In a morbid condition of the brain, dreams often have an extraordinary distinctiveness, vividness, and extraordinary semblance of reality. At times monstrous images are created, but the setting and the entire process of imagining are so truth-like and filled with details so delicate, so unexpected, but so artistically consistent with the picture as a whole, that the dreamer, were he an artist like Pushkin or Turgenev even, could never have invented them in the waking state. Such sick dreams always remain long in the memory and make a powerful impression on the overwrought and excited nervous system.