Marker

BOOK DESIGN BY AMANDA DEWEY

This is a work of fiction. Names, characters, places, and incidents either are the product of the author's imagination or are used fictitiously, and any resemblance to actual persons, living or dead, businesses, companies, events, or locales is entirely coincidental.

For Jean and Cameron

and all they mean to me

I would like to acknowledge my medical school, The College of Physicians and Surgeons at Columbia University in New York. It was an honor and a privilege to have attended. Both my professional life and writing career have depended heavily on the foundation of knowledge and experience I learned and enjoyed at that fine institution.

—R. C.

PROLOGUE

IN THE WEE HOURS OF February
2,
a cold, steady drizzle drenched the concrete spires of New York City, shrouding them in a dense swirl of purplish-pink fog. Save for a few muted sirens, the city that never sleeps was at a relative standstill. Yet at exactly three-seventeen A.M., two nearly simultaneous, unrelated but basically similar, microcosmic events occurred on opposite sides of Central Park that would prove to be fatefully connected. One was on a cellular level, the other on a molecular level.

Although the biological consequences of these two events were opposite, the events themselves were destined to cause the perpetrators—all strangers—to violently collide in less than two months.

The cellular event occurred in a moment of intense bliss and involved the forcible injection of slightly more than two hundred and fifty million sperm into a vaginal vault.

Like a group of anxious marathoners, the sperm mobilized quickly tapped into their self-contained energy stores, and began a truly Herculean race against death: a remarkably arduous and perilous race that only one could win, relegating the others to short and frustratingly futile lives.

The first task was to penetrate the mucous plug obstructing the collapsed uterine cavity. Despite this formidable barrier, the sperm rapidly triumphed as a group, although it was a Pyrrhic victory. Tens of millions of the initial wave of gametes were lost in a form of self-sacrifice required to release their contained enzymes to make the passage possible for others.

The next ordeal for this horde of minute living entities was to traverse the relatively enormous uterine expanse, almost equivalent in distance and danger to a small fish swimming the length of the Great Barrier Reef. But even this seemingly insurmountable impediment was overcome as a few thousand lucky and robust individual sperm made it to the openings of the two oviducts, leaving behind hundreds of millions of unlucky casualties.

Still, the travail was not over. Once within the undulating folds of the oviducts, the fortunate ones who'd entered the correct tube were now spurred on by the chemotaxis of the descending fluid from a burst ovarian follicle. Somewhere ahead, beyond a tortuous and treacherous twelve centimeters, lay the sperm's Holy Grail, a recently released ovum crowned with a cloud of supporting cumulous cells.

Progressively goaded by the irresistible chemical attraction, a contingent of the male gametes accomplished the ostensibly impossible and closed in on their target. Nearly exhausted from the long swim and from avoiding predatory macrophages who'd engulfed many of their brethren, the number was now less than one hundred and falling rapidly. Neck and neck, the survivors bore down on the hapless haploid egg in a race to the wire.

After an astonishingly short one hour and twenty-five minutes, the winning sperm gave a final desperate beat of his flagellum and collided head-on with the egg's surrounding cumulous cells. Frantically, he burrowed between the cells to bring his caplike acrosome into direct contact with the egg's heavy protein coat to form a bond. At that instant, the race was over. As his last mortal act, the winning sperm then injected his contained nuclear material into the egg to form the male pronucleus.

The other sixteen sperm that had managed to reach the egg seconds behind the winner found themselves unable to adhere to the egg's altered protein coat. With their energy stores exhausted, their flagella soon fell silent. There was no second place, and all the losers were soon swept up, engulfed, and carried off by the deadly maternal macrophages.

Inside the now-fertilized ovum, the female pronucleus and the male pronucleus migrated toward each other. After the dissolution of their envelopes, their nuclear material fused to form the required forty-six chromosomes of a human somatic cell. The ovum had metamorphosed into a zygote. Within twenty-four hours, it divided in a process called
cleavage,
the first step in a programmed sequence of events that would in twenty days begin to form an embryo. A life had begun.

The nearly simultaneous molecular event also involved a forcible injection. On this occasion a bolus of more than a trillion molecules of a simple salt called potassium chloride dissolved in a shotglass volume of sterile water was injected into a peripheral arm vein. The effect was almost instantaneous. Cells lining the vein experienced a rapid passive diffusion of the potassium ions into their interiors, upsetting their electrostatic charge necessary for life and function. Delicate nerve endings among the cells quickly sent urgent messages of pain to the brain as a warning of imminent catastrophe.

Within seconds, the rest of the potassium ions were streaming through the great veins and into the heart, where they were propelled with each beat out into the vast arterial tree. Although progressive dilution occurred within the plasma, the concentration was still incompatible with cellular function. Of particular concern were the specialized cells of the heart responsible for initiating the heartbeat, those of the brainstem responsible for the urge to breathe, and the nerves and muscle spindles that carried the messages.

