Each cardboard viewer (made in Japan) comes with 3-4 frames of real nitrate film. Almost all are silent, with one of the few sound frames shown below. Some are on amber film stock, all have been stored away 'till this year. The age of the toy (1932) is based on the age of the top frame below because it's the newest one found.
The top vote is Blonde Venus (1932)

Into the Net (1924)
B&W : Serial / Ten episodes
Directed by George B. Seitz
The film is presumed lost.