His two early books remained unnoticed by the reading public. He first became known to a larger circle through a series of works which aimed at establishing the study of both the physical and mental phenomena of the human organism. He applied the same general principles which had been adopted in the investigation of inorganic phenomena. These later works considered the human organism in its normal and diseased states. They included his "Allgemeine Pathologie und Therapie als mechanische Naturwissenschaften" (1842, 2nd ed., 1848), the articles "Lebenskraft" (1843) and "Seele und Seelenleben" (1846) in Rudolf Wagner's "Handwörterbuch der Physiologie", his "Allgemeine Physiologie des Körperlichen Lebens" (1851), and his "Medizinische Psychologie oder Physiologie der Seele" (1852).