There's a passage in Babylon by Victor Pelevin (at on page 116: "As far as I am aware, the most profound revelation ever to visit a human being under the influence of drugs was occasioned by a critical dose of ether. The recipient summoned up the strength to write it down, even though it cost a supreme effort. What he wrote was: 'The universe is permeated by a smell of oil'".

I'm sure this is a reference and I've read it before. Eco maybe? It's bugging me.