of correction remains with us.  We may not exercise it, it is true, and thus the illusion will tend to become more or less persistent and recurring; for the same law applies to true and to false perception:  repetition makes the process easier.  But if we only choose to exert ourselves, we can always keep our illusions in a nascent or imperfectly developed stage.  This applies not only to those half-illusions into which we voluntarily fall, but also to the more irresistible passive illusions, and those arising from an over-excited imagination.  Even persons subject to hallucinations, like Nicolai of Berlin, learn to recognize the unreal character of these phantasms.  On this point the following bit of autobiography from the pen of Coleridge throws an interesting light.  “A lady (he writes) once asked me if I believed in ghosts and apparitions.  I answered with truth and simplicity, No, madam, I have seen far too many myself."[68] However irresistible our sense-illusions may be, so long as we are under the sway of particular impressions or mental images, we can, when resolved to do so, undeceive ourselves by carefully attending to the actual state of things about us.  And in many cases, when once the correction is made, the illusion seems an impossibility.  By no effort of imagination are we able to throw ourselves back into the illusory mental condition.  So long as this power of dispelling the illusion remains with us, we need not be alarmed at the number and variety of the momentary misapprehensions to which we are liable.

CHAPTER VII.

DREAMS.

The phenomena of dreams may well seem at first sight to form a world of their own, having no discoverable links of connection with the other facts of human experience.  First of all, there is the mystery of sleep, which quietly shuts all the avenues of sense and so isolates the mind from contact with the world outside.  To gaze at the motionless face of a sleeper temporarily rapt from the life of sight, sound, and movement—­which, being common to all, binds us together in mutual recognition and social action—­has always something awe-inspiring.  This external inaction, this torpor of sense and muscle, how unlike to the familiar waking life, with its quick responsiveness and its overflowing energy!  And then, if we look at dreams from the inside, we seem to find but the reverse face of the mystery.  How inexpressibly strange does the late night-dream seem to a person on waking!  He feels he has been seeing and hearing things no less real than those of waking life; but things which belong to an unfamiliar world, an order of sights and a sequence of events quite unlike those of waking experience; and he asks himself in his perplexity where that once-visited region really lies, or by what magic power it was suddenly and for a moment created for his vision.  In truth, the very name of dream suggests something remote and mysterious, and when we want to characterize some impression or scene which by its passing strangeness filled us with wonder, we naturally call it dream-like.