E. V. THORNTON is listed in Marilyn Hambrick Sickel's book entitled "Prairie County Arkansas Cemetery Inscriptions" as being the father of John Milton THORNTON.
John Milton THORNTON was the second of three sons born to Augustus Erastus THORNTON and Elizabeth Jane KIRK.
Augustus was born about 1830 in North Carolina and Elizabeth was born 7 Oct 1830 in Hardeman County, Tennessee. The couple married 17 Oct 1854 in Marshall County, Mississippi where Elizabeth's father Allen Louis KIRK had moved in the late 1840s.Following their marriage, they moved to McNairy County, Tennessee where their first two sons, Augustus Hannibal and John Milton were born in 1855 and 1857 respectively. Their third son, William Christopher Wright THORNTON was born in Prairie County, Arkansas in Sep 1859.I have not been able to find Augustus and Elizabeth's family on the 1860 U.S. Federal Census and by 1870, Elizabeth was a widow.She finished her life in Prairie County where many of their descendants still live.
If Augustus Erastus THORNTON is the same person as the E.V. THORNTON in your photograph, then I'm sure the THORNTON family in Prairie County, Arkansas would be interested in the picture.