In Harpo Speaks, Harpo Marx describes a visit to Germany in 1933:
“In Hamburg I saw the most frightening, most depressing sight I had ever seen -- a row of stores with Stars of David and the word ‘Jude’ painted on them, and inside, behind half-empty counters, people in a daze, cringing like they didn’t know what hit them and didn’t know where the next blow would come from. Hitler had been in power only six months, and his boycott was already in full effect. I hadn’t been so wholly conscious of being a Jew since my bar mitzvah. It was the first time since I’d had the measles that I was too sick to eat.
“I got across Germany as fast as I could go. . . .
“Acting in Duck Soup, our last picture for Paramount, was the hardest job I ever did. It was the only time I can remember that I worried about turning in a bad performance. The trouble was not with the working hours, the script, the director, or the falls I had to take (I never used a stunt man or a double). The trouble was Adolf Hitler. His speeches were being rebroadcast in America. Somebody had a radio on the set, and twice we suspended shooting to listen to him scream. Hindenburg had died. Hitler was now absolute dictator of Germany. He threatened to scrap the Versailles Treaty and create a German navy and air force. He threatened to grab off Austria and part of Czechoslovakia. He threatened to go beyond the boycott and revoke the citizenship of all Jews.
“I never knew until then what the emotion of pure anger was like, how it felt to be sore enough to want to hit somebody in cold blood. A lot of people I knew were shocked that I was so shocked. Nothing would really come of the dictator’s threats, they said. He was all bluff and hot air. His act was nothing more than a bad imitation of that other comic, Mussolini.
“I knew better. I had seen faces, those faces in Germany, that most other people had not seen.”