In 1843, after his removal to Göttingen, he began his great "Handwörterbuch der Physiologie mit Rücksicht auf physiologische Pathologie"123.13.24, and brought out the fifth (supplementary) volume in 1852. His only original contributions to this work were on the sympathetic nerve, nerve-ganglia and nerve-endings, and he modestly disclaimed all merit except as being the organizer. While resident in Italy for his health from 1845 to 1847, he occupied himself with research on the electrical organ of the torpedo genus of electric eels and on nervous organization generally; these he published in 1853–1854 ("Neurologische Untersuchungen", Göttingen), and therewith his physiological period may be said to end.