Studied were (1) the evolving use of the microscope in science education, and (2) its relationship to the changing teaching methods, content, and emphases of science courses and to the prevailing philosophies of education of nineteenth century American colleges. To establish the necessary background, the evolution and availability of the microscope and its role in foreign universities and American medical schools were examined. The advent of the microscope into American colleges during the eighteenth century was reviewed. Nineteenth century philosophies of education and their effect on liberal arts college curricula were examined. Uses of the microscope were classified according to the methods of teaching science: (1) lecture-demonstration, (2) the analytic-objective, and (3) laboratory. Findings show that (1) low priced quality student microscopes were available in Europe and the United States after 1850, (2) German institutions used it for teaching in 1820, (3) American medical schools rarely used it before 1870, and only a few of the better schools did after 1870, and (4) scientific schools and teacher training colleges introduced it as they were founded, but liberal arts schools did not until after 1870. (BC)