rectly, and our recollection of our dreams is
extraordinarily fragmentary; we do not know how far our dream memory
really extends. Connected with memory of other states is the question of
memory in dreams of previous dream states; occasionally a separate chain
of memory, analogous to a secondary personality, seems to be formed. We
may be also conscious that we have been dreaming, and subsequently,
without intermediate waking, relate as a dream the dream previously
experienced. In spite of the irrationality of dreams in general, it by
no means follows that the earlier and later portions of a dream do not
cohere; we may interpolate an episode and again take up the first
motive, exactly as happens in real life. The strength of the dream
memory is shown by the recurrence of images in dreams; a picture, the
page of a book, or other image may be reproduced before our eyes several
times in the course of a dream without the slightest alteration,
although the waking consciousness would be quite incapable of such a
feat of visualizing. In this connexion may be mentioned the phenomenon
of redreaming; the same dream may recur either on the same or on
different nights; this seems to be in many cases pathological or due to
drugs, but may also occur under normal conditions.

_Personality._--As a rule the personality of the dreamer is unchanged;
but it also happens that the confusion of identity observed with regard
to other objects embraces the dreamer himself; he imagines himself to be
some one else; he is alternately actor and observer; he may see himself
playing a part or may divest himself of his body and wander
incorporeally. Ordinary dreams, however, do not go beyond a splitting of
personality; we hold conversations, and are intensely surprised at the
utterances of a dream figure, which, however, is merely an _alter ego_.
As in the case of Hilprecht (see above) the information given by another
part of the personality may not only appear but actually be novel.

_Supernormal Dreams._--In addition to dreams in which there is a revival
of memory or a rise into consciousness of facts previously only
subliminally cognized, a certain number of dreams are on record in which
telepathy (q.v.) seems to play a part; much of the evidence is, however,
discounted by the possibility of hallucinatory memory. Another class of
dreams (prodromic) is that in which the abnormal bodily states of the
dreamer are brought to his knowledge in sleep, somet