There were two dead pigs dangling from the ceiling, spinning around together in a slow pirouette. Another was submerged in a vat of scalding water, and one more lay sprawled on the grate of a heavy iron rack. Kurt had been working since ten to six. There was a lot to do getting the slaughterhouse going in the morning. The boiler had to be fired, the knives sharpened – and lots more. The boss would be in by eight to start gutting, and would want things set to go. He glanced at his two guests standing awkwardly in the shadows. “Geeks,” he muttered under his breath.

“Ready?” Kurt asked. The girl, dressed in faded jeans, a white lab coat, and old Nike running shoes, nodded and held a bucket under the chin of one of the twirling bodies. Kurt stroked his hip with the palm of his hand and produced a thin metal blade from the knife scabbard he wore. The knife flashed silver and then disappeared. Blood, dark and gurgling, poured out into the bucket with a sudden spurt. A pink froth rose around the rim as the girl lugged the now heavy bucket a few steps to the 5-gallon bottle. It was made of heavy green-blue glass, a true water bottle from the days before plastic made glass obsolete. A man was holding a funnel in the mouth of the bottle, steadying it for her to pour. The blood gurgled and foamed some more as it flooded down the insides of the glass. The man, dressed as she was, straightened and said, “ I think we ought to put another 80 cc of buffer in the next time. I mean, we’ve got it – might as well use it.” They washed out the funnel and the bucket in the sink while he struggled to get the water temperature right. There were no handles for running the faucet. Instead, there were two metal pedals under the sink – one for hot and one for cold. The pedals were awfully close together and his feet couldn’t seem to distinguish one from the other, so the water see-sawed from steaming to ice cold and back again. They jerked their hands in and out of the stream each time it happened, exchanging startled expressions. When all the glassware was clean and ready, they waited.

There was a Red Devil kerosene space heater glowing orange next to the wall. They shuffled around it, holding up their cold feet and melting the rubber on the tips of their sneakers as they waited for the next set of pigs. A sharp crack made them both jump as Kurt shot the fifth pig of the day between the eyes. She took a small step toward the pen to watch. He measured out an extra dose of buffer from the brown glass container, added it to the bucket, then leaned back against the wall, studying her. Her hair was pulled back from her face and pinned neatly behind her head. A few stray wisps fell in front of her ear. It was red, but a very dark red. In the dim, misty light of the slaughterhouse it seemed dark brown, but it would shimmer with copper when they stepped outside into the bright January sunlight. She was small, and he noticed how tiny her white feet seemed as she stood next to Kurt in his big black rubber boots. Freckles were scattered from her forehead to her chin, thickest over her cheeks and her nose, but he got the impression that they didn’t stop at any particular place and probably continued down past her shirt collar in all directions. Her eyes were wide and pretty, but the color was hard to describe. Sometimes they seemed very green, but with a change of mood or light they might turn slate gray or even look dark and brownish. He liked them, but he found himself staring at them from time to time, trying to settle in his mind what color they really were. He scowled at himself and turned to stare at the heater, realizing that he’d been studying her.

He tried not to say anything much to her for the rest of the morning. The pigs came to them in pairs every fifteen minutes, and they worked steadily until the five gallon bottle was full and foam poured out the top and ran down the side. As he was wiping it clean, she came to him carrying a heart that had been severed from its great vessels and flung into a barrel. It was in V-fib, shivering as if from the unaccustomed cold outside a living body. He ran warm water into it from the sink, and showed her where the valves were and how they controlled the flow of liquid. Suddenly there were four or five strong, coordinated beats as the heart shuddered back into a normal rhythm. Bloody water squirted out onto the wall. Then the heart went limp in his hands, and he turned to her in mock grief, saying, “I’m afraid that I have some terrible news.” She laughed and said, “Doctor, I think you’d have better luck if there was more of the patient left.” He smiled at her and felt his own heart suddenly racing.

