I am getting old. I used to do a trick with a deck of cards that has the number 48 and the number 18 written on the back of the two jokers. I remember liking the trick, but for the life of me I don't remember it's name . Without it's name, I can't look up the instructions in my library. Can anyone help?

Might it have been 43 and 18?

I've seen this called "Whispering Jokers", but I've seen references which suggest the original might be Simon Aronson's "Prior Commitment".

Yes, that's the title; it's in Simon's Try the Impossible.

Thanks to you both. Yes, there it was on shelf. The very first effect in the book. And now I remember why I liked it so much!
Ed

The reference to Aronson's book made me expect some memorization should be involved. But it is not the case. Very good effect indeed.

There's an impromptu version of this trick in Darwin Ortiz' latest book: Lessons in Card Magic. Well worth the read.