The Seeds of Life Page 7

  A jangle of contradictions, Harvey was a bluff countryman who retained his taste for plain food and plain speech but was friend and companion to kings. He was jumpy and restless but cool in circumstances that rattled everyone else. (During the battle of Edgehill, in the English Civil War, Harvey was entrusted with watching over the king’s two young sons. At one fraught moment, he curled up under a hedge with the boys and took out a book. “But he had not read very long,” a friend wrote afterward, “before a bullet of a great gun grazed on the ground near him, which made him remove his station.”) He was a staunch conservative but, when it came to science, a revolutionary.

  Most important, he was a medieval man at home in a spirit-haunted world and, at the same time, a modern scientist who helped topple that world. Witches still flew through the night in the 1600s, for instance, and Harvey was once sent (by Charles I) to examine a suspicious old woman. Everyone knew about witches. They knew about spells and potions; they knew that witches rubbed their bodies with the fat of murdered babies so they could slither through tiny cracks into their victim’s homes. They knew, too, that Satan provided witches with animal companions who helped them in their dark schemes.

  Harvey asked to see this woman’s “familiar,” which turned out to be not a black cat but a toad. He invented an errand and sent the woman on her way. “His tongs were ready in his hand,” an acquaintance of Harvey’s recalled, “and he catched up the toad in them. His dissecting knife was ready also.… He examined the toad’s entrails, heart, and lungs, and it no ways differed from other toads, of which he had dissected many. Ergo it was a plain natural toad.”

  FIGURE 6.1. Harvey was physician to King Charles I, who encouraged his scientific investigations. England fell into civil war in the 1640s, and the king was beheaded in 1649. Charles in good times (left) and bad (right).

  So much for the black arts. The belief in witches dated back to ancient times. The faith in experiments was brand-new. Harvey and his fellow scientists, who believed in alchemy and unicorns and astrology, managed somehow to navigate a world that contained both.

  Over a span of many years, Harvey would devote all his intellectual powers to unraveling the riddle of sex. Curiously, he found the whole business off-putting. Sex, “which is itself loathsome,” did not inspire him to flights of poetry. But if Harvey did not have much of a lyrical streak, he did have a host of strengths, notably a gift for devising decisive experiments, persistence verging on obstinacy, and a skillful way with a scalpel.

  He had unveiled his new picture of the heart in 1628, in a skinny book called On the Circulation of the Blood. The title proclaims the breakthrough. Long before Harvey, it had been known that blood moved within the body, but the word “circulation,” if it was used at all, referred to a slow, haphazard drift, like the circulation of air in a house.

  Harvey proved that the truth was far different. He showed conclusively the falsity of the traditional belief that the body contained two distinct kinds of blood, which sloshed their way along separate pathways and nourished different organs. On the contrary, the same blood made circuit after vigorous circuit around the entire body, nourishing as it travelled, and propelled by the muscular heart.*

  Harvey’s notion of a quick, purposeful round-trip was startling and new; the description of the heart as a pump was revolutionary. This was not simply a new explanation but a new kind of explanation—a mechanical account of what had long been literally a sacred heart. That lofty organ was suddenly brought to earth, transformed not merely into a machine but, jarringly, into a machine made of slick, dark meat.

  Around 1630, fresh from sorting out the heart, Harvey turned to what was then known as “generation,” a broad heading that encompassed all the mysteries of sex, conception, and development. His study of life began with a plunge into death.

  That was unavoidable, though it was ugly, because understanding the workings of the living machine required, as a first step, identifying its parts. This was the biological counterpart of disassembling a balky toaster or a misbehaving car engine and laying the parts out on a workbench. But this body shop was the real thing.

  FROM EARLY ON, HARVEY HAD HARBORED A PASSION FOR ANATOMY and dissection. “The examination of the bodies of animals has always been my delight,” he wrote, and he seemed untouched by the distaste for blood and gore that softer souls like Leonardo had to fight down. (Leonardo was so fervent an animal lover, according to his admirers, that he bought caged birds in order to set them free.) Any creature that hopped or flew or slithered or swam—some sixty species in all, by one biographer’s tally—was likely to find itself pinned beneath Harvey’s knife.*

  Harvey probed the bodies of dogs, pigs, snakes, shrimp, frogs, oysters, and lobsters, as well as countless birds. He dissected hens by the flock, and studied their eggs with minute attention. Traveling through once-lush regions of France and Spain in 1631, a time when war and plague had emptied the countryside, Harvey lamented that “we could scarce see a dog, crow, kite, raven, or any other bird, or anything to anatomize.” (As for the humans, Harvey noted grimly that “famine had made anatomies before I came.”)

