Josee B. also wrote to me about her "Alice-in-Wonderland syndrome" as a child with fever. She remembered feeling "incredibly small or incredibly large and sometimes both at the same time." She also experienced distortions in proprioception, her perception of her own body position: "One evening, I couldn't sleep in my own bed-every time I lay down on it, I would feel I was standing tall." She had a visual hallucination, too: "Suddenly I saw cowboys who were throwing apples at me. I jumped onto my mother's dresser to hide behind a lipstick tube."

Another woman, Ellen R., had visual hallucinations that took on a rhythmic, pulsing quality:

I would "see" a smooth surface, like gla.s.s, or like the surface of a pond.... Concentric rings would spread from the center to the outside edges, as though a pebble had been dropped right in the middle. This rhythm starts slowly [but] ... eventually speeds up, so that the surface is constantly agitated, and as this happens, my own agitation is heightened. Eventually the rhythm slows, the surface smooths out, and I become relieved and calmer myself.

Sometimes in a delirium there may be a deep humming sound that waxes and wanes in a similar way.

While many people describe delirious swellings of body image, Devon B., when feverish, experienced mental or intellectual swellings instead:

What made them so strange was that they weren't sensory hallucinations, but a hallucination of an abstract idea ... a sudden dread of a very, very large and growing number (or a thing, but a thing I never really defined).... I remember pacing up and down the hallway ... in a growing state of panic and horror at an exponentially increasing, impossible number.... My fear was that this number was violating some very basic precept of the world ... an a.s.sumption we hold that absolutely should not be violated.

This letter made me think of the arithmetical deliria which Vladimir Nabokov went through, wrestling with impossibly large numbers, as he described in his autobiography Speak, Memory:

As a little boy, I showed an abnormal apt.i.tude for mathematics, which I completely lost in my singularly talentless youth. This gift played a horrible part in tussles with quinsy or scarlet fever, when I felt enormous spheres and huge numbers swell relentlessly in my aching brain.... I had read ... about a certain Hindu calculator who in exactly two seconds could find the seventeenth root of, say, 3529471145760275132301897342055866171392 (I am not sure I have got this right; anyway the root was 212). Such were the monsters that thrived on my delirium, and the only way to prevent them from crowding me out of myself was to kill them by extracting their hearts. But they were far too strong, and I would sit up and laboriously form garbled sentences as I tried to explain things to my mother. Beneath my delirium she recognized sensations she had known herself, and her understanding would bring my expanding universe back to a Newtonian norm.

Some people feel that the hallucinations and strange thoughts of delirium may provide, or seem to provide, moments of rich emotional truth, as with some dreams or psychedelic experiences. There may also be revelations or breakthroughs of deep intellectual truth. In 1858, Alfred Russel Wallace, who had been traveling the world for a decade, collecting specimens of plants and animals and considering the problem of evolution, suddenly conceived the idea of natural selection during an attack of malarial fever. His letter to Darwin proposing this theory pushed Darwin to publish On the Origin of Species the following year.

Robert Hughes, in the opening of his book on Goya, writes about a prolonged delirium during his recovery from a nearly fatal car crash. He was in a coma for five weeks and hospitalized for almost seven months. In intensive care, he wrote,

One's consciousness ... is strangely affected by the drugs, the intubation, the fierce and continuous lights, and one's own immobility. These give rise to prolonged narrative dreams, or hallucinations, or nightmares. They are far heavier and more enclosing than ordinary sleep-dreams and have the awful character of inescapability; there is nothing outside them, and time is wholly lost in their maze. Much of the time, I dreamed about Goya. He was not the real artist, of course, but a projection of my fears. The book I meant to write on him had hit the wall; I had been blocked for years before the accident.

