A Night at the Opera (film) DVD commentary. But this could not have occurred, because Sam Marx had died in 1933, during pre-production of "Duck Soup", two years before "A Night at the Opera" was released. The rumor arose because Frenchy had had such a cameo appearance in the Marx Brothers' earlier "Monkey Business". There is, however, a reference to the Marx Brothers' mother, Minnie Marx, during the stateroom scene, in which a woman asks, "Is my Aunt Minnie in here?" Part of the concept of casting the Marx Brothers as stowaways on a ship was recycled from "Monkey Business". As Groucho's and Margaret Dumont's characters
Monkey Business (1931 film) in the Paramount promotional film "The House That Shadows Built" (1931). The concept of the Marx Brothers being stowaways on a ship would be repeated in an episode of their radio series "Flywheel, Shyster, and Flywheel" (1933) in the episode "The False Roderick" and would also be recycled in their MGM film "A Night at the Opera" (1935). The essence of Groucho's joke, "Sure, I'm a doctor—where's the horse?" would serve as an integral plot element for their film "A Day at the Races" (1937). Also repeated in that later film would be the uproarious medical examination that Harpo and