Daphne: I used to have the same problem when I was raising show rats.
Niles: You don't mean the nasty, plague-propagating vermin, do you?
Daphne: No. I mean purebred rats. As in Siamese or Himalayan or Husky. My most prized one was an Andalusian Blue named Lady Prissy and she wasn't sick a day in her life. So don't go blaming all rats because of a few bad apples.
Frasier: A few bad apples? Daphne, they spread a disease that nearly wiped out half the population of Europe.
Daphne: Shows what you know. Those were common European brown rats.
Frasier: Yes, but the point is-
Daphne: Oh, no, no, no. I'll sit here and listen to you prattle on about wine and opera. But when it comes to rats, you're in my house.