If you were to wake up one morning, with a clear conscience and a healthy body, and yet at the instant at opening your eyes were to become aware of a faint feeling of depression and discomfort, as though there were a headache somewhere in the room; and if at the same time you found your waking thoughts straying in the direction of self-analysis accompanied by a strange distaste for the lot of mortal man;if, as I say, all this were to happen to you, you would of course realise at once that it must be Sunday.