My sickness felt dark, though in truth it was more akin to light. Darkness is the absence of something, light an invading presence, much like the unwelcome attentions of an inimical virus or bacteria.

It clouded my judgement with charcoal-grey mists of pain, rolling haphazardly across my days so that I could never predetermine when the discomfort would strike. At times, when the pain was a dull memory (for who can truly remember the details of agony?), I would ponder on whether or not I was deceiving myself. True, my sudden hair loss and loose skin were undeniable signs, but there was also the fear in my mind that the power of will was making me ill. Before he left me, my husband told me that I was imagining things. I still carry the scars of that comment.

Then the pain came, again and again, and doubt vanished. The doctors rarely helped: "Have some Anadin and take a week off work," one of them had said, eyes glinting from a three drink lunch. I had taken his advice - naturally, he was a doctor - and cried out when it did not work. The sense of betrayal was vast.

"I'll send you to a specialist," another said, encouraging me with her forthright honesty. "You need to see a specialist. I'll send you."

The specialist was tall, graceful, bored. I wanted to scream that he held my future in his hands. "Take some pain killers, I'll take some X-rays," he said, and then he ignored the shadows. Perhaps, in a way, these doctors know that light is the nearest to illness, and when their examinations are smudged by dark, they think all is well. Maybe they were simply incompetent.

So, I came here.

The waiting room is dark. Wallpaper is slipping from the walls like skin fleeing dead flesh. The light is a naked bulb, no more. Around this there flutters a moth, spitting and spiralling every time it encounters the heat destined to kill it. I go to help. But then I see the inevitability of things, how the dumb creature will simply find another light to fling itself against, until it floats to the ground as a cinder.

Am I the same as this moth? Am I throwing myself at false hopes?

The doctor comes highly recommended by junkies and criminals, and those afflicted with the modern curses of gunshot wounds and skin slit by surreptitious knives in dark alleys. He's a healer for the night, possibly dangerous, probably unqualified or, even worse, struck off for some terrible misdemeanour. My illness has reduced me to this, covert expeditions in the early hours. I feel that he is my final hope. I begin to shiver. It is not through fear - nothing is frightening when you are staring death in the face - but a new bout of pain. Its white-hot waves roar through me, and every seventh spasm is an agony shoving me closer towards unconsciousness. Memory is inadequate at describing many things; some are best remembered by being relived. And this was the terrible way in which my own body recalls the throes of my slow, inevitable rot.

"Miss West?" The door across from me has opened, showing a small man with grey hair and a complexion to complement this. The room beyond exudes a warm aroma of cooking things, but I wonder whether this is simply because fresh air is cleaning the putrid atmosphere hanging around me. My wounds drip and rot. I leak.

"Yes." "You're in pain." It is a statement of fact, containing not a hint of pity or interest. He temples his hands beneath his chin, tapping his index fingers together. I feel that I am being viewed, not looked at.

"I've been in pain for years. I can't tell you how much." I almost hiss the words as pain washes over me again, sparkling my nerve-ends into fiery brands.

"How much do you have?" I am ready for the question. Even so, I find it shocking. "Two thousand."

He nods, expression hiding his thoughts. I don't care if I am paying him too much. I just want it to go away.

"I practise natural remedies here, Miss West," the doctor says. "I don't expect you to be happy with what I ask you to do. Neither should you anticipate anything pleasant coming from this meeting. At least, not for several days."

"Can you help me?" He smiles, holds his chin thoughtfully. It is almost as if he is prevaricating through a perverted sense of sadism. "Yes, I can. I will. As I said, I practise Teng B'Han. Which, if you know your medicines, is the medicine of the body, and bodies. It involves a certain_unpleasantness."

With that he moves back into his room. Light fills the doorway and blinds me with its unclean glare.

"The scorpion is a much maligned creature," the doctor says, dropping the scrabbling animal into a glass case. It hits the metal plate below, scurries around its new prison and flexes its tail. "As well as being extremely useful in my art, they are also exceptional gymnasts. Sad" He slides a glass lid over the case and clips it shut. There are beads of sweat on his upper lip. The room is cold.

He reaches down and twists a knob on the pedestal holding the glass case. There is a hiss of gas, the click of a button. Blue flames erupt. The scorpion leaps, flips, scratches at the glass. It lands amongst the flames and then, already blackening and crinkling, jumps again. It almost strikes the roof of the box before falling down onto the glowing metal plate, where it shrivels and crackles its last.

"You know that animals are dying for you today, Miss West?" His voice is slow and serious, like a teacher talking to an impressionable pupil.

I shake my head. I cannot shift my gaze. The flames die down, leaving the charred remains of the scorpion as the only clue to their existence. Its legs point skyward. It reminds me of the moulded residents of Pompeii, still warding off the clouds of stinging ash centuries after it has been cleared away.