In this strange delirium, Hughes wrote, a transformed Goya seemed to be mocking and tormenting him, trapping him in some h.e.l.lish limbo. Eventually, Hughes interpreted this "bizarre and obsessive vision":

I had hoped to "capture" Goya in writing, and he instead imprisoned me. My ignorant enthusiasm had dragged me into a trap from which there was no evident escape. Not only could I not do the job; my subject knew it and found my inability hysterically funny. There was only one way out of this humiliating bind, and that was to crash through.... Goya had a.s.sumed such importance in my subjective life that whether I could do him justice in writing or not, I couldn't give up on him. It was like overcoming writer's block by blowing up the building in whose corridor it had occurred.

Alethea Hayter, in her book Opium and the Romantic Imagination, writes that Piranesi, the Italian artist, was "said to have conceived the idea of his engravings of Imaginary Prisons when he was delirious with malaria," a disease he contracted

while he explored the ruined monuments of Ancient Rome ... among the nocturnal miasmas of that marshy plain. He was bound to get malaria; and the delirious visions when they came to him may have owed something to opium as well as to a high temperature, since opium was then a normal remedy for ague or malaria.... The images which were born during his delirious fever were executed and elaborated over many years of fully conscious and controlled labour.

Delirium may produce musical hallucinations, as Kate E. wrote:

I was about eleven, in bed with a high fever, when I heard some heavenly music. I understood it to be a choir of angels, even though I found this odd, as I don't believe in heaven or angels and never have. So I decided it must be coming from Christmas carolers on our front doorstep below. After a minute or so, I realized it was springtime, and that I must be hallucinating.

A number of people have written to me that they have visual hallucinations of music, hallucinating musical notation all over the walls and ceiling. One of them, Christy C., recalled:

As a child, I ran high fevers when sick. With each spell, I would hallucinate. This was an optical hallucination involving musical notes and stanzas. I did not hear music. When the fever was high, I would see notes and clef lines, scrambled and out of order. The notes were angry and I felt unease. The lines and notes were out of control and at times in a ball. For hours, I would try to mentally smooth them out and put them in harmony or order. This same hallucination has plagued me as an adult when feverish.

Tactile hallucinations, too, can come with fever or delirium, as Johnny M. described: "When I had high fevers as a child I had very weird tactile hallucinations ... a nurse's fingers would switch from being beautiful smooth porcelain to rough, brittle-feeling twigs or my bed sheets would go from luscious satin to drenched, heavy blankets."

Fevers are perhaps the commonest cause of delirium, but there may be a less obvious metabolic or toxic cause, as recently happened with a physician friend of mine, Isabelle R. She had had two months of increasing weakness and occasional confusion; finally she became unresponsive and was taken to the hospital, where she had a florid delirium, with hallucinations and delusions. She was convinced that a secret laboratory was hidden behind a picture on the wall of her hospital room-and that I was supervising a series of experiments on her. She was found to have extremely high levels of calcium and vitamin D (she had been taking large doses of these for her osteoporosis), and as soon as these toxic levels dropped, her delirium ceased, and she returned to normal.

Delirium is cla.s.sically a.s.sociated with alcohol toxicity or withdrawal. Emil Kraepelin, in his great 1904 Lectures on Clinical Psychiatry, included the case history of an innkeeper who developed delirium tremens from drinking six or seven liters of wine a day. He became restless and immersed in a dreamlike state in which, Kraepelin wrote,

particular real perceptions ... are mingled with numerous very vivid false perceptions, especially of sight and hearing. As in a dream, a whole series of the most strange and remarkable events take place with occasional sudden changes of scene.... Given the vivid hallucinations of sight, the restlessness, the strong tremors, and the smell of alcohol, we have all the essential features of the clinical condition called delirium tremens.

The innkeeper had some delusions, too, perhaps produced by his hallucinations:

We learn, by questioning him, that he is going to be executed by electricity, and also that he will be shot. "The picture is not clearly painted," he says; "every moment someone stands now here, now there, waiting for me with a revolver. When I open my eyes they vanish." He says that a stinking fluid has been injected into his head and both his toes, which causes the pictures [he] takes for reality.... He looks eagerly at the window, where he sees houses and trees vanishing and reappearing. With slight pressure on his eyes, he sees first sparks, then a hare, a picture, a washstand-set, a half-moon, and a human head, first dully and then in colours.

