 In 1902 he became assistant to the Bacteriologist of the London Hospital, Dr. William Bulloch, later F.R.S., and carried out single-handed the whole diagnostic routine of the Hospital.In 1909, Twort became the superintendent of the Brown Animal Sanatory Institution, a pathology research centre, and remained there for the duration of his career.In 1919 Twort married Dorothy Nony, daughter of Frederick J. Banister, and together they had three daughters and a son.