Linda,
Most of my information is related to regiments and brigades rather than individuals.
However, the 14th Texas dismounted cavalry was not at the battle of Shiloh.
As I recall, the Texas units at Shiloh included the 8th Cavalry, 2nd and 9th infantry regiments. I did not see a Jasper N. Curtis on the rosters for these regiments at http://www.itd.nps.gov/cwss/soldiers.cfm. There was a John N. Curtis and a John M Curtis in the 9th Texas infantry.
The only Jasper N Curtis is listed on the roster of the 1st battalion Texas Sharpshooters. This unit was not at Shiloh. However, I believe the 1st battalion and 9th regiment were formed from similar areas of Texas.
http://www.itd.nps.gov/cwss/soldiers.cfm
Curtis, Jasper N.
1st Battalion, Texas Sharpshooters (Burnett's)
Curtis, John N.
9th Regiment, Texas Infantry (Maxey's) (Young's)
http://gen.1starnet.com/civilwar/9thinf.htm
Curtis, John M., age 37, born abt. 1824, Pvt., Co. E, enlisted 26 Sep 1861 at Sanders Creek, Lamar Co., TX