"For your particular range of afflictions, we have to flood you with the dark. This combats the burning blight within your body and will, at some point in the near future, eradicate it." He has small eyes, black pearls amid the oyster-white sallowness of his face. His lips are powdered with dried spittle. His flesh looks dead, and I wonder what he has been feeding himself.

"Next, a friendly frog to draw out the sourness. Kiss the prince." He smiles, but the expression is patently false. He does not like what he's doing any more than I do. I wonder at my reasons for coming here, consider the possibility that, perhaps, my other doctors had been right. Maybe my imagination has carried me away to unknown planes of grief and suffering, all the while laughing at my foolishness. But a spike of angry pain drives between my ribs, squeezing a gasp and pinning me to the tatty chair.

He drops the frog into the case and replaces the lid. It jumps several times - evidently the metal is still hot - until it chances to land on the sad remains of the scorpion. Here it stands, ribbitting like the champion in some grotesque boxing match, until the doctor fires up the gas.

The creature does not shrivel and turn black, like the scorpion. It explodes. Its innards emerge from the flames and splash across the glass, instantly spitting and steaming as the heat reaches them, solidifying.

"Oh God," I say, but I cannot turn away. I raise wasted hands to my face, the stain of month old polish spotting my nails. The fascination dilutes the discomfort. "Is it working?" I ask, wondering what the hell Teng B'Han is. Perhaps it is the dismissal of pain by the concentration of the mind on other aspects of life? The death of others?

"Of course not," he says, "you have yet to drink the potion." Agony drowns my disbelief.

Other creatures follow the scorpion and frog. Between each, a cursory examination from the doctor. When he sees the wrinkled skin of my hands, he guides a slow-worm into the tank. For my receding gums, a sparrow with an injured wing gives a momentary show of flight before the flames consume it. He inserts a finger into my anus, frowns, and drops a startled tortoise into the steadily filling box. The creature withdraws into its shell, then bursts out again as the heat wraps it in blue flames. Its insides bubble on the glass alongside those of the frog.

I am retching. The fluid, still hot, has dribbled down my gullet and is searing its way into my veins. I cannot relate the taste; imagine drinking shit and blood and sperm and mucous, heated, stirred. A series of spasms wrench my guts as I try to reject what I have just imbibed, but somehow my stomach lining realises the worth in this foul syrup. I keep it down. It churns, like a bad breakfast.

The doctor is a nasty little man. He smiles encouragingly when I drink, and for a moment I think that he was enjoying the discomfort he could administer. But there is something else in his expression, a purity of purpose that makes me think he is not the charlatan I had first suspected him of being. And what he does with the remains of the animals - how he separates the fused mess of flesh and bone and shell - is art itself.

He creates, this doctor. A creepy little demi-god, he moulds the mingled clay of the dead creatures in his hands, twisting soft bones this way, snapping weakened shells that. The legs of the scorpion, twisted in to point at themselves, form the knobbly joint of limbs. The shell of the tortoise, cracked but still whole, is the head, eye-holes knocked out and filled with the moulded remains of innards from the inside surface of the glass. Eyes that cannot see stare at me from the doctor's table. The man hums as he works, perhaps considering the money, or possibly merely revelling in the art which marks him as much more than just a doctor.

"Is this safe?" I ask.

He looks at me sourly. "Is anything in life safe?"

It is not an answer I like - years ago, I would have taken umbrage and entered into all manner of arguments with him. But now, surviving in pain and warding off death with little more than stubborn determination, I tend to agree.

When he gives me what he has made, I hand over the payment. He tells me to keep it with me for several weeks, until the pain has gone and the dark has defeated the burning agony of my illness. At first I draw back, disgusted and awed by what he offers. But then the curious confidence shows itself on his face again, and I think that maybe he's right. He knows what he is doing. He may yet help.

The thing is the size of a baby, charred brown, arms and legs moulded from the brittle bones of dead animals. Molten flesh dresses its skeleton, and the stringy remnants of intestines give it a full head of hair. Inside, there is a mish-mash of body parts, a truly inter-species bonding of fire.

It is still warm. "Can I see you again, if-" I begin, but he cuts me off.

"Don't come back," he says. He ushers me out and shuts the door, leaving me alone with the dark. I still feel sick, but my body denies me the relief my mind craves so much. The potion sits in my stomach, smug, heavy.

As I walk it swills about, reminding me of all the parts which went to make it. There is a sudden pain in my guts, as if the scorpion has waited until now to sting me.

In my arms, I carry the mannequin he has made for me. It looks up with fluid eyes.

