and breaking of consciousness, at its very focus, is shown in the most unmistakable manner.[197] But many of the most remarkable dreams of dramatic dreamers are due to the same phenomenon, which in an intellectual form is exactly the phenomenon which always makes a dramatic situation effective. Robert Louis Stevenson was an abnormally vivid dreamer, and found the germ of some of the plots of his stories in his dreams; he has described one of his dreams in which the dreamer imagines he has committed a murder; the crime becomes known to a woman who, however, never denounces it; the murderer lives in terror, and cannot conceive why the woman prolongs his torture by this delay in giving him up to justice; only at the end of the dream comes the clue to the mystery, and the explanation of the woman's attitude, as she falls on her knees and cries: 'Do you not understand? I love you.'[198] There is another and very interesting class of dreams in which we find not merely that some memory-groups disappear from consciousness or become merely latent, but also that other memory-groups, latent or even lost to waking consciousness, float into the focus of sleeping consciousness. In other words, we can remember in sleep what we have forgotten awake. We then have what is called the _hypermnesia_, the excessive or abnormal memory, of sleep. There can be little doubt that the two processes--the sinking of some memory-groups and the emergence on the surface of other memory-groups which, so far as waking life is concerned, had apparently fallen to the depths and been drowned--are complementarily related to one another. We remember what we have forgotten because we forget what we remembered. The order of our waking impressions involves a certain tension, that is to say a certain attention, which holds them in our consciousness, and excludes any other order which might serve to bring lost memory-groups to sight. Sometimes we are conscious of a lost memory which is just outside consciousness, but which, with the existing order of our memory-groups, we cannot bring into consciousness. We have the missing name, the missing memory, at the tip of our tongue, we say, but we cannot quite catch it.[199] In dreams apperception is defective, the strain of conscious attention is relaxed, and the conditions are furnished under which new clues and strains may come into action and the missing name glide spontaneously into consciousness. Even the mere approach of sleep, with its accompanying relaxation of attention, may effect this end. Thus I was trying one day to recall the name of the unpleasant Chinese scent, patchouli. The name, though not usually unfamiliar, escaped me. At night, however, just before falling asleep, it spontaneously occurred to me. In the morning, when fully awake, I was again unable to recall it.