken prisoner at Franklin on November 30, 1864; Arnold was not re-elected at the reorganization in 1862; Johnson died July 15, 1864; and Blevins was killed May 17, 1864. Some of the battles the 29th fought in include: Rock Castle, Mill Springs, The Corinth Campaign, Munfordville, Perryville, Murfreesboro, The Tullahoma Campaign, Chickamauga, Chattanooga (Federals did not push them back, they held their ground), The Atlanta Campaign, Resaca (along with the 12th, drove the yankees through the streets) New Hope Church, Kennesaw Mountain (in the dead angle with the 1st and 27th consolidated, decimated the union forces attacking, read Co. "Aytch" by Sam Watkins), Peach Tree Creek, Atlanta, Atlanta siege, Jonesboro, Franklin, Nashville, The Carolinas Campaign, and Bentonville (The regiment was sleeping near Gen. Johnston's headquarters, when a federal force attacked, the regiment instantly formed, and attacked with no less than Johnston, Hardee, and Wade Hampton, leading them. The small remains of the regiment saved Johnston's headquarters and pushed back the Federals. The 29th surrendered with the rest of the Army of Tennessee at Greensboro, on the 26th of April 1865.
29th Infantry Regiment was assembled at Henderson's Mills, Greene County, Tennessee, in September, 1861. Its members were raised in the counties of Bradley, Polk, Claiborne, Hancock, Hawkins, Greene, and Washington. The unit took part in the conflicts at Fishing Creek, Munfordville, and Perryville, then was placed in P.Smith's, Vaughan's, and Palmer's Brigade, Army of Tennessee. During September, 1864, it was consolidated with the 11th Regiment. It participated in the various campaigns of the army from Murfreesboro to Atlanta, was involved in Hood's winter operations in Tennessee, and fought in North Carolina. In January, 1862, the regiment reported 493 present for duty, sustained 29 casualties at Fishing Creek, and lost fifty-one percent of the 220 at Murfreesboro. It had 71 disabled at Chickamauga and in December, 1863, totalled 236 men and 173 arms. Only a remnant surrendered in April, 1865. The field officers were Colonels William P. Bishop, Samuel Powel, and Horace Rice; Lieutenant Colonels Reuben Arnold and John B. Johnson; and Majors Absalom K. Blevins and Samuel L. McKamy.