Marcel Proust question

Hello people!
I really hope that some of you can help me.

Here is a quote by Marcel Proust:
"The real voyage of discovery consists not in seeking new landscapes, but in having new eyes."

I think that a lot of people know this quote.
And my question is: Could anybody tell me in which book of Proust I can find it?
I already looked like half an hour in Google, but I cant find any source.
It's really important to me.

Thank you guys already!

Lot of Greets from Germany!

Dilara