The appearance of his "magnum opus", "Handbuch der Physiologie des Menschen", between 1833 and 1840 (translated into English as "Elements of Physiology" by William Baly, and published in London 1837–1843) marked the beginning of a new period in the study of physiology. In it, for the first time, the results of human and comparative anatomy, as well as of chemistry and other departments of physical science, and tools like the microscope, were brought to bear on the investigation of physiological problems.