"Yes." It was my sister.

"She's on the line." Vince handed me the phone, and stepped back. I felt suddenly nervous. I glanced at my watch. It was eleven o'clock in the morning, time for Amanda's morning nap. She should be asleep in her crib by now. Then I remembered I had promised my sister I would call her at eleven to check in, to see how things were going. I said, "Hello? Ellen? Is everything all right?"

"Sure. Fine." A long, long sigh. "It's fine. I don't know how you do it, is all."

"Tired?"

"About as tired as I've ever felt."

"Kids get off to school okay?"

Another sigh. "Yes. In the car, Eric hit Nicole on the back, and she punched him on the ear."

"You've got to interrupt them if they start that, Ellen."

"So I'm learning," she said wearily.

"And the baby? How's her rash?"

"Better. I'm using the ointment."

"Her movements okay?"

"Sure. She's well coordinated for her age. Is there a problem I should know about?"

"No, no," I said. I turned away from the group, lowered my voice. "I meant, is she pooping okay?"

Behind me, I heard Charley Davenport snicker.

"Copiously," Ellen said. "She's sleeping now. I took her to the park for a while. She was ready to go down. Everything's okay at the house. Except the pilot for the water heater went out, but the guy's coming to fix it."

"Good, good… Listen, Ellen, I'm in the middle of something here-"

"Jack? Julia called from the hospital a few minutes ago. She was looking for you."

"Uh-huh…"

"When I said you'd gone to Nevada, she got pretty upset."

"Is that right?"

"She said you didn't understand. And you were going to make it worse. Something like that. I think you better call her. She sounded agitated."

"Okay. I'll call."

"How are things going out there? You be back tonight?"

"Not tonight," I said. "Sometime tomorrow morning. Ellen, I have to go now-"

"Call the kids at dinnertime, if you can. They'd like to hear from you. Auntie Ellen is fine, but she's not Dad. You know what I mean."

"Okay. You'll eat at six?"

"About."

I told her I'd try to call, and I hung up. …

Mae and I were standing by the double glass walls of the outer airlock, just inside the building entrance. Beyond the glass, I could see the solid-steel fire door that led outside. Ricky was standing beside us, gloomy and nervous, watching as we made our final preparations. "You sure this is necessary? To go outside?"

"It's essential."

"Why don't you and Mae wait until nightfall, and go out then?"

"Because the rabbit won't be there," I said. "By nightfall, coyotes or hawks will have come and taken the carcass away."

"I don't know about that," Ricky said. "We haven't seen any coyotes around here for a while."

"Oh hell," I said impatiently, turning on my radio headset. "In the time we've spent arguing about this, we could have been out and back already. See you, Ricky." I went through the glass door, and stood in the airlock. The door hissed shut behind me. The air handlers whooshed briefly in the now-familiar pattern, and then the far glass slid open. I walked toward the steel fire door. Looking back, I saw Mae stepping into the airlock. I opened the fire door a crack. Harsh, glaring sunlight laid a burning strip on the floor. I felt hot air on my face. Over the intercom, Ricky said, "Good luck, guys." I took a breath, pushed the door wider, and stepped out into the desert. The wind had dropped, and the midmorning heat was stifling. Somewhere a bird chittered; otherwise it was silent. Standing by the door, I squinted in the glare of the sunlight. A shiver ran down my back. I took another deep breath.

I was certain that the swarms were not dangerous. But now that I was outside, my theoretical inferences seemed to lose force. I must have caught Ricky's tension, because I was feeling distinctly uneasy. Now that I was outside, the rabbit carcass looked much farther away than I had imagined. It was perhaps fifty yards from the door, half the length of a football field. The surrounding desert seemed barren and exposed. I scanned the shimmering horizon, looking for black shapes. I saw none.

The fire door opened behind me, and Mae said, "Ready when you are, Jack."

"Then let's do it."

We set off toward the rabbit, feet crunching on the desert sand. We moved away from the building. Almost immediately, my heart began to pound, and I started to sweat. I forced myself to breathe deeply and slowly, working to stay calm. The sun was hot on my face. I knew I had let Ricky spook me, but I couldn't seem to help it. I kept glancing toward the horizon. Mae was a couple of steps behind me. I said, "How're you doing?"

"I'll be glad when it's over."

We were moving through a field of knee-high yellow cholla cactus. Their spines caught the sun. Here and there, a large barrel cactus stuck up from the floor like a bristling green thumb. Some small, silent birds hopped on the ground, beneath the cholla. As we approached, they took to the air, wheeling specks against the blue. They landed a hundred yards away. At last we came to the rabbit, surrounded by a buzzing black cloud. Startled, I hesitated a step.

"It's just flies," Mae said. She moved forward and crouched down beside the carcass, ignoring the flies. She pulled on a pair of rubber gloves, and handed me a pair to put on. She placed a square sheet of plastic on the ground, securing it with a rock at each corner. She lifted the rabbit and set it down in the center of the plastic. She unzipped a little dissection kit and laid it open. I saw steel instruments glinting in sunlight: forceps, scalpel, several kinds of scissors. She also laid out a syringe and several rubber-topped test tubes in a row. Her movements were quick, practiced. She had done this before.

I crouched down beside her. The carcass had no odor. Externally I could see no sign of what had caused the death. The staring eye looked pink and healthy. Mae said, "Bobby? Are you recording me?"

Over the headset, I heard Bobby Lembeck say, "Move your camera down."

Mae touched the camera mounted on her sunglasses.

"Little more… little more… Good. That's enough."

"Okay," Mae said. She turned the rabbit's body over in her hands, inspecting it from all sides. She dictated swiftly: "On external examination the animal appears entirely normal. There is no sign of congenital anomaly or disease, the fur is thick and healthy in appearance. The nasal passages appear partially or entirely blocked. I note some fecal material excreted at the anus but presume that is normal evacuation at the time of death." She flipped the animal onto its back and held the forepaws apart with her hands. "I need you, Jack." She wanted me to hold the paws for her. The carcass was still warm and had not begun to stiffen.

She took the scalpel and swiftly cut down the exposed midsection. A red gash opened; blood flowed. I saw bones of the rib cage, and pinkish coils of intestine. Mae spoke continuously as she cut, noting the tissue color and texture. She said to me "Hold here," and I moved my one hand down, to hold aside the slick intestine. With a single stroke of the scalpel she sliced opened the stomach. Muddy green liquid spilled out, and some pulpy material that seemed to be undigested fiber. The inner wall of the stomach appeared roughened, but Mae said that was normal. She ran her finger expertly around the stomach wall, then paused. "Umm. Look there," she said.

"What?"

"There." She pointed. In several places the stomach was reddish, bleeding slightly as if it had been rubbed raw. I saw black patches in the midst of the bleeding. "That's not normal," Mae said. "That's pathology." She took a magnifying glass and peered closer, then dictated: "I observe dark areas approximately four to eight millimeters in diameter, which I presume to be clusters of nanoparticles present in the stomach lining," she said. "These clusters are found in association with mild bleeding of the villous wall."