On his 100 State St, Chicago stationery. "Dear Mr George: Character is the essence of true greatness. Without Character, learning, wealth and power lose their true value. Very truly yours, Frank Billings." Billings started a teaching career of over forty years in 1881 as assistant lecturer in his alma mater, which later became the Northwestern University Medical School. He joined the faculty of Rush Medical College as professor of medicine in 1898. Appointed dean of the faculty in 1900 he held the two positions until 1924. From 1905 to 1924 he was professor of medicine at the University of Chicago. In this long teaching career he exerted a vital leadership in three of Chicago's medical schools and profoundly influenced their policies. The demonstration of the causal relation of focal infections to systemic disease is Billings's great contribution to medical science.