A vampire casts no reflection in the glass. That is why Dracula smashed the mirror.
8 seconds sound clip from the Dracula (1931) movie soundboard.
You can hear this line at 00:45:10 in the Blu-ray version of the movie.
Quote context
[...]
- Sometimes they take the form of wolves, but generally of bats.
- Dracula.
- But what's Dracula got to do with wolves and bats?
- A vampire casts no reflection in the glass. That is why Dracula smashed the mirror.
- I don't mean to be rude, but that's the sort of thing I'd expect one of the patients here to say.
- Yes, and that is what your English doctors would say, your police.
- The strength of the vampire is that people will not believe in him.
- Professor, vampires only exist in ghost stories.
[...]