Hi friends -
one of my ggg-uncles, Peter Owen Simmons, from the Thomasville, Oregon Co. Missouri area was a physician before and after the war.
He also served in Fristoe's Missouri Cavalry, CSA (lots of northcentral and northeast Arkansas men were in the unit as well).
There is not any indication on his scant CSR docs whether or not he was something more than a man in the ranks (he is listed as a Private). I suppose he could have performed medically on an _ad hoc_ level (assistant or medic?) or perhaps he was conscripted??
Since his brothers, father, and inlaws were impacted by the so-called "swamp fight" that occured on their land north of Salem, Fulton Co. AR (see URL below) during March of 1862, I suspect he very well could have enlisted however...