Slater took the cube, now in a glassine envelope, and several of the slides that had been prepared from its contents back at Camp Jackson, to the examining table at the far end of the room. All of this material had been declared utterly inert, and was used now solely for teaching and historical research purposes. But samples taken from it in 1996, then put through the polymerase chain reaction, had yielded enough information to enable the institute’s pathologists to reconstruct the entire genetic structure of the virus. Unlike this dead source material, the results of those molecular tests were now lodged, under the strictest security precautions, in little vials in a deep freeze in an undisclosed location nearly impossible to access, especially for someone with Dr. Slater’s compromised credentials. For him to get in touch with the origins of the epidemic whose victims’ graves he was about to desecrate, this musty archival material would be the closest he could come.

But something in his gut had told him that he needed to do it. Although epidemiology was often thought to be a cold-blooded discipline, one where its practitioners exercised objectivity and disinterested judgment in the face of appalling realities, Slater had never approached the job that way. He was a fighter, and in order to fully engage in battle, he needed some visceral sense of his enemy.

Though the electricians had done their best, the lighting at this spot was dicey; the brick ceiling was curved like a barrel, and the illumination from the lights mounted overhead was too bright in some spots and too weak in others. Slater found that he had to pull his stool first this way then that in order to keep the shadows from impinging on his work surface. Behind the walls, he could hear the muffled clanging of old pipes.

Private Vaughan had been a “well-nourished” young man, according to one of the documents he’d read that afternoon; another had called him “chubby.” He stood about five feet ten inches, and was, like most of the other infantrymen, eager to get to France before the fighting stopped. He had been trained, in the scrubby dunes around the camp, to maintain and deploy field artillery. But on the morning of September 19, 1918, instead of joining his platoon, he reported to sick bay, complaining of chills and fever. He was suffering from a dry cough, a dull headache, and his face was flushed. Although his heartbeat was regular, his throat was congested, and he said he was having trouble catching his breath. The doctor, who’d seen the flu before, consigned him to a cot.

But this was not like any flu the world had ever encountered.

Over the next few days, Private Vaughan got progressively worse. His fever rose, leaving him delirious much of the time and shivering under a pile of blankets that could never get high enough. His face took on a purplish tinge and his feet turned black. A secondary infection, pneumonia, set in, and his lungs began to fill with mucus. When he tried to speak, bubbles of blood broke on his lips, and while the doctors and nurses looked on in helpless horror, Private Vaughan slowly drowned in his own fluids. At 6:30 A.M. on September 26, he was declared dead.

Private Vaughan was the proverbial canary in the coal mine.

The Spanish flu, so named because it had cut a devastating path through Spain on its way to the New World, would eventually claim the lives of 675,000 American civilians. The body counts in other countries would be immensely higher. And before it had burned itself out, the fate of nations — and the planet itself — would be drastically altered. For those who thought the carnage of the First World War was the worst calamity humanity could endure, the Spanish flu proved them hopelessly mistaken.

Slater looked at the little cube of tissue-impregnated paraffin — once a chunk cut from a candle — and marveled at the devastation that it represented. Powering up the microscope, he slid one of the original slides, prepared by Dr. Hedgeforth, into view; the glass was so much thicker than current slides that he had to lift the eyepiece and do a bit of juggling to make it feasible.

He bent his head, made a few adjustments to the magnification, and observed a pale yellow background — a thin sliver of the paraffin — and in its center a dark smudge, like a crumb of burned toast on a pat of butter.

That smudge was a tiny piece of the private’s left lung, which had been so sodden and engorged with blood that Dr. Hedgeforth had said it looked like a slab of liver.

Even after all these years, the slides and candle wax gave off a whiff of formaldehyde, and the scent took Slater back to dissection labs and all-nighters in med school. As he studied the slides, and adjusted the magnification, he was able to bring out, in one of the last, a clearer view not only of the amorphous cells, faintly lavender and forever fixed in their positions, but fragments of the deadly virus that resembled bits of barbed wire. It was, he thought, like looking at an ancient battlefield — a place of death and destruction. You were looking back in time to something that had ended long ago but whose impression was even now unaltered. It was news from a world that had ceased to exist … news conveyed, in this instance, by a young soldier whose very essence had returned to the stars.

How long Slater stayed at it, he hardly knew. He lost himself in his research and his thoughts, the silence around him broken only by the occasional, distant clang of the heating pipes behind the old brick walls. In his own way, he was girding himself for combat. The enemy was right here, safely vanquished and preserved beneath the glass slide, but it was the same foe he would soon confront in the Arctic … though there, all bets would be off.

His thoughts had become cloudy — and he might even have dozed off on his stool for a few seconds — when he became aware that there was someone in the archway behind him. He slowly turned his head. One of the track lights hit him square in the eyes, and he had to raise one hand to shield his gaze from the glare.

For a split second, it was as if he was looking at the dead doughboy whose tissues he had been studying … but then the young man in the uniform spoke.

“We’re closing up, sir,” the night clerk said. “The archives open again at eight A.M.”

Slater nodded, then removed the last slide from the microscope, put the paraffin cube back into its glassine envelope, and slipped off his stool. He wobbled for a moment, but he ascribed that to having sat in one position for too long, and a precarious position to boot. He just needed to get the sample and the slides back in the drawer, go home, and get a good night’s rest.

Even the empty apartment seemed beckoning now.

Making his way under the archways, he felt an unexpected draft at his back and had to control the impulse to shiver as he passed the clerk, standing at the door with a set of keys dangling in one hand. It was only when he had rounded the corner and was safely out of the clerk’s sight that Slater dared to take his pill case from his pocket and, while leaning up against the redbrick wall of the corridor outside, quickly down a couple of the antimalarial pills dry.

Physician, he thought, with his eyes closed and his head spinning, heal thyself.

But when he opened his eyes again, his gaze was met by the silent stare of the siren baby, forever swimming in its formaldehyde jar. Would the Russian corpses, he wondered, be so well and safely preserved?

Harley Vane had been telling his story for days, but he was fast running out of new people to tell it to. By now, everyone had heard about how he had been out on deck overseeing the retrieval of the old casket, while Lucas Muller, that college boy, had altered the course of the boat to carry it too close to the rocks off St. Peter’s Island.