Subsequently, he became an assistant to Joseph von Mering at the University of Halle, and afterwards worked under neurologist Ludwig Lichtheim in Königsberg. Later he was an assistant to dermatologist Paul Gerson Unna in Hamburg and to internist Ernst Viktor von Leyden in Berlin.
Subsequently, he took on a role as an assistant to Joseph von Mering at the University of Halle, and subsequently worked under neurologist Ludwig Lichtheim in Königsberg. Later he held positions as an assistant to dermatologist Paul Gerson Unna in Hamburg and to internist Ernst Viktor von Leyden in Berlin.