Professor, vampires only exist in ghost stories.

6 seconds sound clip from the Dracula (1931) movie soundboard.

You can hear this line at 00:46:07 in the Blu-ray version of the movie.

Quote context

[...]

- But surely, Professor...

- 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.

- A vampire is a being that lives after its death by drinking the blood of the living. It must have blood or it dies.

- Its power lasts only from sunset to sunrise. During the hours of the day, it must rest in the earth in which it was buried.

- But then, if Dracula were a vampire, he'd have to return every night to Transylvania, and that's impossible.

- Then he must have brought his native soil with him, boxes of it. Boxes of earth large enough for him to rest in.

[...]