Reading in bed

A favorite moment from Oliver Sacks's new book:

Once, while reading Gibbon’s autobiography in bed—this was in 1988, when I was thinking and reading a great deal about deaf people and their use of sign language—I found an amazing description by Gibbon of seeing a group of deaf people in London in 1770, immersed in an animated sign discourse. I immediately thought that this would make a wonderful footnote for the book I was writing, but when I came to reread Gibbon’s description, it was not there. I had hallucinated or perhaps dreamt it, in a flash, between two sentences of text.