Professor D.M. Bristol
Professor D.M. Bristol's is famous for his horse and mule training, specifically his "Eques-Curriculum" (Also "Equescurriculum") which operated from 1885-1891, and Prescott's Great Eastern in 1896. He died May 11, 1926 at age 78 at the home of his son, Exeter Bristol.
-- From "Olympians of the Sawdust Circle: A Biographical Dictionary of the Nineteenth Century American Circus"
By William L. Slout