This novel by a doctor is actually an encyclopaedia of impossible illnesses that people suffer from

Amnesia inversa

The invalid with Amnesia inversa explains away the first memory lapses because they involve distant acquaintances: barbers and peddlers, inn-keepers and tobacconists. But then the episodes become more frequent.

Gatekeepers who once greeted the invalid by name now ask pointed questions about his purpose. Vendors from whom he purchased flour and salt each week claim to never have seen his face before. His neighbours’ eyes no longer flicker with recognition at the sight of him, and his friends answer their doors with the polite, suspicious smiles one reserves for strangers.

The sufferer tries amulets and tinctures, prayers and supplications, but the disease progresses, swallowing all those dear to him until, finally, he awakens on the rumpled sheets of a baffled and affronted lover, and realizes that he has been wiped from all human memory.

Scattered across the shelves of the Central Library are reports written by physicians who, grasping the nature of the condition, transcribed the words of the invalids while they spoke and dispatched the manuscripts with all possible haste before their own memories could fade. These physicians, when questioned about the reports, identified the handwriting as their own but had no memory of having written them. Perhaps that is evidence enough for the existence of this disease.

The fate of invalids with Amnesia inversa remains unknown, for the very nature of the malady prevents them from being studied. There are at least three possibilities. Perhaps the invalids live at home in anonymity, strangers even to neighbours who see them every day of their lives. Or they take their own lives in despair, hoping that death will end the amnesia and allow their friends to mourn them. Or else they transform themselves into wanderers, filling their days with fleeting infatuations and camaraderies in towns that they leave under cover of night, ridding themselves of the need to be remembered.

Agricola’s Disease

Agricola’s Disease robs its victims of their hearing; within two years of its onset, they become profoundly deaf. There is at first little to distinguish Agricola’s from other afflictions that deaden the ear, but once the disease has advanced, an infallible test can separate it from the rest. Responsible physicians perform this test only on wealthy invalids, because a diagnosis of Agricola’s Disease can drive its victims to penury.

The test is simple. The only elixir known to treat Agricola’s Disease comes from alchemists in the East, who must swear on pain of death to safeguard the ancient recipe. Many otologists keep a minute quantity of this elixir in their safes, a dilution of one part to sixty thousand.

To test for the disease, they place a single drop on the invalid’s tongue. Most invalids hear nothing, but those with Agricola’s Disease hear a whisper of sound, a soft breeze, that ebbs almost before it begins. The diagnosis is made.

The elixir is worth more by weight than any other substance on earth. Once a year, small phials of the green liquid leave the Imperial Apothecary and cross the oceans in armed ships. When a ship reaches port, news of its arrival flies through the land. Merchants set up tents on the shore, and invalids of high birth arrive with pouches of gold, ready for the auction to begin.

When the Imperial auctioneer holds up his commodity, the invalids stack their bids on their tables. Within a few moments the auction ends, and the phials go to those with the biggest piles of gold. They pour the contents into their mouths and the world bursts open. The grumbling of thwarted merchants, the clinking of coins behind the auctioneer’s desk, the cawing of gulls on the sand, the cries of fishwives hawking their catch, and the roar of the churning, frothing sea soak into their bones. The invalids fall to their knees, weeping.

And then the cure begins to fade. They plead for mercy, but Agricola’s Disease drops them back into their oubliette.

Since the day an outraged god loosed the first afflictions on the earth, people with deafness have adapted to their state. But those with Agricola’s Disease, once they taste the elixir, can never do so. They gamble away their lands and fortunes to drink it again. Desire for sound consumes them until the remedy becomes as much a part of their misfortune as the malady itself.

Many of our own alchemists have tried to distil this elixir. The recipe remains elusive, but we are learning some of its properties. It appears to contain an almost endless number of vital essences, mixed in proportions that correspond to the full range of human hearing. At the latest tally, over three thousand of these have been identified – some that restore the invalid’s ability to hear the wings of sparrows, others that cover the lower sonorities of dulcimers, yet others that are concerned with the sounds of raindrops.

Buried deep within the concoction are the more complex essences governing speech. Some open the ears to the voices of priests, some to those of barbers, some to the words of madmen.

Immortalitas diabolica

Immortalitas diabolica is poorly documented, for no one will admit to suffering from it. The authorities become suspicious, however, when villages whisper of an inhabitant with obscene youthfulness, free of the illnesses and deformities that have visited everyone else his age.

Immortalitas diabolica grants its victims the ability to will away every pain and infirmity that befalls them. The ability first surfaces in childhood, when the instantaneous cure of scrapes and fevers seems as natural to them as speaking. As they grow, they see those around them suffer through illnesses that they themselves can dispel with a fleeting thought.

They acquire a reputation for remarkable health, but it is not until the fourth and fifth decades of their lives that people around them question their pristine skin, their robust teeth, their luminous hair. It is usually then that the invalid learns the terrible truth about his health.

Immortalitas diabolica does not cure afflictions – it transfers them to the bodies of others. When a person with this power reaches within himself to expunge his illness, its vapours leave his body and settle on some innocent passer-by, who must now suffer an illness fate did not ordain for him. As the person with Immortalitas diabolica ages, the legacy of the gift weighs heavier upon him, and while he can effortlessly banish diseases that threaten his body, he cannot banish the memories of those whose lives he has blighted.

Some people with Immortalitas diabolica try to reject the gift, allowing wrinkles to line their faces, scars to riddle their lungs, cancers to flourish in their guts. But when the terminal moments of agony and suffocation arrive, Lucifer rages in their minds.

Intoxicated with pain, they stagger then into dingy alleys, to the huts of the poor and destitute who are unlikely to be missed, and they allow themselves to drink from the monstrous elixir that swirls within. When the deed is done, their young, muscular legs whisk them away as cries emerge from the windows beside which they stood.

Nevertheless, those cursed with Immortalitas diabolica are not truly immortal. After extraordinarily long lives, they die of causes unknown. Necropsy reveals youthful, supple tissues, a body that appears to have expired at the peak of health. Spasms of the heart, poisons in the blood, or other fatal chances too sudden to be wished away may lie behind these deaths, but some authorities suggest that the mechanism may not be so simple.

They argue that sickness and suffering are integral to the human soul, so a person with Immortalitas diabolica must forsake fragments of his soul each time he expunges an illness. It is then only a matter of time before the soul is ground to dust, and all that remains is a body in pristine repair, devoid of any vital force to sustain it.

Excerpted with permission from The Afflictions, Vikram Paralkar, HarperCollins India.