Hermann Ludwig Ferdinand von Helmholtz was born in Potsdam in 1821. His father was a teacher of philology and philosophy in the Gymnasium; his mother "a lineal descendant of William Penn." Helmholtz entered on the study of medicine in 1838, in the Royal Medico-Chirurgical Frederich-Wilhelm Institute, in Berlin. He commenced his life work, and published his first paper, in that city in 1842, and remained there till 1847, when he became professor of physiology in Königsberg. Here he remained till 1856, and then took the chair of physiology in Bonn. This he held until 1859, when he became professor of physiology in Heidelberg. He was in Heidelberg for twelve years, and, in 1871, removed to Berlin to assume the chair of physics, a position he held till his death.
Had he done nothing else, the man who gave the ophthalmoscope to the world would be entitled to be classed among