Mr. Sturkey,
This is a bit later but as late as the late 1890's it appears that only two years of formal schooling was still the requisite. I have a 2gr-uncle that became a doctor then. I can't remember the exact date on his license as I don't know which CD I have it on but just prior to 1900 his license says he has one year of studies at the Univ. of Tenn. and one at Tulane and somewhere- perhaps on the license- I've seen that he studied with a doctor.
Another relative was assigned to the wards to help as he recuperated from his own wounds in the war and acquired the nickname "doc" along the way.