While deliria such as the innkeeper's may be incoherent, without any theme or connecting thread, other deliria convey the sense of a journey, or a play, or a movie, giving coherence and meaning to the hallucinations. Anne M. had such an experience after she had run a high temperature for several days. She first saw patterns whenever she closed her eyes to go to sleep; she described them as resembling Escher drawings in their sophistication and symmetry:

The initial drawings were geometric but then evolved into monsters and other rather unpleasant creatures.... The drawings were not in color. I was not enjoying this at all because I wanted to sleep. Once a drawing was complete it was copied so all four or six or eight quadrants of my visual field would be full of these identical pictures.

These drawings were succeeded by richly colored images that reminded her of Brueghel paintings. Increasingly, these too became full of monsters and subdivided themselves, polyopically, into a cl.u.s.ter of identical mini-Brueghels.

Then came a more radical change. Anne found herself in the back of "a 1950s Chinese bus on a propaganda tour of Chinese Christian churches." She recalls watching a movie on religious freedom in China projected onto the rear window of the bus. But the viewpoint kept changing-both the movie and the bus suddenly tilted to odd angles, and it was unclear, at one point, whether a church spire she saw was "real," outside the bus, or part of the movie. Her strange journey occupied the greater part of a feverish and insomniac night.

Anne's hallucinations appeared only when she closed her eyes and would vanish as soon as she opened them.2 But other deliria may produce hallucinations that seem to be present in the real environment, seen with the eyes open.

In 1996, I was visiting Brazil when I started to have elaborate narrative dreams with extremely brilliant colors and an almost lithographic quality, which seemed to go on all night, every night. I had gastroenteritis with some fever, and I a.s.sumed that my strange dreams were a consequence of this, compounded, perhaps, by the excitement of traveling along the Amazon. I thought these delirious dreams would come to an end when I got over the fever and returned to New York. But, if anything, they increased and became more intense than ever. They had something of the character of a Jane Austen novel, or perhaps a Masterpiece Theatre version of one, unfolding in a leisurely way. These visions were very detailed, with all the characters dressed, behaving, and talking as they might in Sense and Sensibility. (This astonished me-for I have never had much social sense or sensibility, and my taste in novels inclines more to d.i.c.kens than Austen.) I would get up at intervals during the night, dab cold water on my face, empty my bladder, or make a cup of tea, but as soon as I returned to bed and closed my eyes again I was in my Jane Austen world. The dream had moved on while I was up, and when I rejoined it, it was as if the narrative had continued in my absence. A period of time had pa.s.sed, events had transpired, some characters had disappeared or died, and other new ones were now on stage. These dreams, or deliria, or hallucinations, whatever they were, came every night, interfering with normal sleep, and I became increasingly exhausted from sleep deprivation. I would tell my a.n.a.lyst about these "dreams," which I remembered in great detail, unlike normal dreams. He said, "What's going on? You have produced more dreams in the past two weeks than in the previous twenty years. Are you on something?"

I said no-but then I remembered that I had been put on weekly doses of the antimalarial drug Lariam before my trip to the Amazon, and that I was supposed to take two or three further doses after my return.

I looked up the drug in the Physician's Desk Reference-it mentioned excessively vivid or colorful dreams, nightmares, hallucinations, and psychoses as side effects, but with an incidence of less than 1 percent. When I contacted my friend Kevin Cahill, an expert in tropical medicine, he said that he would put the incidence of excessively vivid, colorful dreams closer to 30 percent-the full-blown hallucinations or psychoses were considerably rarer. I asked him how long the dreams would go on. A month or more, he said, because Lariam has a very long half-life and would take that long to be eliminated from the body. My nineteenth-century dreams gradually faded, though they took their time doing so.

