Even in our times there seems to be no lack of authenticated examples of such diagnostic performances on the part of the dream. Thus Tissié cites from Artigues (Essai sur la Valeur séméiologique des Réves), the history of a woman of forty-three years, who, during several years of apparently perfect health, was troubled with anxiety dreams, and in whom medical examination later disclosed an incipient affection of the heart to which she soon succumbed.
Serious disturbances of the internal organs apparently act as inciters of dreams in a considerable number of persons. Attention is quite generally called to the frequency of anxiety dreams in the diseases of the heart and lungs; indeed this relation of the dream life is placed so conspicuously in the foreground by many authors that I shall here content myself with a mere reference to the literature. (Radestock, Spitta, Maury, M. Simon, Tissié.) Tissié even assumes that the diseased organs impress upon the dream content their characteristic features. The dreams of persons suffering from diseases of the heart are generally very brief and terminate in a terrified awakening; the situation of death under terrible circumstances almost always plays a part in their content. Those suffering from diseases of the lungs dream of suffocation, of being crowded, and of flight, and a great many of them are subject to the well-known nightmare, which, by the way, Boerner has succeeded in producing experimentally by lying on the face and closing up the openings of the respiratory organs. In digestive disturbances the dream contains ideas from the sphere of enjoyment and disgust. Finally, the influence of sexual excitement on the dream content is perceptible enough in every one's experience, and lends the strongest support to the entire theory of the dream excitation through organic sensation.
Moreover, as we go through the literature of the dream, it becomes quite obvious that some of the authors (Maury, Weygandt) have been led to the study of dream problems by the influence of their own pathological state on the content of their dreams.
The addition to dream sources from these undoubtedly established facts is, however, not as important as one might be led to suppose; for the dream is a phenomenon which occurs in healthy persons—perhaps in all persons, and every night—and a pathological state of the organs is apparently not one of its indispensable conditions. For us, however, the question is not whence particular dreams originate, but what may be the exciting source for the ordinary dreams of normal persons.
But we need go only a step further to find a dream source which is more prolific than any of those mentioned above, which indeed promises to be inexhaustible in every case. If it is established that the bodily organs become in sickness an exciting source of dreams, and if we admit that the mind, diverted during sleep from the outer world, can devote more attention to the interior of the body, we may readily assume that the organs need not necessarily become diseased in order to permit stimuli, which in some way or other grow into dream pictures, to reach the sleeping mind. What in the waking state we broadly perceive as general sensation, distinguishable by its quality alone, to which, in the opinion of the physicians, all the organic systems contribute their shares—this general sensation at night attaining powerful efficiency and becoming active with its individual components—would naturally furnish the most powerful as well as the most common source for the production of the dream presentations. It still remains, however, to examine according to what rule the organic sensations become transformed into dream presentations.
The theory of the origin of dreams just stated has been the favourite with all medical authors. The obscurity which conceals the essence of our being—the "moi splanchnique," as Tissié terms it—from our knowledge and the obscurity of the origin of the dream correspond too well not to be brought into relation with each other. The train of thought which makes organic sensation the inciter of the dream has besides another attraction for the physician, inasmuch as it favours the etiological union of the dream and mental diseases, which show so many agreements in their manifestations, for alterations in the organic sensations and excitations emanating from the inner organs are both of wide significance in the origin of the psychoses. It is therefore not surprising that the theory of bodily sensation can be traced to more than one originator who has propounded it independently.
A number of authors have been influenced by the train of ideas developed by the philosopher Schopenhauer in 1851. Our conception of the universe originates through the fact that our intellect recasts the impressions coming to it from without in the moulds of time, space, and causality. The sensations from the interior of the organism, proceeding from the sympathetic nervous system, exert in the day-time an influence on our mood for the most part unconscious. At night, however, when the overwhelming influence of the day's impressions is no longer felt, the impressions pressing upward from the interior are able to gain attention—just as in the night we hear the rippling of the spring that was rendered inaudible by the noise of the day. In what other way, then, could the intellect react upon these stimuli than by performing its characteristic function? It will transform the stimuli into figures, filling space and time, which move at the beginning of causality; and thus the dream originates. Scherner, and after him Volkelt, attempted to penetrate into closer relations between physical sensations and dream pictures; but we shall reserve the discussion of these attempts for the chapter on the theory of the dream.
In a study particularly logical in its development, the psychiatrist Krauss found the origin of the dream as well as of deliria and delusions in the same element, viz. the organically determined sensation. According to this author there is hardly a place in the organism which might not become the starting point of a dream or of a delusion. Now organically determined sensations "may be divided into two classes: (1) those of the total feeling (general sensations), (2) specific sensations which are inherent in the principal systems of the vegetative organism, which may be divided into five groups: (a) the muscular, (b) the pneumatic, (c) the gastric, (d) the sexual, (e) the peripheral sensations (p. 33 of the second article)."
The origin of the dream picture on the basis of the physical sensations is conceived by Krauss as follows: The awakened sensation evokes a presentation related to it in accordance with some law of association, and combines with this, thus forming an organic structure, towards which, however, consciousness does not maintain its normal attitude. For it does not bestow any attention on the sensation itself, but concerns itself entirely with the accompanying presentation; this is likewise the reason why the state of affairs in question should have been so long misunderstood (p. 11, &c.). Krauss finds for this process the specific term of "transubstantiation of the feeling into dream pictures" (p. 24).
That the organic bodily sensations exert some influence on the formation of the dream is nowadays almost universally acknowledged, but the question as to the law underlying the relation between the two is answered in various ways and often in obscure terms. On the basis of the theory of bodily excitation the special task of dream interpretation is to trace back the content of a dream to the causative organic stimulus, and if we do not recognise the rules of interpretation advanced by Scherner, we frequently find ourselves confronted with the awkward fact that the organic exciting source reveals itself in the content of the dream only.
A certain agreement, however, is manifested in the interpretation of the various forms of dreams which have been designated as "typical" because they recur in so many persons with almost the same contents. Among these are the well-known dreams of falling from heights, of the falling out of teeth, of flying, and of embarrassment because of being naked or barely clad. This last dream is said to be caused simply by the perception felt in sleep that one has thrown off the bedcover and is exposed. The dream of the falling out of teeth is explained by "dental irritation," which does not, however, of necessity imply a morbid