I would like to know if any else has heard this anecdote and can tell me who the parties involved were and if the story is true or an urban myth.
Two famous actresses, circa 1930s or 40s, happen to arrive at a night spot at the same time. Actress #1 holds open the door and says, “Age before beauty.”
Actress #2 sweeps on in while commenting, “And pearls before swine!”
It’s a great story and somehow I want it to be true!
Attributed to Dorothy Parker.
If it did happen, it wasn’t between two actresses. The quote is attributed (but according to Wikipedia, not confirmed) to Dorothy Parker, said to Clare Boothe Luce.
Both women deny this ever happened. It’s simple one of those stories about “Did you hear what Dorothy Parker said.”
I should have guessed it would be attributed to Dorothy Parker! Such wit, such zingers!
“You can lead a whore to culture…”
On a related Dorothy Parker note, when discussing Rosie O’Donnell’s latest tirade about how she lost all those millions on bringing the musical TABOO to Broadway when the theatre community didn’t support her (and the absolute crappy show), one poster observed: You can lead a horticulture… 
“the T is silent …”
Yeah, yeah, and, “Here’s a $20, Loretta, go fuck yourself.”
The “pearls before swine” crack is also attributed to Bea Lillie.
There was a long SDMB thread from several years ago in which we tried to verify the supposed review Parker gave to a book (“This is not a book to be tossed aside lightly. It should be thrown with great force.”) It’s quoted in a number of places, but we couldn’t find anywhere that the review actually appeared. It’s still possible that it’s a review in some obscure place or that it’s just a remark she made to someone, but it’s more likely that it’s a joke that’s become attached to Parker.
Dorothy Parker’s supposed epitaph: “Pardon my dust.”
Her critique of Katherine Hepburn’s acting: “Her emotional range ran the gamut from A to B.”
Said of a slutty acquaintance who broke a leg in London: “She must have done it sliding down a barrister.”
Also attributed to Parker re CBL:
Matron: “Claire Booth Luce is so kind to her inferiors.”
DP: “Wherever does she find them?”