Richard Howard, the poet, was thrown into a delirium for several days following back surgery. The day after the operation, lying in his hospital bed and looking up, he saw small animals all around the edges of the ceiling. They were the size of mice but had heads like those of deer; they were vivid: solid, animal-colored, with the movements of living creatures. "I knew they were real," he said, and he was astonished when his partner, arriving at the hospital, could not see them. This did not shake Richard's conviction; he was simply puzzled as to why his partner, an artist, could be so blind (after all, he was the one who was usually so good at seeing things). The thought that he might be hallucinating did not enter Richard's mind. He found the phenomenon remarkable ("I'm not accustomed to things like a frieze of deer heads on mouse bodies"), but he accepted them as real.

The next day, Richard, who teaches literature at a university, began seeing another remarkable sight, a "pageant of literature." The physicians, nurses, and hospital staff had dressed up as literary figures from the nineteenth century, and they were rehearsing the pageant. He was very impressed by the quality of their work, although he understood that some other observers were more critical. The "actors" talked freely among themselves, and with Richard. The pageant, he could see, took place on several floors of the hospital simultaneously; the floors seemed transparent to him, so that he could watch all the levels of the performance at once. The rehea.r.s.ers wanted his opinion, and he told them he thought it very attractively and intelligently done, delightful. Telling me this story six years later, he smiled, saying that even recollecting it was a delight. "It was a very privileged time," he said.

When real visitors came, the pageant would disappear, and Richard, alert and oriented, chatted with them in his usual way. But as soon as they left, the pageant recommenced. Richard is a man with an acute and critical mind, but his critical faculty, it seems, was in abeyance during his delirium, which lasted for three days, and was perhaps provoked by opiates or other drugs.

Richard is a great admirer of Henry James-and James, as it happens, also had a delirium, a terminal delirium, in December 1915, a.s.sociated with pneumonia and a high fever. Fred Kaplan describes it in his biography of James:

He had entered another imaginative world, one connected to the beginning of his life as a writer, to the Napoleonic world that had been a lifelong metaphor for the power of art, for the empire of his own creation. He began to dictate notes for a new novel, "fragments of the book he imagines himself to be writing." As if he were now writing a novel of which his own altered consciousness was the dramatic center, he dictated a vision of himself as Napoleon and his own family as the imperial Bonapartes.... William and Alice he grasped with his regent hand, addressing his "dear and most esteemed brother and sister." To them, to whom he had granted countries, he now gave the responsibility of supervising the detailed plans he had created for "the decoration of certain apartments, here of the Louvre and Tuileries, which you will find addressed in detail to artists and workmen who take them in hand." ... He was himself the "imperial eagle."

Taking down the dictation, Theodora [his secretary] felt it to be almost more than she could bear. "It is a heart-breaking thing to do, though, there is the extraordinary fact that his mind does retain the power to frame perfectly characteristic sentences."

This was recognized by others too-and it was said that though the master was raving, his style was "pure James" and, indeed, "late James."

Sometimes withdrawal from drugs or alcohol may cause a delirium dominated by hallucinatory voices and delusions-a delirium which is, in effect, a toxic psychosis, even though the person is not schizophrenic and has never had a psychosis before. Evelyn Waugh provided an extraordinary account of this in his autobiographical novel The Ordeal of Gilbert Pinfold.3 Waugh had been a very heavy drinker for years, and at some point in the 1950s he had added a potent sleeping draft (an elixir of chloral hydrate and bromide) to the alcohol. The draft grew stronger and stronger, as Waugh wrote of his alter ego, Gilbert Pinfold: "He was not scrupulous in measuring the dose. He splashed into the gla.s.s as much as his mood suggested and if he took too little and woke in the small hours he would get out of bed and make unsteadily for the bottle and a second swig."