His house is as clandestine as the doctor himself. The only way out is via an alley, long and dark and dribbling slime from its walls at innocent passers-by. The moon sheds a weak borrowed light onto the scene, and I see a family of rats feasting on the remains of a ginger cat. They glare up at me, then resume their feeding. Unafraid, unthreatening. I splash through puddles, the stench of piss and death rising from the disturbed liquids and invading my nostrils with acid fingers. The shape in my arms is still warm. Sometimes, I think I can still hear the final shrieking and sizzling of the animals as they burn.

On the street, I feel exposed. I am tired now, the illness robbing me of precious energy as I make my way home. It has begun to rain. I wonder what the mannequin is for. The pain has receded for now, and in my stomach the warmth of the potion feels almost comfortable. My whole body is heavy, dark, as though my flesh swallows light, and colours and textures are keeping themselves well hidden from the probing fingers of the illness.

How I hope that this is the case.

I reach my house just as the sun begins to cast its gaze across the town.

Darkness flees, mostly. But inside I draw the curtains and lay back on my bed. The doll is at my side, still warm. Sometimes, when it is close to my chest and I hold it pressed to the racing beat of my heart, I can feel it move.

Sleep takes me. Dreams unfold, and over the days they mesh with reality to form a fragmented flood of images and sensory input. I feel something pricking at me with sharp points, and when I open my eyes the doll appears to be clambering over my naked form. When it reaches the area of maximum pain, it pierces my skin with its bone-claws and my body turns numb. Its legs work constantly, a wind-up toy possessed of perpetual motion. I smell burning, the acidic reek of internal gases exploding into flowering flame.

The hairs in my nostrils shrivel to dead seeds in the heat. Sometimes when I wake my mouth is open, and my tongue is huge and swollen and coated with the thick sliminess of the doctor's potion. Blood trickles down my throat, but it does not taste like my own.

Several times I half-wake to find the doll form clasping itself to my leg, its limbs wrapped in chitinous homage. As time progresses the doll moves further and further up; to my knee, my thigh, the junction of my legs. It is as though it's progressing closer and closer to the dark heart of me from whence, perhaps, it wishes it had come.

I burn a fever, but I am glad, because it goes some way to covering the heat radiating from the form's dead parts. Once I open my eyes to find the thing above me, resting on my face, staring at me drippingly. I scream back into a dream, where sense and language are mutated into bastardised forms of themselves. I smell the heat from the doll; I hear its anger; I see the sour fluid leaking from its poorly formed orifices.

Eventually, when night and day have swapped several times, I sit up.

A mind unclouded by pain becomes inquisitive. I am cured. The terrible pains have gone, and although my body is weaker and thinner than ever, I can sense no sign of the illness abiding within me. The blaze of my affliction has darkened. I want to know how.

I need to find the doctor. From where is he procuring his exotic animals? In which strange book did he learn of the wonders he can perform? Why is he practising in the sewers and doldrums of the city, instead of at its medicinal helm? In my newly purged mind, I envisage him as a saint amongst the na‹ve, dishing out his wisdom in the form of hot potions and lucky charms, taking money merely to survive, not to profit. A sort of Robin Hood of the ill. Yet more elusive.

When I leave the house, I take the doll with me - heavier, now, bearing my own pain and sickness in silent acquiescence. It is beginning to rot, shedding wet scales of flesh and leaving foul traces of itself on my clothes. But the doctor told me to carry it for several weeks, and I am loath to disobey his command. He is, after all, the doctor of the dark.

I find the alley easily enough. In daylight it is grotty and squalid, not frightening. I pass the chewed remains of an old ginger tom, its pelt grey now, tail stuck to a weeping brick wall with its own gore. The path twists and turns, the guts of the city, and eventually disgorges me back onto the pavement next to a main road. I am unfulfilled. I am sure I did not pass the doctor's house.

I try again, and emerge elsewhere. Again, and this time, as I step out next to the town's war memorial, the sun has already made haste for sleep. Darkness spills out from old shop doorways, closely followed by those who covet its camouflage. I turn and head for home, hugging the wet doll to me, ignorant now of the stench emanating from it. I tell myself that I will not stop trying to find the doctor; to thank him, praise him, encourage him to bring his strange medicine to the masses. Surely, there would be disgust at first, scorn, even cries of blasphemy and heretic. But it has worked, and I am living, breathing proof of that.

I fear the doctor has gone for good.

The doll is wasting, melting back into its previous formlessness. Its smell has changed to one of age, rather than rot. I should have disposed of it by now. Sometimes, at night, I feel heat leaking from the pitiful shape next to me in my bed. When morning comes it is cool again, because nothing lives forever.

But perhaps it should. Maybe I will not discard it, this child of mine, this product of all my ills. For then, what would I have gained for all my pain? Health, surely, but I had that long before. If I lose this convergence of all my sickness, then nothing would have come from something. I cannot allow that to happen.

Already, it feels lighter. And my hands are beginning to shake once more.