[47] A somewhat similar mistaken self-detachment may even occur momentarily in the waking condition. Thus Jastrow (The Subconscious, p. 137) refers to the 'lapse of consciousness' of a lady student who, while absorbed in her work, heard outside the door the shuffling of rubber heels such as she herself wore, and said 'There goes——,' naming herself. That delusion was no doubt due to the eruption of a dream-like state of distraction. As regards the visual phantasm of the self (which has sometimes been seen by men of very distinguished intellectual power) it may be noted that it is favoured by the conditions of dream life. Our dream imagery is all pictural, sometimes even to dream consciousness, and to see oneself in the picture is, therefore, not so very much more remarkable than it is in waking life to come upon oneself among a bundle of photographs.
[48] As regards the significance of snakes in dreams, it may be remarked that the followers of Freud regard them as being, in the dreams of women, as they are in the speech and myths of primitive peoples, erotic symbols (e.g. Karl Abraham, Traum und Mythus, 1909, p. 19). It must be remembered, however, that this erotic symbolism is but a small part of the emotional interest aroused by snakes which are an extremely common source of fear, especially in the young. See e.g. Stanley Hall, 'A Study of Fears,' American Journal of Psychology, 1897, pp. 205 et seq.
[49] It may even occur that a person partly wakes up, perceives what is going on around him, converses about it, falls asleep again, and imagines in the morning that the whole episode was a dream. Hammond, who also denies that we can dream we are dreaming, gives a case in illustration (Treatise on Insanity, p. 190).
[50] The vision of the dream world we thus attain corresponds exactly to the philosophy of life set forth by Jules de Gaultier, perhaps the most subtle and original of living thinkers; according to Gaultier the psychic improvisation which has created the spectacle of the world has, as it were, sworn 'never to recognise itself beneath the masks it has assumed, in order to retain the joy of an unending play of the unforeseen.'
[51] Dissociation may be defined as a condition in which, in the words of Tannery (Revue Philosophique, October 1898), 'the various organisms of the brain which in the waking state accomplish distinct functions with satisfactory agreement are, on the contrary, in a state of semi-independence.' There is, in Greenwood's words (Imagination in Dreams, p. 41), a 'loosening of mental bonds,' corresponding to the relaxation of muscular tension which also occurs before going to sleep.
[52] Edmund Parish, Hallucinations and Illusions: A Study of the Fallacies of Perception (Contemporary Science Series), 1897. It is significant to observe that in hysteria, which may be regarded as presenting a condition somewhat analogous to sleep, dissociation also occurs. 'Hysteria,' says Janet (The Major Symptoms of Hysteria, 1907, p. 332), one of the greatest authorities, 'is a form of mental depression characterised by the retraction of the field of personal consciousness and a tendency to the dissociation and emancipation of the system of ideas and functions that constitute personality.'
[53] The theories of attention are lucidly and concisely set forth by Nayrac, 'Le Processus et le Mécanisme de l'Attention,' Revue Scientifique, 7th April 1906.
[54] G. F. Stout, Analytic Psychology, vol. ii. p. 112. In the Dictionary of Philosophy and Psychology, again, Stout and Baldwin define apperception as 'the process of attention in so far as it involves interaction between the presentation of the object attended to, on the one hand, and the total preceding conscious content, together with pre-formed mental dispositions, on the other hand.'
[55] A very similar state of things occurs in some forms of insanity, especially in the less profound states of mental confusion, when, as Bolton remarks ('Amentia and Dementia,' Journal of Mental Science, July 1906, p. 445), we find 'certain associated remnants of former experience combined into a sequence according to the normal laws of mental association.'
[56] Although I reached this conclusion independently, as a result of the analysis of dream experiences, I find that it was set forth at a much earlier period by Wundt. 'Men are accustomed to regard most of the phantasms of dreams as hallucinations,' he writes (Grundzüge der Physiologischer Psychologie, vol. iii.), 'but most dream representations are apparently illusions, initiated by the slight sensory impressions which are never extinguished in sleep.' Weygandt, in his brief but excellent book, Entstehung der Traäme, fully adopts this view, although I scarcely think he is always successful in his attempts to demonstrate it by his own dreams; such demonstration is necessarily often difficult or impossible because, apart from the dream itself, we seldom know what sensory impressions are persisting in our sleep. C. M. Giessler (Die Physiologische Beziehungen der Traumvorgänge, 1896, p. 2), who also proceeds from Wundt, likewise regards dreams as in general the more or less orderly and successive revival of psychic vestiges of waking life, conditioned by inner or outer excitations. Tissié (in Les Rêves, 1898), again, declares that 'dreams of purely psychic origin do not exist,' and Beaunis (American Journal of Psychology, July-October 1903) also believes that all dreams need an internal or external stimulus from the organism.