ugh more easily overlooked.
Professor Huxley relates that he is liable to auditory though not to
visual hallucinations. (See _Elementary Lessons in Physiology_, p. 267.)

[65] See Baillarger, _Memoires de l'Academie Royale de Medicine_, tom.
xii. p. 273, _et seq._

[66] See Baillarger, _Annales Medico-Psychologiques_, tom. vi. p. 168
_et seq._; also tom. xii. p. 273, _et seq._ Compare Griesinger, _op.
cit._ In a curious work entitled _Du Demon de Socrate_ (Paris, 1856), M.
Lelut seeks to prove that the philosopher's admonitory voice was an
incipient auditory hallucination symptomic of a nascent stage of mental
alienation.

[67] This is well brought out by Dr. J. Hughlings Jackson, in the papers
in _Brain_, already referred to.

[68] _Friend_, vol. i. p. 248. The story is referred to by Sir W. Scott
in his _Demonology and Witchcraft_.

[69] See E.B. Tylor, _Primitive Culture_, ch. xi.; _cf._ Herbert
Spencer, _Principles of Sociology_, ch. x.

[70] For a fuller account of the different modes of
dream-interpretation, see my article "Dream," in the ninth edition of
the _Encyclopaedia Britannica_.

[71] For a fuller account of the reaction of dreams on waking
consciousness, see Paul Radestock, _Schlaf und Traum_. The subject is
touched on later, under the Illusions of Memory.

[72] For an account of the latest physiological hypotheses as to the
proximate cause of sleep, see Radestock, _op. cit._, appendix.

[73] Plutarch, Locke, and others give instances of people who never
dreamt. Lessing asserted of himself that he never knew what it was to
dream.

[74] The error touched on here will be fully dealt with under Illusions
of Memory.

[75] For a very full, fair, and thoughtful discussion of this whole
question, see Radestock, _op. cit._, ch. iv.

[76] This may be technically expressed by saying that the liminal
intensity (Schwelle) is raised during sleep.

[77] See Wundt, _Physiologische Psychologie_, pp. 188-191.

[78] There is, indeed, sometimes an undertone of critical reflection,
which is sufficient to produce a feeling of uncertainty and
bewilderment, and in very rare cases to amount to a vague consciousness
that the mental experience is a dream.

[79] _Observations on Man_, Part I. ch. iii, sec. 5.

[80] Quoted by Radestock, _op. cit._, p. 110.

[81] _Le Sommeil et les Reves_, p. 132, _et seq._

[82] _Das Leben des Traumes_, p. 369. Other instances are related by
Beattie and Abercrombie.

[83] _