Dreams and nightmares prove that our brains work while we sleep. But quite apart from them too, we can prove in many ways that it works while we are asleep. For instance, a man may go to bed trying to solve some problem in science, or to invent a new combination of the pieces in chess, or to find out how a crime was committed, or to write a tune of a song, or to do thousand other things of that kind – and in the morning he may wake and find that during the night, while he was asleep the brain has dome everything he wanted. A great poet once composed a poem in his sleep, and wrote it out the next morning. Sometimes, when the brain has done its work it will wake the man up, and if one is to be awakened at night, that is the nicest way in which it can happen. The French have a very good proverb which expresses this very well. It is, La nuit porte conseil – the night brings counsel.