The great load of mental agony which had been lifted up and held aloof by the daily applied power of opium sank back upon my heart like a crushing weight.

Then, too, my physical sufferings were extreme; an indescribable irritation, a general uneasiness tormented me incessantly.

I can only think of it as a total disarrangement of the whole nervous system, the jarring of all the thousand chords of sensitiveness, each nerve having its own particular pain .-- ( Essay on the Effects of Opium, London, 1763.) "De Quincey, in his wild, metaphysical, and eloquent, yet, in many respects, fancy sketch, considers the great evil resulting from the use of opium to be the effect produced upon the mind during the hours of sleep, the fearful inquietude of unnatural dreams.

My own dreams have been certainly of a different order from those which haunted me previous to my experience in opium eating.

But I cannot easily believe that opium necessarily introduces a greater change in the mind's sleeping operations, than in those of its wakefulness.
"At one period, indeed, while suffering under a general, nervous debility, from which I am even now but partially relieved, my troubled and broken sleep was overshadowed by what I can only express as 'a horror of thick darkness.' There was nothing distinct or certain in my visions, all was clouded, vague, hideous; sounds faint and awful, yet unknown; the sweep of heavy wings, the hollow sound of innumerable footsteps, the glimpse of countless apparitions, and darkness falling like a great cloud from heaven.
"I can scarcely give you an adequate idea of my situation in these dreams, without comparing it with that of the ancient Egyptians while suffering under the plague of darkness.