Grete Natzler

Stan and Olly are mousetrap salesmen hoping to strike it rich in Switzerland, but get swindled out of all their money by a cheesemaker. While working off their hotel debt, Olly falls in love with a chambermaid, Anna, who in reality is a famous opera singer spying on her composer husband, Victor, while he works on his new opera... (imdb)

A mad scientist devises a formula that puts people into a zombie-like trance to do his bidding. (imdb)

In old Heidelberg the marriage of a student to a princess is nearly compromised when the landlady pays his debts from the kindness of her heart. (imdb)

Herr Hoffmann (tenor Richard Tauber) is a famous widowed singer with a young daughter to raise, aided by his faithful manager. They meet a girl and Hoffmann falls for her, reluctant to believe that in fact she is in love with a musician. (imdb)

A 17 year old girl, hustling money as a street musician after being evicted from her family home, is forced to disguise as a boy, is charged with a crime, and causes later confusion due to her double identity.