- Miss Kitty: [Sitting together in the Long Branch] What is it, anyhow?
- Doc: Oh, well, it's nitrous oxide. It's a... it's an anesthetic is what it is. It's also an intoxicant, and pretty dangerous if you get too much of it.
- Miss Kitty: Well in other words, you don't recommend that we start using it here instead of whiskey, huh?
- Marshal Matt Dillon: Listen, the whiskey you serve here is dangerous enough.
- Miss Kitty: Oh? Except when it's on the house!