Thomas was educated at Marlborough, and studied medicine at Edinburgh University, where he graduated M.B., C.M. in 1880. He entered practice in Liverpool becoming private assistant to Mr E R Bickersteth, where he remained for several years. His first public appointment was as an assistant physician to the Liverpool Hospital for Diseases of the Chest. He was also the surgeon to the Liverpool police, serving as a much esteemed member of the force, and instrumental in securing an increase in salary for police surgeons in the city. In 1897 he received the appointment of honorary physician to the David Lewis Northern Hospital, an appointment he held until his death. In addition, Thomas became a valued friend and physician to some of the Liverpool nursing institutions and philanthropic agencies, and acted as one of the Liverpool Representatives at the Representative Meetings of the British Medical Association. In medico-political matters he did yeoman service. At the outbreak of war, his health was already starting to fail him and he was not able to do his share as Major, attached to the 1st Western General Hospital, in attending to the sick and wounded soldiers. Shortly after he felt himself compelled to resign, with an understanding that after a period of rest he would be able to resume his duties again. Thomas was described as shy by nature with a retiring disposition, who was inclined to hide his light under a bushel, and who did not always readily reveal his knowledge, yet had an extensive knowledge of medical literature and the classics. He was a well-equipped physician, taking a great interest in diseases of the skin, whereby his option on any obscure cases was generally sought. He was the husband of Mary Wimble - they had two children, a son and a daughter.