The thought of sleep in 'A la recherche du temps perdu' (Proust)

The narrator in Remembrance both lives his sleeping and observes it, in a perpetually intermediary space between sleep and wakefulness, past and present, where he looks at himself asleep but also at the way he used to look at himself asleep; thus he describes states which, like the carafes in the water of the Vivonne, have some of each other's properties but are not - quite - alike.