  Harvey’s fascination with dissection extended even to his own family. He observed the autopsy of one of his brothers and remarked with curiosity that he had “a spleen hanging like a letter V.” A few months later, when Harvey’s father died, Harvey dissected the old man himself. (This was one last good deed on the part of a proud parent, according to one biographer, “Thomas encouraging his son’s medical studies in death as well as in life.”) Peering intently at the organs glistening within his father’s open body, William Harvey took special note of the “huge” colon.†

  TO CRACK THE SEX RIDDLE, HARVEY NEEDED TO FIND A WAY TO frame the essential facts so boldly that the truth shone out. Science is the study of the real world, but the game always starts with turning away from reality for a time rather than confronting it. The trick is to find a stripped-down, simplified version of the world that can stand in for the real thing. Reality is too complicated to tackle head-on; a map is a better guide than the territory itself.

  Isaac Newton found that the cosmos could never be described tidily, for instance, as long as he pictured the Earth and moon as the immense, complicated structures that they are. But instead of thinking of them as huge, rocky lumps pulled this way and that by a myriad of other lumps, he imagined them as two isolated, featureless points in a mathematical drawing. Suddenly the heavens fell into place.

  Harvey had mastered that game. Before he came along, the heart had lain wrapped in mystery. That darkness had stretched out for thousands of years. As soon as Harvey saw that “the heart is a pump,” the mystery nearly solved itself. Now he meant to do something similar to explain sex.

  As usual, the problem began with sorting out the role of women. What was it exactly that they contributed to the making of a new life? The trouble, which was a sign of a field in its infancy, was that Harvey had too many theories to pick from. He passed over the first, without even bothering to reject it explicitly. This was the age-old doctrine of woman-as-field, which implied that the woman made no contribution at all to the new generation. Harvey deemed that impossible, essentially on philosophical grounds, as a scientist today might reject the possibility that aliens built the pyramids. Whatever was true, that could not be.

  That still left two theories of the case, and they didn’t fit together. Both dated to ancient times. Both had hordes of clamorous supporters. Both rested on analogies that struck their partisans as self-evident.

  One theory held that women were like men. Since men produced a fluid that played an essential role in conception, women must produce a similar fluid of their own. The second theory compared women not to men but to other female animals. Those animals produced eggs, the age-old symbol of fertility. Since women’s reproductive anatomy resembled that of these egg-laying animals, women must produce eggs.

  Harvey, a master of anatomy and an ingenious experimenter, belonged to the egg c
amp. Since ancient times, humans had watched chicks emerge from their eggs. Though no one had ever seen anything like an egg in mammals, many anatomists felt sure that such eggs must exist. So Harvey believed, fervently. At the time, his view was in the minority.

  In the mid-1600s, Harvey’s era, most medical authorities still echoed a view that Galen had set out fourteen centuries before. Women and men were variations on a theme. The two sexes were nearly identical in structure and function. They joined together in sex; they both carried on with enthusiasm and vigor; they both emitted fluids in the course of the action; they both reached orgasm. It stood to reason, Galen and his followers decreed, that if semen was the male contribution to conception, then the female contribution was some corresponding semen.

  The one-sex model, as Galen’s theory came to be known, held that women and men were anatomical twins. When it came to obvious features like eyes and ears and hands and feet, male and female plainly corresponded. The surprising claim of the one-sex model was that, structurally and anatomically, the sexual parts matched, too. This unlikely doctrine reigned for a millennium and a half.

  The comparison required a bit of hard-to-follow scientific hand waving. With a bit of presto, change-o, testicles became ovaries, the penis became cervix and vagina, the scrotum became the uterus. Vesalius’s Fabric of the Human Body is jammed with unsettling pictures meant to show, in the words of the historian Thomas Laqueur, that “the vagina really is a penis, and the uterus a scrotum.”

  As late as the 1700s, the most popular sex manual of the day held to the one-sex view, and even managed to put it in rhyme:

  For those that have the strictest searchers been

  Find women are but men turned outside in

  And men, if they but cast their eyes about

  May find they’re women with their insides out.

  The anatomists and physicians themselves had no doubt they had uncovered a vital truth, though perhaps one hard to convey. Laqueur compares their accounts to those you sometimes read today when scientists try to explain curved space and higher geometry, and go on about how a coffee cup and a doughnut are “really” the same because if they were made of modeling clay you could transform one into the other. For the public in centuries past, only halfway paying attention to such squabbles, the very obscurity of the purported explanations may have given them credibility, on the grounds that what sounds difficult must surely be deep.*

  But the one-sex doctrine had more in its favor than an air of profundity. A man’s testicles and a woman’s ovaries did seem to match up, more or less—both came in pairs, both were near the belly, and both had something to do with sex. (For thousands of years, farmers and herders had castrated and spayed their animals. Mysteriously but reliably, this rendered a whole variety of creatures—cattle, horses, pigs, dogs, even camels—more manageable. More important, it kept them from reproducing without seeming to do any lasting harm.)

