I have 25 years' researching a War of 1812 ancestor, but would very much like to begin searching for a possible picture of another ancesor who was a Civil War veteran. He was a Union Surgeon from Tennesse, served in the 9th and 11th Cavalry, and is buried in Arlington Cemetary. Any and all advice would be appreciated; I have no idea where to start to find a potential photograph. Thanks you for your ocnsideration.