IT WAS A TWO-HOUR TRIP from London. Reeve didn’t bother going out to Heathrow to retrieve his car. For one thing, it would have taken time; for another, Vincent wanted him to travel by public transport. Reeve had never heard of Tisbury. As his train pulled in, he saw beyond the station buildings a country town, a narrow main road snaking uphill, a soccer field turning to mud under the feet of the children playing there.

It had been raining stair rods the whole journey, but now the clouds were breaking up, showing chinks of early-evening light. Reeve wasn’t the only one getting off the train, and he studied his fellow travelers. They looked tired-Tisbury to London was a hell of a distance to commute-and had eyes only for the walk ahead, whether to parking lot or town house.

Joshua Vincent stood outside the station with his hands in his Barbour pockets. He was quick to spot Reeve; no one else looked like they didn’t know quite where to go.

Reeve had been expecting a farming type, tall and heavy-bodied with ruddy cheeks or maybe a sprouting beard to match the wild hair. But Vincent, though tall, was rake-thin, clean-shaven, and wore round, shining glasses. His fair hair was thinning badly; more scalp showing than follicles. He was pale and reticent and could have passed for a high-school science nerd. He was watching the commuters.

“Mr. Reeve?”

They shook hands. Vincent wanted them to wait there until all the commuters had left.

“Checking I wasn’t followed?” Reeve asked.

Vincent gave a thin smile. “Easy to spot a stranger at this railway station. They can’t help looking out of place. I’m so sorry to hear about Jim.” The tone of voice was genuine, not overwrought the way Giles Gulliver had been, and the more affecting for that. “How did it happen?”

They walked to the car while Reeve started his story. Through several tellings, he had learned to summarize, sticking to facts and not drawing conclusions. The car was a Subaru 4x4. Reeve had seen them around the farming towns in the West Highlands. He kept on talking as they drove, leaving Tisbury behind them. The countryside was a series of rises and dips with irregular wooded sections. They chased crows and magpies off the rough-finished road, then rolled over the flattened vermin which had attracted the birds in the first place.

Vincent didn’t interrupt the narrative once. And when Reeve had finished, they drove in silence until Reeve thought of a couple of things to add to his story.

As he was finishing, they turned off the road and started bumping along a mud track, churned up by farm machinery. Reeve could see the farm in front of them, a simple three-sided layout around a courtyard, with other buildings dotted about. It was very much like his own home.

Vincent stopped in the yard. A snapped command at a barking untethered sheepdog sent it padding back to its lair. A lone lamb bounded up to Reeve, bleating for food. He had the door open but hadn’t stepped out yet.

“I’d put your boots on before you do that,” Vincent warned him. So Reeve opened the bag he’d brought with him. Inside were all Jim’s notes plus a new pair of black Wellingtons, bought in the army surplus store near Finsbury Park Station. He kicked off his shoes and left them in the car, then pulled on the boots. He swiveled out of his seat and landed in a couple of inches of mud.

“Thanks for the tip,” he said, closing the door. “Is this your place?”

“No, I just stay here sometimes.” A young woman was peering at them through the kitchen window. Vincent waved at her, and she waved back. “Come on,” he said, “let’s catch a breath of air.”

In the long barn farthest from the house, two men were preparing to milk a couple of dozen cows, attaching clear plastic pumps to the teats. The cows’ udders were swollen and veinous, and complaints filled the shed. Vincent said hello to the men but did not introduce them. The milking machine shuddered as Reeve passed it. The two men paid him no attention at all.

On the other side of the milking shed, they came to a wall beyond which were darkening fields, trees silhouetted in the far distance.

“So?” Reeve asked. He was growing impatient.

Vincent turned to him. “I think people are trying to kill me, too.”

Then he told his story. “What do you know about BSE, Mr. Reeve?”

“Only what I’ve read in Jim’s notes.”

Vincent nodded. “Jim contacted me because he knew I’d expressed concern about OPs.”

“Organophosphorous materials?”

“That’s right. Have you heard of ME?”

“It’s a medical complaint.”

“There’s been a lot of controversy over it. Basically, some doctors have been skeptical that it exists, yet people keep coming down with the symptoms.” He shrugged. “The letters stand for myalgic encephalomyelitis.”

“I can see why it’s called ME. The E in BSE stands for something similar.”

“Encephalopathy. Encephalon just means the brain, from the Greek enkephalos, meaning ”within the head.“ I learned that a few years ago.” He stared out over the fields. “I’ve learned a lot these past few years.” He looked back at the farm. “This place is or-ganic. Do you know how BSE is supposed to have started?”

“I read something in Jim’s notes about animal feed.”

Vincent nodded. “MAFF-that’s the Ministry of Agriculture-relaxed their rules in the 1980s, allowing the rendering industry to take a few shortcuts. Don’t ask me why it happened or who was responsible, but it happened. They removed two processes, saving time and money. One was a solvent extraction, the other a steam-heat treatment. You see, the rendering industry was rendering down sheep and cows to feed to other cows. Bits of meat and bone were going into the feed cake.”

“Right.” Reeve buttoned up his jacket, still damp from a dash through the rain to catch the train. The evening was growing chilly.

“Because those two processes had been removed, prions got into the feed cake. Prion protein is sometimes called PrP.”

“I saw it in the notes, I think.”

“It causes scrapie in sheep.” Vincent raised a finger. “Remember, this is the accepted story I’m giving you. So the feed cake was infected, and the cows were being given the bovine form of sheep scrapie, which is BSE.” He paused, then smiled. “You’re wondering what all this has to do with Spanish cook-ing oil.”

Reeve nodded.

Vincent started to walk, following the wall along the back of the milking shed. “Well, the Spanish blamed contaminated cooking oil and left it at that. Only, some of the victims had never touched the oil.”

“And some of the cows who hadn’t eaten the infected feed still caught BSE?”

Vincent shook his head. “Oh, no, the point is this: some farms-organic farms-who had used the so-called infected feed didn’t catch the disease at all.”

“Hang on a second…”

“I know what you’re thinking. But organic farms are allowed to buy in twenty percent conventional feed.”

“So you’re saying BSE had nothing to do with feed cake, infected or otherwise?”

Vincent smiled without humor. “Why use the past tense? BSE is still with us. The ”infected‘ feed cake was banned on the eighteenth of July 1988.“ He pointed into the distance. ”I can show you calves less than six months old who have BSE. Vets from MAFF call them BABs: Born After the Ban. There’ve been more than ten thousand of them. To date, nearly a hundred and fifty thousand cows have died in the UK from BSE.“

They had come back to the farmyard. Vincent opened the Subaru. “Get in,” he said. Reeve got in. Vincent kept telling his story as he drove.

“I mentioned ME a little while back. When it first came to be noticed, it was supposed to have its roots in everyday stress. They called it Yuppie Flu. It isn’t called that nowadays. Now we call it Farmers’ Flu. That’s because so many farmers show symptoms. There’s a man-used to be a farmer, now he’s more of a campaigner, though he still tries to farm when they let him-who’s trying to discover why there’s an increase in the occurrence of neurological diseases like ME, Alzheimer’s, and Parkinson’s.”