4. The child's dream is a reaction to an experience of the day, which has left behind it a regret, a longing or an unfulfilled desire. _The dream brings about the direct unconcealed fulfillment of this wish._ Now recall our discussions concerning the importance of the role of external or internal bodily stimuli as disturbers of sleep, or as dream producers. We learned definite facts about this, but could only explain a very small number of dreams in this way. In these children's dreams nothing points to the influence of such somatic stimuli; we cannot be mistaken, for the dreams are entirely intelligible and easy to survey. But we need not give up the theory of physical causation entirely on this account. We can only ask why at the outset we forgot that besides the physical stimuli there are also psychic sleep-disturbing stimuli. For we know that it is these stimuli that commonly cause the disturbed sleep of adults by preventing them from producing the ideal condition of sleep, the withdrawal of interest from the world. The dreamer does not wish to interrupt his life, but would rather continue his work with the things that occupy him, and for this reason he does not sleep. The unfulfilled wish, to which he reacts by means of the dream, is the psychic sleep-disturbing stimulus for the child. 5. From this point we easily arrive at an explanation of the function of the dream. The dream, as a reaction to the psychic stimulus, must have the value of a release of this stimulus which results in its elimination and in the continuation of sleep. We do not know how this release is made possible by the dream, but we note that _the dream is not a disturber of sleep_, as calumny says, _but a guardian of sleep, whose duty it is to quell disturbances_. It is true, we think we would have slept better if we had not dreamt, but here we are wrong; as a matter of fact, we would not have slept at all without the help of the dream. That we have slept so soundly is due to the dream alone. It could not help disturbing us slightly, just as the night watchman often cannot avoid making a little noise while he drives away the rioters who would awaken us with their noise.