that on other subjects, I must ask my readers to rest content provided no fundamental fact or important viewpoint be lost in my description.
Until recently most authors have been led to treat the subjects of sleep and dream in the same connection, and with them they have also regularly treated analogous states of psychopathology, and other dreamlike states like hallucinations, visions, &c. In the more recent works, on the other hand, there has been a tendency to keep more closely to the theme, and to take as the subject one single question of the dream life. This change, I believe, is an expression of the conviction that enlightenment and agreement in such obscure matters can only be brought about by a series of detailed investigations. It is such a detailed investigation and one of a special psychological nature, that I would offer here. I have little occasion to study the problem of sleep, as it is essentially a psychological problem, although the change of functional determinations for the mental apparatus must be included in the character of sleep. The literature of sleep will therefore not be considered here.
A scientific interest in the phenomena of dreams as such leads to the following in part interdependent inquiries :
(a) The Relation of the Dream to the Waking State.—The naïve judgment of a person on awakening assumes that the dream—if indeed it does not originate in another world—at any rate has taken the dreamer into another world. The old physiologist, Burdach,8 to whom we are indebted for a careful and discriminating description of the phenomena of dreams, expressed this conviction in an often-quoted passage, p. 474: "The waking life never repeats itself with its trials and joys, its pleasures and pains, but, on the contrary, the dream aims to relieve us of these. Even when our whole mind is filled with one subject, when profound sorrow has torn our hearts or when a task has claimed the whole power of our mentality, the dream either gives us something entirely strange, or it takes for its combinations only a few elements from reality, or it only enters into the strain of our mood and symbolises reality."
L. Strümpell66 expresses himself to the same effect in his Nature and Origin of Dreams (p. 16), a study which is everywhere justly held in high respect: "He who dreams turns
