William E. Pearson served as a private in the 5th Alabama Battalion until he became an Assistant Surgeon on January 19, 1862, according to his CSR and other sources. However, a previous post stated that Pearson became an Assistant Surgeon of the 5th Alabama Battalion - a reasonable assumption, but apparently incorrect. He actually became an Assistant Surgeon of the 1st Tennessee Infantry (Turney's) as confirmed by his CSR under that regiment, as well as his biography in Biographical and Historical Memoirs of Mississippi (Chicago: The Goodspeed Publishing Company, 1891), vol. II, p. 574. It so happens that both the 1st Tennessee and 5th Alabama Battalion were part of the same brigade, Archer's, so it's possible that Pearson might still tend to wounded men of the 5th Alabama Battalion, which would add to the confusion. But the record should be set straight.

Pearson attended Franklin College in Tennessee (not to be confused with Franklin College in Georgia, which became the University of Georgia), and then attended medical schools in Charleston, SC and New Orleans, according to the aforementioned biography. The former is probably the Medical School of South Carolina, but I cannot confirm it. I suppose the latter is the University of Louisiana's Medical Department (now Tulane), but I cannot confirm that fact either. He may have attended medical lectures at both locations without being awarded a M.D. degree.