All were quickly adversely affected. The heart rate rapidly slowed, and the heartbeats grew weaker. Breathing became shallow, and oxygenation inadequate. Moments later, the heart stopped altogether, initiating progressive bodywide cellular death as well as clinical death. A life had been lost. As a final blow, the dying cells leaked their store of potassium into the stagnant circulatory system, effectively masking the original lethal bolus.

ONE

THE SOUND OF THE DRIPPING was metronomic. Somewhere out on the fire escape, drops of water, fueled by the incessant rain, splattered against a metallic surface.

To Laurie Montgomery, the noise seemed almost as loud as a kettledrum in Jack Stapleton's otherwise silent apartment, making her wince as she anticipated each splat.

The only competition over the long hours had been the refrigerator's compressor cycling on and off, the hiss and thump of the radiator as heat rose, and an occasional distant siren or horn, sounds so typical in New York that people's minds instinctively ignored them. But Laurie was not so lucky. After tossing and turning for three hours, she'd become hypersensitive to every sound around her.

Laurie rolled over again and opened her eyes. Anemic fingers of light reached around the window shade's edges, allowing her a better view of Jack's barren and otherwise drab apartment. The reason she and Jack were there instead of at her apartment was the size of her bedroom: It was so small that the largest bed it could accommodate was a twin, which made communal sleeping problematic. And then there was also Jack's desire to be near to his beloved neighborhood basketball court.

Laurie glanced over to the radio alarm clock. As its digital readout relentlessly advanced, Laurie became progressively angry. Without much sleep, she knew from sore experience she'd be a basket case at the medical examiner's office that day. She wondered how in God's name she had made it through medical school and her residency, where sleep deprivation had been the name of the game. Yet Laurie sensed that her current inability to fall asleep wasn't the only thing making her angry. In fact, her anger was probably why she couldn't sleep in the first place.

It had been the middle of the night when Jack had inadvertently reminded her of her upcoming birthday, asking her if she wanted to do something special to celebrate.

Laurie knew it had been an innocent question, coming as it did in the afterglow of love-making, but it had shattered her elaborate defense of taking each day at a time to avoid thinking about the future. It seemed impossible, but she was soon to be forty-three years old. Somewhere around age thirty-five the cliché about the ticking reproductive clock had become true for her—and now hers was sending out the alarm.

Laurie let out an involuntary sigh. In her loneliness as the hours had slid by, she'd fretted over the social quagmire in which she found herself ensnared. When it came to her personal life, things hadn't gone right since middle school. Jack was content with the status quo, as evidenced by his relaxed silhouette and the sounds of his blissful sleep, which only made things worse for Laurie. She wanted a family. She'd always assumed she'd have one, even during her comparatively wild twenties and early thirties, yet here she was, almost forty-three, living in a crummy apartment in a fringe New York neighborhood, sleeping with a man who couldn't make up his mind about marriage or children.

She sighed again. Earlier, she'd consciously tried to avoid disturbing Jack, but now she didn't care. She had decided she was going to try to talk with him again, even though she knew that the issue was something he studiously preferred to ignore. But this time, she was going to demand some change. After all, why should she settle for a miserable life in an apartment more suited to a couple of penurious graduate students than board-certified forensic pathologists, as she and Jack were, in a relationship where discussions of marriage and children were unilaterally verboten?

Yet things weren't all bad. On the career side, it couldn't be better. She loved her job as a medical examiner at the Office of the Chief Medical Examiner of New York, where she'd been working for thirteen years, and she felt lucky she had a coworker like Jack with whom she could share the experience. Both of them were awed by the intellectual stimulation that forensic pathology offered; each day they learned something new. And they saw eye to eye on a lot of issues: Both had little tolerance for mediocrity, and both were turned off by the political necessities of being part of a bureaucracy. Yet as compatible as they were work-wise, it did not make up for her burgeoning desire to have a family.

Jack suddenly stirred and rolled over onto his back, his fingers intertwined and hands clasped on his chest. Laurie looked at his sleeping profile. In her eyes, he was a handsome man, with closely cropped, gray-streaked light brown hair, bushy eyebrows, and strong, sharp features, usually sporting a wry smile, even in repose. She found him aggressive yet friendly, bold yet modest, challenging yet generous, and, most often, playful and fun. With his quick wit, life was never dull, especially with his adolescent penchant for risk-taking. On the negative side he could be aggravatingly stubborn, especially about marriage and children.

Laurie leaned toward Jack and looked more closely. He was definitely smiling, which aggravated her irritation. It didn't seem fair that he was satisfied with the status quo.

Although she was reasonably sure she loved him and believed he loved her, his inability to make a commitment was literally driving her to distraction. He said it wasn't a fear of marriage or parenthood per se, but rather the vulnerability that such commitment created. At first, Laurie had been understanding: Jack had suffered the tragedy of losing his first wife and two young daughters in a commuter plane crash. She knew that he carried both the grief and the responsibility, since the accident had occurred after a family visit while he was retraining in pathology in another city. She also knew that after the accident, he had struggled with severe reactive depression. But now the tragedy was almost thirteen years in the past. Laurie felt that she'd been sensitive to his needs and had been patient when they finally did start dating seriously.