In 1865 he was made professor of comparative anatomy and medical zoölogy at the University of Pennsylvania. He was transferred in 1878 to the chair of physiology, which he occupied until 1895. In addition to many papers contributed to medical journals, he authored a number of books: * Outlines of Comparative Anatomy and Medical Zoölogy (1867) * Studies in the Facial Region (1874) * An Analysis of the Life Form in Art (1875) * System of Human Anatomy (1880)