He was doing that the night he had his unpleasant experience. The ward was one where they kept babies and young children so badly deformed they were sure to die outside hospital, and not last much longer even inside. We got a letter explaining most of what had happened from a nurse who had been friendly with my brother, and from the tone of her letter she thought it was wrong to keep some of the children alive; apparently, they were little else than exhibits to be shown to students by the doctors and consultants.

It was a hot, close night in July, and Eric was down in this ghoulish place, near the hospital boiler room and store rooms.

He'd had a sore head all day, and while he was in the ward it had worsened into a bad migraine. The ventilation in the place had been faulty for the past couple of weeks, and engineers had been working on the system; that night it was hot and stuffy, and Eric's migraines have always been bad in those conditions. Somebody was coming to replace him in an hour or so, or I suppose even Eric would have admitted defeat and left to go back to his hall of residence and lie down. As it was, he was going round the ward changing nappies and quieting mewling babies and changing dressings and drips or whatever, his head feeling as though it was splitting and his vision distorted with lights and lines.

The child he was attending to when it happened was more or less a vegetable. Amongst its other defects it was totally incontinent, unable to make any other noise apart from a gurgle, couldn't control its muscles properly — even its head had to be supported by a brace — and it wore a metal plate over its head because the bones which should have made up its skull never did grow together, and even the skin over its brain was paper thin.

It had to be fed every few hours with some special mixture, and Eric was doing that when it happened. He had noticed that the child was a little quieter than usual, just sitting there slackly in its chair and staring straight ahead, breathing lightly, eyes glazed and an almost peaceful expression on its usually vacant face. It seemed to be incapable of taking its food, though — one of the few activities that normally it was able to appreciate and even join in. Eric was patient, and held the spoon in front of its unfocused eyes; he put it to its lips where normally the child would have put its tongue out, or try to lean forward and take the spoon into its mouth, but that night it just sat there, not gurgling, not shaking its head or shifting or flapping its arms or rolling its eyes but staring and staring, that curious look on its face which might have been mistaken for happiness.

Eric persevered, sitting closer, trying to ignore the pressing pain in his own head as the migraine got gradually worse. He spoke gently to the child — something that would normally get it to swivel its eyes and shift its head towards the source of the noise, but which that night had no effect at all. Eric checked the sheet of paper by the chair to see if the child had been given any extra medication, but everything appeared normal. He edged closer, crooning, waving the spoon, fighting the waves of pain inside his skull.

Then he saw something, something like a movement, just a tiny little movement, barely visible on the shaved head of the slightly smiling child. Whatever it was was small and slow.

Eric blinked, shook his head to try to dislodge the quivering lights of the migraine building inside. He stood up, still holding the spoon with the mushy food on it. He bent closer to the skull of the child, looking closer. He couldn't see anything, but he looked round the edge of the metal skull-cap the child wore, thought he saw something under it, and lifted it easily from the head of the infant to see if there was anything wrong.

A boiler-room worker heard Eric screaming and rushed into the ward brandishing a big spanner; he found Eric crammed into a corner howling as hard as he could at the floor, his head down between his knees as he half-knelt, half-lay, foetal on the tiles. The chair the child was in had been tipped over, and it and the strapped-in child, who was still smiling, lay on the floor a few yards away.

The man from the boiler-room shook Eric but got no response. Then he looked at the child on the chair and went over to it, perhaps to right its chair; he got within a couple of feet, then rushed to the door, throwing up before he got there.

A ward sister from the floor above found the man in the corridor still fighting his dry heaves when she came down to see what all the fuss was about. Eric had stopped screaming by that time and gone quiet. The child was still smiling.

The sister righted the child's chair. Whether she choked back any of her own sickness, or felt dizzy, or whether she had seen as bad or worse before and treated it as just something to be coped with, I don't know, but she finally pulled things together, calling for help on the telephone and getting Eric stiffly out of his corner. She put him in a seat, covered the child's head with a towel, and comforted the workman. She had removed the spoon from the open skull of the smiling infant. Eric had stuck it there, perhaps thinking in that first instant of his mania to spoon out what he saw.

Flies had got into the ward, presumably when the air-conditioning had been faulty earlier. They had got underneath the stainless steel of the child's skull-cap and deposited their eggs there. What Eric saw when he lifted that plate up, what he saw with all that weight of human suffering above, with all that mighty spread of closed-in, heat-struck darkened city all around, what he saw with his own skull splitting, was a slowly writhing nest of fat maggots, swimming in their combined digestive juices as they consumed the brain of the child.

In fact, Eric appeared to recover from what happened. He was sedated, he spent a couple of nights in the hospital as a patient, then a few days resting in his room in the residence. He went back to his studies within the week, and attended classes as normal. A few people knew something had happened, and they saw that Eric was quieter, but that was all. My father and I didn't know anything except that he'd been off from his classes for a short while because of a migraine.

Later we heard Eric started drinking a lot, missing classes, turning up at the wrong ones, shouting in his sleep and waking other people on his floor of the residence, taking drugs, missing exams and practical classes…. In the end the University had to suggest he took the rest of the year off because he had missed so much work. Eric took it badly; he got all his books and piled them up in the corridor outside his tutor's room and set light to them. He was lucky they didn't prosecute him, but the University authorities took a lenient view of the smoke and the slight damage to their ancient wood panelling, and Eric came back to the island.

But not to me. He refused to have anything to do with me, and kept himself locked in his room, listening to his records very loudly and hardly ever going out except to the town, where he was quickly banned from all four pubs for starting fights and shouting and swearing at people. When he did notice me he would stare at me with his huge eyes, or tap his nose and wink slyly. His eyes had grown dark-set and were underlined by bags, and his nose seemed to twitch a lot, too. Once he picked me up and gave me a kiss on the lips which really made me frightened.

My father grew almost as uncommunicative as Eric. He settled into a morose existence of long walks and dour, introspective silences. He started smoking cigarettes, virtually chain-smoking for a while. For a month or so the house was hell to be in, and I went out a lot, or stayed in my room and watched television.

Then Eric took to frightening small boys from the town, first by throwing worms at them, then by stuffing worms down their shirts as they came back from school. Some of the parents, a teacher and Diggs came to the island to see my father once Eric started trying to force the kids to eat the worms and handfuls of maggots. I sat sweating in my room while they met in the lounge underneath, the parents shouting at my father. Eric was talked to by the doctor, by Diggs, even by a social worker from Inverness, but he didn't say much; he just sat smiling and sometimes mentioned how much protein there was in worms. Once he came back to the house all battered and bleeding, and my father and I assumed some of the bigger boys or a few of the parents had caught him and beaten him.