sentences:  By the end of 1934, 50,000 German Jews had left Germany, and by the end of 1938, approximately half the German Jewish population had left, among them the conductor Bruno Walter, who fled after being told that the hall of the Berlin Philharmonic would be burned down if he conducted a concert there.Albert Einstein, who was in the United States when Hitler came to power, never returned to Germany; his citizenship was revoked and he was expelled from the Kaiser Wilhelm Society and Prussian Academy of Sciences.Other Jewish scientists, including Gustav Hertz, lost their teaching positions and left the country.