The massive container of blood made them waddle like ducks as they staggered together through the door. But in all that gore there was only an ounce or two of the stuff they were seeking – the leukocytes. Pig leukocytes (white blood cells) contain an enzyme called 12-LOX, which is essentially the same as the 12-LOX enzyme in humans. Prostate cancers that grow increasingly invasive also seem to make a lot more 12-LOX than what might be considered normal. It was his interest in this enzyme that brought the two of them to the slaughterhouse. Over the few months of her internship, the girl became rather good at isolating 12-LOX from pig leukocytes. It would not be until some years and many pig blood failures later that he would truly appreciate her talent in this area. A pig blood prep takes at least 6 more hours after collecting the blood. Red blood cells are full of iron, so they are a bit heavier than the white cells. When you spin them in a centrifuge, they end up concentrated near the bottom while the white cells float toward the top. So they spun them, and then skimmed off the layer rich in leukocytes from the top. All cells have about the same amount of salt in them as sea water, so if you pour salt-less distilled water onto them, that water seeps across their membranes and causes them to swell up like a balloon and pop. The white cells resist this by pumping the excess water back out, so the red cells are the first to pop when stressed in this way. They alternately centrifuged and exploded the cells to get rid of all but the leukocytes. Over the course of the afternoon, the five gallons of blood was reduced to perhaps 3 tablespoons of pure white cells, looking something like wet baby’s oatmeal. When she brought it to him her face was bright and proud. Their eyes met in a brief exchange as they rolled the gelatinous mass into the ultrasonicator. She knew how pleased he was. The duet they were playing together was simple and beautiful, with competence and knowledge intertwined like fingers holding hands.

On Saturday morning she would follow him on his rounds at the hospital. His patients were old and dying, withering away, their tissues bathed from within by the malevolent secretions of their tumors. They looked forward to her visits more eagerly than his, because she brought only a fresh and compassionate face, some tender teasing, and no needles or devastating laboratory numbers. He could see a faint spark in their tired eyes. Reproduction was now out of the question for them – but some of the equipment needed for sex resides in the brain. Those parts were still working, and it was touching to see how happy it made them to have that mechanism stirred into wakefulness by the figure of a young girl.

He thought for a moment about the millions of dollars and countless hours being spent in pursuit of 12-LOX, an inscrutable little molecule whose allegiance in this battle was not even known. 12-LOX had a voracious appetite for polyunsaturates – the things that butter companies were so bursting with pride about. Polyunstaurates are just fats, and 12-LOX pulled them out of the membranes around it and burned them. Dozens of times each second, 12-LOX reached out its microscopic arms, plucked an unsaturated fat from the folds of the cell wall and slid the hapless molecule across the iron atom at the 12-LOX reactive core. Electrons flew like sparks from a flint, impaling the fatty acid with a molecule of oxygen. The resulting new compounds had such long names that no one ever wrote them. Five or six capital letters gave a name and muted the strangeness of something not at all well understood. If a person ate a lot of fish and their omega-3 fats, 12-LOX would ignite them and make something called 12-HpEPE. She wrinkled her nose and grinned the first time he said it, because it was pronounced “H-Pee-Pee.” 12-HpEPE made the leukocytes of his prostate cancer patients agitated and enraged. Sometimes. It was difficult to harvest the leukocytes of cancer patients, because his team was not permitted the same liberties with them that they took with the pigs. The blood samples were small, and the isolations irreproducible. On a few occasions, he had seen the leukocytes respond to the 12-HpEPE with a focused, lethal assault on the tumor cells. He sent the young girl to the library to look for studies of the cancer rates among the Inuit, who eat staggering amounts of omega-3 fats. He thought that cancer might be rare among people who eat whales and seals. She came back to inform him that most of the Inuit eat spam and pancakes now, and struggle with alcohol abuse. Those still eating a native diet are being pursued aggressively by outsiders who don’t approve of the mercury and PCB content of their fat. Thus, they tend not to allow doctors to cut open their deceased, but they seem to have the same amounts of cancer that everyone else has. His struggle to build a coherent design around his life and work seemed to be faltering.

Winter passed and the summer came, giving her the chance to work in the lab full time. At night they would sit together in his office, reviewing their data, reading science journals and quietly murmuring questions or comments to one another. There was a paper that said 12-LOX was present in fish gills, so they went off in search of a rainbow trout. They rented a canoe. His eyes kept returning to the sweet, seductive hourglass shape of her waist and hips as she sat upright in the seat ahead of him, dipping the paddle into the water. They talked about meteors. Something he said amused her and she laughed, half-turning her head. Her eyes were deep green and sparkling like the river water.

