Psychoanalytic experience has shown that the mechanism of dreams is closely related to that of phobias, obsessions, delusions, and other psychoneurotic and psychotic symptoms. Therefore the study of dreams is important for psychiatry.

Dreams, regarded as a psychic process, present some well-known peculiarities. In dreams things are sometimes recalled which are inaccessible to memory in the waking state. One of the sources of such forgotten material, recalled in dreams, is in the events of childhood. In the selection of the reproduced material stress is laid in dreams not only on the most significant, but also on trivial and indifferent reminiscences. Among dream stimuli are to be mentioned sensory impressions (noises, chilling of exposed parts of the body, subjective sensations), organic physical excitations (cardiac, pulmonary, digestive, uro-genital disturbances in disease and in health), and psychic exciting sources (events of waking hours). Dreams are apt to be quickly forgotten on waking. Sleeping dreams differ from day dreaming in that their character is hallucinatory and not ideational and in the suspension of the criticism by which they could be distinguished from reality.

1S. Freud. The Interpretation of Dreams. English translation by A. A. Brill. All quotations in this section are from this work.

Perhaps the ablest and most thorough investigation of the subject of dreams has been made by Freud, and he has de-developed a theory which endeavors to explain the above and other peculiarities. His large experience has led him to the following generalization: "When the work of interpretation has been completed the dream may be recognized as the fulfilment of a wish." By interpretation, in this connection, is meant the bringing to light, by psychoanalytic technique, of the latent content of dreams, the starting point in the process being their manifest content.

"There are dreams which are undisguised wish-fulfilments. Wherever a wish-fulfilment is unrecognizable and concealed, there must be present a feeling of repulsion towards this wish, and in consequence of this repulsion the wish is unable to gain expression except in a disfigured state." "We should then assume in each human being, as the primary cause of dream formation, two psychic forces (streams, systems), of which one constitutes the wish expressed by the dream, while the other acts as a censor upon this dream wish, and by means of this censoring forces a distortion of its expression." The above generalization has, accordingly, to be restated as follows: "The dream is the (disguised) fulfilment of a (suppressed, repressed) wish."

Freud is of the opinion that the stimulus for every dream is to be found among the experiences "upon which one has not yet slept," i.e., those of the preceding day; but the material may be selected from all times of life. As regards the latter he states, in fact, that " The deeper one goes in the analysis of dreams, the more often one is put on the track of childish experiences which play the part of dream sources in the latent dream content." "As a rule, of course, a childhood scene is represented in the manifest dream content only by an allusion, and must be extricated from the dream by means of interpretation."

Trivial matters are never, in the opinion of Freud, the subject of dreams: "The dream never concerns itself with trifles; we do not allow ourselves to be disturbed in our sleep by matters of slight importance. Dreams which are apparently harmless turn out to be sinister if one takes pains to interpret them." "A displacement - let us say of the psychic accent - has taken place, until ideas that are at first weakly charged with intensity, by taking over the charge from ideas which have a stronger initial intensity, reach a degree of strength which enables them to force their way into consciousness. Such displacements do not at all surprise us when it is a question of the bestowal of affects or of the motor actions in general. The fact that the woman who has remained single transfers her affection to animals, that the bachelor becomes a passionate collector, that the soldier defends a scrap of colored cloth, his flag, with his life-blood, that in a love affair a momentary clasping of hands brings bliss, or that in Othello a lost handkerchief causes a burst of rage - all these are examples of psychic displacement which seem unquestionable to us."

"A connection with what has been recently experienced would form a part of the manifest content of every dream and a connection with what has been most remotely experienced, of its latent content." With reference to somatic sources of dream stimulation, Freud has been led to the opinion that "The essential nature of the dream is not changed by this addition of somatic material to the psychic sources of the dream; it remains the fulfilment of a wish without reference to the way in which its expression is determined by the actual material."

The biological purpose of dreams seems to be to prevent the interruption of sleep by disturbing sensations or thoughts from whatever source they may come. "The dream is the guardian of sleep, not the disturber of it." "Either the mind does not concern itself at all with the causes of sensations, if it is able to do this in spite of their intensity and of their significance, which is well understood by it; or it employs the dream to deny these stimuli; or thirdly, if it is forced to recognize the stimulus, it seeks to find that interpretation of the stimulus which shall represent the actual sensation as a component part of a situation which is desired and which is compatible with sleep." "The wish to sleep, by which the conscious ego has been suspended and which along with the dream-censor contributes its share to the dream, must thus always be taken into account as a motive for the formation of dreams, and every successful dream is a fulfilment of this wish."

