The summer of 1965 was a sort of in-between time: I had completed my residency at U.C.L.A. and had left California, but I had three months ahead of me before taking up a research fellowship in New York. This should have been a time of delicious freedom, a wonderful and needed holiday after the sixty- and sometimes eighty-hour work weeks I had had at U.C.L.A. But I did not feel free. When I am not working, I get unmoored, have a sense of emptiness and structurelessness. Weekends were the danger times, the drug times, when I lived in California—and now an entire summer in my home town, London, stretched before me like a three-month-long weekend.

It was during this idle, mischievous time that I descended deeper into drug-taking, no longer confining it to weekends. I tried intravenous injection, which I had never done before. My parents, both physicians, were away, and, having the house to myself, I decided to explore the drug cabinet in their surgery, on the ground floor of our house, for something special to celebrate my thirty-second birthday. I had never taken morphine or any opiates before. I used a large syringe—why bother with piddling doses? And, after settling myself comfortably in bed, I drew up the contents of several vials, plunged the needle into a vein, and injected the morphine very slowly.

Within a minute or so, my attention was drawn to a sort of commotion on the sleeve of my dressing gown, which hung on the door. I gazed intently at this, and as I did so it resolved itself into a miniature but microscopically detailed battle scene. I could see silken tents of different colors, the largest of which was flying a royal pennant. There were gaily caparisoned horses, soldiers on horseback, their armor glinting in the sun, and men with longbows. I saw pipers with long silver pipes, raising these to their mouths, and then, very faintly, I heard their piping, too. I saw hundreds, thousands of men—two armies, two nations—preparing to do battle. I lost all sense of this being a spot on the sleeve of my dressing gown, or the fact that I was lying in bed, that I was in London, that it was 1965. Before shooting up the morphine, I had been reading Froissart’s “Chronicles” and “Henry V,” and now these became conflated in my hallucination. I realized that I was gazing at Agincourt, late in 1415, and looking down on the serried armies of England and France drawn up to do battle. And in the great pennanted tent, I knew, was Henry V himself. I had no sense that I was imagining or hallucinating any of this; what I saw was actual, real.

After a while, the scene started to fade, and I became dimly conscious, once more, that I was in London, stoned, hallucinating Agincourt on the sleeve of my dressing gown. It had been an enchanting and transporting experience, but now it was over. The drug effect was fading fast; Agincourt was hardly visible now. I glanced at my watch. I had injected the morphine at nine-thirty, and now it was ten. But I had a sense of something odd—it had been dusk when I took the morphine, it should now be darker still. But it was not. It was getting lighter, not darker, outside. It was ten, I now realized, but ten in the morning. I had been gazing, motionless, at my Agincourt for more than twelve hours. This shocked and sobered me, and made me see how one could spend entire days, nights, weeks, even years of one’s life in an opium stupor. I would make sure that my first opium experience was also my last.

At the end of that summer of 1965, I moved to New York to begin a postgraduate fellowship in neuropathology and neurochemistry. December, 1966, was a bad time: I was finding New York difficult to adjust to after my years in California; a love affair had gone sour; my research was going badly; and I was discovering that I was not cut out to be a bench scientist. Depressed and insomniac, I was taking ever-increasing doses of chloral hydrate to get to sleep, and was up to fifteen times the usual dose every night. And though I had managed to stockpile a huge amount of the drug—I raided the chemical supplies in the lab at work—this finally ran out on a bleak Tuesday a little before Christmas, and for the first time in several months I went to bed without my usual knockout dose. My sleep was poor, broken by nightmares and bizarre dreams, and upon waking I found myself excruciatingly sensitive to sounds. There were always trucks rumbling along the cobblestoned streets of the West Village; now it sounded as if they were crushing the cobblestones to powder as they passed.

Feeling a bit shaky, I did not ride my motorcycle to work, as usual, but took a train and a bus. Wednesday was brain-cutting day in the neuropathology department, and it was my turn to cut the brain into neat horizontal slices, to identify the main structures as I did so, and observe whether there were any departures from normal. I was usually pretty good at this, but today I found my hand trembling visibly, embarrassingly, and the anatomical names were slow in coming to mind.

When the session ended, I went across the road, as I often did, for a cup of coffee and a sandwich. As I was stirring the coffee, it suddenly turned green, then purple. I looked up, startled, and saw that a customer paying his bill at the cash register had a huge proboscidean head, like an elephant seal. Panic seized me; I slammed a five-dollar bill on the table and ran across the road to a bus. But all the passengers on the bus seemed to have smooth white heads like giant eggs, with huge glittering eyes like the faceted compound eyes of insects—their eyes seemed to move in sudden jerks, which increased the feeling of their fearsomeness and alienness. I realized that I was hallucinating or experiencing some bizarre perceptual disorder, that I could not stop what was happening in my brain, and that I had to maintain at least an external control and not panic or scream or become catatonic, faced by the bug-eyed monsters around me. The best way of doing this, I found, was to write, to describe the hallucination in clear, almost clinical detail, and, in so doing, become an observer, even an explorer, not a helpless victim, of the craziness inside me. I am never without pen and notebook, and now I wrote for dear life, as wave after wave of hallucination rolled over me.

Description, writing, had always been my best way of dealing with complex or frightening situations—though it had never been tested in so terrifying a situation. But it worked; by describing in my lab notebook what was going on, I managed to maintain a semblance of control, though the hallucinations continued, mutating all the while.

Somehow I got off at the right bus stop and onto the train, even though everything now was in motion, whirling vertiginously, tilting and even turning upside down. And I managed to get off at the right station, in my neighborhood in Greenwich Village. As I emerged from the subway, the buildings around me were tossing and flapping from side to side, like flags blowing in a high wind. I was enormously relieved to make it back to my apartment without being attacked, or arrested, or killed by the rushing traffic on the way. As soon as I got back, I felt I had to contact somebody—someone who knew me well, who was both a doctor and a friend. The pediatrician Carol Burnett was the person: we had interned together in San Francisco five years earlier, and resumed a close friendship now that we were both in New York. Carol would understand, she would know what to do. I dialled her number with a now grossly tremulous hand. “Carol,” I said, as soon as she picked up, “I want to say goodbye. I’ve gone mad, psychotic, insane. It started this morning and it’s getting worse all the while.”