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Related to delirium: delirium tremens
See: insanity

DELIRIUM, med.jur. A disease of the mind produced by inflammations, particularly in fevers, and other bodily diseases.
     2. It is also occasioned by intoxicating agents.
     3. Delirium manifests its first appearance "by a propensity of the patient to talk during sleep, and a momentary forgetfulness of his situation, and of things about him, on waking from it. And after being fully aroused, however, and his senses collected, the mind is comparatively clear and tranquil, till the next slumber, when the same scene is repeated. Gradually the mental disorder becomes more intense, and the intervals between its returns of shorter duration, until they are scarcely, or not at all perceptible. The patient lies on his back, his eyes, if open, presenting a dull and listless look, and is almost constantly talking to himself in a low, muttering tone. Regardless of persons or things around him and scarcely capable of recognizing them when aroused by his attendants, his mind retires within itself to dwell upon the scenes and events of the past, which pass before it in wild and disorderly array, while the tongue feebly records the varying impressions, in the form of disjointed, incoherent discourse, or of senseless rhapsody. In the delirium which occurs towards the end of chrome diseases, the discourse is often more coherent and continuous, though the mind is no less absorbed in its own reveries. As the disorder advances, the voice becomes more indistinct, the fingers are constantly picking at the bed-clothes, the evacuations are passed insensibly, and the patient is incapable of being aroused to any further effort of attention. In some cases, delirium is attended with a greater degree of nervous and vascular excitement, which more or less modifies the abovementioned symptoms. The eyes are open, dry, and bloodshot, intently gazing into vacancy, as if fixed on some object which is really present to the mind of the patient; the skin is hotter and dryer; and he is more restless and intractable. He talks more loudly, occasionally breaking out into cries and vociferation, and tosses about in bed, frequently endeavoring to get up, though without any particular object in view." Ray, Med. Jur. Sec. 213.
     4. "So closely does delirium resemble mania to the casual observer, and so important is it that they should be distinguished from each other, that it may be well to indicate some of the most common and prominent features of each. In mania, the patient recognizes persons and things, and is perfectly conscious of, and remembers what is passing around him. In delirium, he can seldom distinguish one person or thing from another, and, as if fully occupied with the images that crowd upon his memory, gives no attention to those that are presented from without. In delirium, there is an entire abolition of the reasoning power; there is no attempt at reasoning at all; the ideas are all and equally insane; no single train of thought escapes the morbid influence, nor does a single operation of the mind reveal a glimpse of its natural vigor and acuteness. In mania, however false and absurd the ideas may be, we are never at a loss to discover patches of coherence, and some semblance of logical sequence in the discourse. The patient still reasons, but he reasons incorrectly. In mania, the muscular power is not perceptibly diminished, and the individual moves about with his ordinary ability. Delirium is invariably attended with great muscular debility; and the patient is confined to bed, and is capable of only a momentary effort of exertion. In mania, sensation is not necessarily impaired and, in most instances, the maniac sees, bears, and feels with all his natural acuteness. In delirium, sensation is greatly impaired, and this avenue to the understanding seems to be entirely closed. In mania, many of the bodily functions are undisturbed, and the appearance of the patient might not, at first sight, convey the impression of disease. In delirium, every function suffers, and the whole aspect of the patient is indicative of disease. Mania exists alone and independent of any other disorder, while delirium is only a symptom or attendant of some other disease. Being a symptom only, the latter maintains certain relations with the disease on which it depends; it is relieved when that is relieved, and is aggravated when that increases in severity. Mannia, though it undoubtedly tends to shorten life, is not immediately dangerous; whereas the disease on which delirium depends, speedily terminates in death, or restoration to health. Mania never occurs till after the age of puberty; delirium attacks all periods alike, from early childhood to extreme old age." Id. Sec. 216.
     5. In the inquiry as to the validity of testamentary dispositions, it is of great importance, in many cases, to ascertain whether the testator labored under delirium, or whether he was of sound mind. Vide Sound mind; Unsound mind; 2 Addams, R. 441; 1 Addams, Rep. 229, 383; 1 Hagg. R. 577; 2 Hagg. R. 142; 1 Lee, Eccl. R. 130; 2 Lee, Eccl. R. 229; 1 Hag. Eccl. Rep. 256.

References in classic literature ?
With a transport of glee, I mauled the unresisting body, tasting delight from every blow; and it was not till weariness had begun to succeed, that I was suddenly, in the top fit of my delirium, struck through the heart by a cold thrill of terror.
He has had some fearful shock, so says our doctor, and in his delirium his ravings have been dreadful, of wolves and poison and blood, of ghosts and demons, and I fear to say of what.
I was somewhat giddy from turning round so often; at moments it seemed to me that I was in delirium.
His warm and fickle imagination, which in Gascony had rendered formidable to young chambermaids, and even sometimes their mistresses, had never dreamed, even in moments of delirium, of half the amorous wonders or a quarter of the feats of gallantry which were here set forth in connection with names the best known and with details the least concealed.
In fact, although, throughout your illness and delirium, I scarcely left your side for a moment, I cannot think how I contrived to do the many things that I did.
The delirium which it created had effervesced away.
Young souls, in such pleasant delirium as hers are as unsympathetic as butterflies sipping nectar; they are isolated from all appeals by a barrier of dreams--by invisible looks and impalpable arms.
I had been excited and in action all day, and had tasted no food since eight that morning; besides, for a fortnight past, I had known no rest either of body or mind; the last few hours had been a sweet delirium, it would not subside now, and till long after midnight, broke with troubled ecstacy the rest I so much needed.
He had a quick and fiery temper too, which, when thoroughly roused, transported him into a state bordering on delirium.
Her delirium and sickness were not likely to make her forget what she had done in bringing me De Griers' letter.
It was the wild dream of an opium smoker, a vision of delirium.
At first Tarzan would eat nothing, but rolled and tossed in a wild delirium of fever.