4. The child’s dream is a reaction to an experience of the previous day, which has left behind a regret, a longing, or an unsatisfied wish. _In the dream we have the direct, undisguised fulfilment of this wish._ Now consider our discussion as to the part played by the external or internal somatic stimuli as disturbers of sleep and begetters of dreams. We learnt certain quite definite facts on this point, but this explanation only held good in a small number of dreams. In these children’s dreams there is nothing to indicate the influence of such somatic stimuli; we can make no mistake about it, for the dreams are perfectly comprehensible and each can easily be grasped as a whole. But we need not on that account give up our notion of the stimulus as causing the dream. We can only ask why we forget from the outset that there are _mental_ as well as bodily sleep-disturbing stimuli; surely we know that it is these which are mainly responsible for disturbing the sleep of the grown-up person, in that they hinder him from bringing about in himself the mental condition essential for sleep, i.e. the withdrawal of interest from the outside world. He wishes not to have any interruption in his life; he would prefer to continue working at whatever occupies him, and that is the reason why he does not sleep. The mental stimulus which disturbs sleep is therefore for a child the unsatisfied wish, and his reaction to this is a dream. 5. This takes us by a very short step to a conclusion about the function of dreams. If dreams are the reaction to a mental stimulus their value must lie in effecting a discharge of the excitation so that the stimulus is removed and sleep can continue. We do not yet know how this discharge through the dream is effected dynamically, but we notice already that dreams are not disturbers of sleep (the accusation commonly brought against them), but are guardians and deliverers of it from disturbing influences. True, we are apt to think we should have slept better if we had not dreamed, but there we are wrong: the truth is that without the help of the dream we should not have slept at all, and we owe it to the dream that we slept as well as we did. It could not help disturbing us a little, just as a policeman often cannot avoid making a noise when driving off disturbers of the peace who would wake us.