[165] Various pressures lead to dreams of blood. Thus a friend with a weak heart tells me that when he sleeps on his left side he dreams of blood. In some of these cases it is possible that there are retinal sensations of red.
[166] In the Census of Hallucinations (chapter ix.) it was pointed out by the Psychical Research Society's Committee that hallucinations are specially apt to occur on awakening, or in the state between sleeping and waking; and Parish in his very searching study, Hallucinations and Illusions (Contemporary Science Series), has further developed this fact and insisted on its significance.
[167] Dr. Johnson's remark on this point has often been quoted. He dreamed that he had been worsted in a verbal argument, and was thereby much mortified. 'Had not my judgment failed me,' he said, 'I should have seen that the wit of this supposed antagonist, by whose superiority I felt myself depressed, was as much furnished by me as that which I thought I had been uttering in my own character' (Boswell's Johnson, ed. by Hill, vol. iv. p. 5).
[168] Maury, Le Sommeil et les Rêves, 1861, p. 118.
[169] Delbœuf, Le Sommeil et les Rêves, pp. 24, et seq.
[170] Foucault, Le Rêve, p. 137.
[171] Giessler, 'Das Ich im Träume,' Zeitschrift für Psychologie und Physiologie der Sinnesorgane, 1905, Heft 4 and 5, pp. 300 et seq.
[172] See especially Pierre Janet's works, and also those of Morton Prince, Albert Wilson, etc. Flournoy's very elaborate study of Mlle. Helène Smith (Des Indes à la Planète Mars, 1900) is noteworthy. A summary of some important cases of multiple personality will be found in Marie de Manacéïne's Sleep, pp. 127 et seq., and some bibliographical references, ib. p. 151.
[173] J. Milne Bramwell argues ('Secondary and Multiple Personalities,' Brain, 1900) that such cases are not invariably hysterical.
[174] See G. Stanley Hall, 'The Early Sense of Self,' American Journal of Psychology, April 1898. Cooley ('The Early Use of Self-Words by a Child,' Psychological Review, 1909, p. 94) finds that the child distinguishes between itself as (1) body and as (2) self-assertion united with action; it refers to the former as 'Baby,' and to the latter as 'I.'