In biological terms, they began to establish a pair bond. It’s something quite central to reproduction, especially in mammals like humans, where both parents care for the young. Pair bonding happens all the time. But in cultural terms, they were just skating on thin ice. He was married, and although she was not, she was quite young. When they were together in public, they did nothing to try to attract attention, but they did so anyway. It was a particular group of fortyish, frumpy women who seemed to notice them most. Angry women, their brains addled by pair bonding failures of their own, they scowled at the couple, their eyes filled with exasperation. In the stilted jargon of the day, they would have called her a victim. The more calculating terminology from an earlier generation would have labeled her lucky. The reality was that pair bonds are the subject of much scrutiny, debate, and even intervention in the society in which they lived. When the end of the summer came, she went back east to the University and their slow dance ended abruptly. Some cards and letters were exchanged. He came up for a weekend visit and they took a hike in the mountains. It was one of those unaccountably warm late October days, when the leaves seemed to bake on the woodland forest floor. All sorts of odors, musty and inviting ones, sweet and seductive, were in the air. They lay back in the softly crackling carpet of leaves and exchanged smiles. The tree branches rose high above them. The silence around them was full and pregnant, and each small whisper seemed to roar. The privacy of being alone together in a vast expanse of forest was quite intoxicating, and they did not return from the woods until dark. Nothing actionable transpired. She began studying for an exam, and he drove the rental car to the airport at an unnecessary speed. He was heading west for a fly fishing trip.

In the northwest corner of Wyoming there is a narrow, rocky valley flanked by tall mountains, and the Yellowstone flows deep and emerald green through it. Smaller streams cascade down the steep ravines, through dense stands of ponderosa pine and black fir. He was fishing in one of these, a torrent called Hell Roaring Creek. After working his way upstream past miles of rapids and black boulders glistening with spray, he came to a deep pool. For a brief space of twenty feet, the river stopped its headlong plunge down the mountain to form a crystal alcove. It was so calm and clear that he could easily see small pebbles on the bottom more than ten feet below. He slowly tied on a fly, a tiny puff of brown deer hair and yellow silk with a fine black barb barely visible at the end. The fly fell gently onto the surface. Almost at once a smooth, dark shape rose from the depths. A splash of burgundy red ran up the center of its bronzed side. Black speckles the size of peppercorns stood out so clearly on its broad green back that he could have counted them. It was a cutthroat trout, bigger and more beautiful than any he had ever seen. With a calm, deliberate sweep of the tail, the fish rose to within inches of the fly quivering on the water. The man drew in a sharp breath and swallowed, blinking rapidly. His wrist was trembling as he held the fly rod steady in the air. The vibrant shape below him seemed to dissolve and reform slightly displaced as gentle ripples passed over it. He saw the mouth open slowly, saw the crimson slash of color along the gills and the pale white of its inner lip. Seconds passed. He could smell the pungent wild mint that he was crushing beneath his bent knee. Then it was over. The fish whirled and streaked for the bottom. The violent sweep of its tail submerged the fly and sent water spraying into the air. For many minutes, the man remained crouched, frozen. He slowly reeled in his line, changed to a different fly, and set the new offering out onto the water. But the stark terror of vulnerability was now clear to the fish. It never showed itself again. It seemed as if an hour passed before the man was able to lift himself from the bank and continue upstream.

November came and a soft orange moon hung low in the sky. He left and traveled to Australia and Japan, disorienting his biological clock. He began to wake regularly at 1:00 a.m., when there was little to do except watch the moon moving slowly through the tree branches. He thought of her often, and when he did the image of the fish in Hell Roaring Creek kept pushing into his thoughts as well. At night it seemed that memories that had nothing really to do with each other got jumbled together, and then night after night they would come back again in the same order. The fish suspended in the crystal water became so blended with the memory of the color of her hair and the shape of her smile that he couldn’t think of one without seeing the other. It was months before he had a normal night’s sleep. He couldn’t escape the sadness that came over him when he thought of her, because he knew that if the fish had taken the fly, he surely would have killed and eaten it.