In some dreams, notably many typical ones, like that of appearing undressed in public, falling, death of near relatives, the dreamer experiences embarassment, fear, anxiety, or other painful emotion which would seemingly contradict the wish-fulfillment theory. It should be borne in mind, however, that "The wishes represented in the dream as" fulfilled are not always actual wishes. They may also be dead, discarded, covered, and repressed wishes, which we must nevertheless credit with a sort of continuous existence on account of their reappearance in the dream." "The more one is occupied with the solution of dreams, the more willing one must become to acknowledge that the majority of the dreams of adults treat of sexual material and give expression to erotic wishes." "Let us recognize at once that this fact is not to be wondered at, but that it is in complete harmony with the fundamental assumptions of dream explanation. No other impulse has had to undergo so much suppression from the time of childhood as the sex impulse in its numerous components, from no other impulse have survived so many and such intense unconscious wishes, which now act in the sleeping state in such a manner as to produce dreams."

Freud is of the opinion that dreams of nakedness are based on recollections from earliest childhood and are an expression of repressed exhibitionism: "It may be observed in the case of children . . . that being undressed has a kind of intoxicating effect upon them, instead of making them ashamed. They laugh, jump about, and strike their bodies; the mother, or whoever is present, forbids them to do this, and says, 'Fie, that is shameful - you mustn't do that.' Children often show exhibitional cravings; it is hardly possible to go through a village in our part of the country without meeting a two- or three-year-old tot who lifts up his or her shirt before the traveller, perhaps in his honour." The disagreeable emotion accompanying these dreams is the manifestation of an intrapsychic conflict: "According to our unconscious purpose, exhibition is to be continued; according to the demands of the censor, it is to be stopped."

"Dreams of falling are most frequently characterized by fear. Their interpretation, when they occur in women, is subject to no difficulty because women always accept the symbolic sense of falling, which is a circumlocution for the indulgence of an erotic temptation."

Referring to the rather common dreams of the death of a near relative, Freud states: "The death wish of the child towards its brothers and sisters has been explained by the childish egotism, which causes the child to regard its brothers and sisters as competitors." "Dreams of the death of parents predominantly refer to that member of the parental couple which shares the sex of the dreamer, so that the man mostly dreams of the death of his father, the woman of the death of her mother."

"According to my experience, which is now large, parents play a leading part in the infantile psychology of all later neurotics, and falling in love with one member of the parental couple and hatred of the other help to make up that fateful sum of material furnished by the psychic impulses, which has been formed during the infantile period, and which is of such great importance for the symptoms appearing in the later neurosis. But I do not think that psychoneurotics are here sharply distinguished from normal human beings, in that they are capable of creating something absolutely new and peculiar to themselves. It is far more probable, as is shown also by occasional observation upon normal children, that in their loving or hostile wishes towards their parents psychoneurotics only show in exaggerated form feelings which are present less distinctly and less intensely in the minds of most children. Antiquity has furnished us with legendary material to confirm this fact, and the deep and universal effectiveness of these legends can only be explained by the above-mentioned assumption in infantile psychology."

"I refer to the legend of King (Edipus and the drama of the same name by Sophocles. CEdipus, the son of Laius, king of Thebes, and of Jocasta, is exposed while a suckling, because an oracle has informed the father that his son, who is still unborn, will be his murderer. He is rescued, and grows up as the king's son at a foreign court, until, being uncertain about his origin, he also consults the oracle, and is advised to avoid his native place, for he is destined to become the murderer of his father and the husband of his mother. On the road leading away from his supposed home he meets King Laius and strikes him dead in a sudden quarrel. Then he comes to the gates of Thebes, where he solves the riddle of the Sphynx who is barring the way, and he is elected king by the Thebans in gratitude, and is presented with the hand of Jocasta. He reigns in peace and honour for a long time, and begets two sons and two daughters upon his unknown mother, until at last a plague breaks out which causes the Thebans to consult the oracle anew. Here Sophocles' tragedy begins. The messengers bring the advice that the plague will stop as soon as the murderer of Laius is driven from the country.

But where is he hidden? 'Where are they to be found? How shall we trace the perpetrators of so old a crime where no conjecture leads to discovery?' The action of the play now consists merely in a revelation, which is gradually completed and artfully delayed - resembling the work of psychoanalysis - of the fact that CEdi-pus himself is the murderer of Laius, and the son of the dead man and of Jocasta. CEdipus, profoundly shocked at the monstrosities which he has unknowingly committed, blinds himself and leaves his native place. The oracle has been fulfilled."

"Perhaps someone will now object that, although the inimical impulses of children towards their brothers and sisters (or parent) may well enough be admitted, how does the childish disposition arrive at such a height of wickedness as to wish death to a competitor or stronger playmate, as though all transgressions could be atoned for only by the death-punishment? Whoever talks in this manner forgets that the childish idea of 'being dead' has little else but the words in common with our own. The child knows nothing of the horrors of decay, of shivering in the cold grave, of the terror of the infinite Nothing, which the grown up person, as all the myths concerning the Great Beyond testify, finds it so hard to bear in his conception. Fear of death is strange to the child; therefore it plays with the horrible word and threatens another child."