In part to compete with the small professional law schools, there began a great change in U.S. university legal education. For a short time beginning in 1826 Yale began to offer a complete "practitioners' course" which lasted two years and included practical courses, such as pleading drafting. U.S. Supreme Court justice Joseph Story started the spirit of change in legal education at Harvard when he advocated a more "scientific study" of the law in the 19th century. At the time he was a lecturer at Harvard. Therefore, at Harvard the education was much of a trade school type of approach to legal education, contrary to the more liberal arts education advocated by Blackstone at Oxford and Jefferson at William and Mary. Nonetheless there continued to be debate among educators over whether legal education should be more vocational, as at the private law schools, or through a rigorous scientific method, such as that developed by Story and Langdell. In the words of Dorsey Ellis, "Langdell viewed law as a science and the law library as the laboratory, with the cases providing the basis for learning those 'principles or doctrines' of which law, considered as a science, consists. Nonetheless, into the year 1900 most states did not require a university education (although an apprenticeship was often required) and most practitioners had not attended any law school or college.