  The evidence from spaying and gelding was not conclusive. No one could explain how it worked, for starters, and perhaps the procedures did do some subtle damage. You could imagine that surgery that injured an animal’s heart, say, might make it placid and uninterested in mating. But that would not prove that the heart played a direct role in sex; perhaps the poor animal was simply too weak or wounded to carry on.

  Still, even if the case for the one-sex model was not airtight, it seemed plausible. The rival camp spoke confidently of mammalian eggs, but, in these premicroscope days, no one could be certain such things even existed. Then what? If the “female testicles” didn’t produce eggs, what could they be for, if not producing a female semen? This was seen as a strong argument, because everyone agreed that every structure in the body has a purpose. “Nothing is accidental in the works of nature,” Aristotle had declared. “Everything is absolutely for the sake of something else.” From the Greeks through Leonardo and Harvey, everyone echoed the point. Nature’s designs, or God’s, contained no unnecessary features.

  When it came to sex, this innocuous-sounding doctrine played out in surprising ways. Women’s orgasms, for instance, could not just be a source of happiness; they had to have a purpose beyond mere pleasure. “When also in coition ye observe the same delight and concussion as in Males,” asked the English scientist Nathaniel Highmore, in 1651, “why should we suppose Nature, beyond her custom, should abound in superfluities and useless parts?”

  The unlikely consequence was that, in one remarkable way, conventional medical wisdom did right by women. This good deed was inadvertent, and it marked the very centuries when women were routinely maltreated or disdained. But if Galen was correct in saying that both women and men produced semen, then it followed that women, too, had to reach orgasm if they were to conceive. And the birth of children was hugely important. So women’s orgasms were a matter of great concern, and not only to the women involved.

  Across Europe and throughout the Arab world as well, physicians provided males quite specific advice on sexual technique. “Men should take their time playing with healthy women,” wrote the Islamic physician Avicenna, in a celebrated work called the Canon of Medicine. “They should caress their breasts and pubis, and enfold their partners in their arms without really performing the act. And when their desire is fully roused, they should unite with the woman rubbing the area between the anus and the vulva, for this is the seat of pleasure. They should watch out for the moment when the woman clings more tightly, when her eyes start to go red, her breathing becomes more rapid, and she starts to stammer.”

  Sometimes ignorance is bliss.

  PROPONENTS OF THE ONE-SEX MODEL BOLSTERED THEIR CASE with other observations. Even supposing for the sake of argument that women did have eggs, why were there two ovaries but, usually, only one baby? And how would those hypothetical eggs make their way to the womb? The Fallopian tubes seemed the natural route, but they did not quite reach all the way to the ovaries. Did the imaginary egg leap across that very real gap?

  Wasn’t it more likely that women produced a sexual fluid corresponding to a man’s semen? Better yet, didn’t the theory that two semens mix together explain why babies so often inherited features from both parents?

  On the other hand, the argument in favor of the one-sex model had problems. Harvey ridiculed it. It was true, he agreed, that “during intercourse the male and female dissolve in one voluptuous sensation.” But to say that both sexes melted deliciously was a long way from proving that both sexes produced semen. The theory could not be true in any event, Harvey snarled, because female genitalia were not on a par with the male’s. “I, for my part, greatly wonder that from parts so imperfect and obscure, a fluid like the semen, so elaborate, concoct, and vivifying, can ever be produced.”

  That was name-calling, not science, but the one-sex model had confronted more serious challenges. It had even outlasted the “discovery” of the clitoris by an anatomist named Renaldus Columbus in 1559. The clitoris was “pre-eminently the seat of woman’s delight,” Columbus told his readers. “If it is permissible to give names to things discovered by me, it should be called the love or sweetness of Venus.” This was a bold claim. Like Christopher Columbus before him, Renaldus Columbus had “discovered” territory that the natives had explored on their own eons before.

  But, priority aside, this was confusing. Galen had declared that it was the vagina that was, anatomically, the counterpart of the penis; a second counterpart seemed too much of a good thing. Proponents of the one-sex model never flinched, though they did quarrel over just which bit of female anatomy was more akin to the penis.

  They might have questioned their theory more vigorously had the whole debate not slipped away from specifics into a lament about the imperfect design of female bodies generally. Though the structures of the two sexes matched, Galen and his followers explained, the male versions were superior. The male was the template, the female a flawed and clumsy imitation, like a child’s drawing of a Greek statue. (Through all these centuries, the female reproductive organs
had no names of their own but were referred to by the names of their male counterparts.)

  Physicians and biologists remarked again and again that the male apparatus was proudly exhibited while the female counterparts were relegated to the body’s unseen interior, the fit home for the inferior and the undeveloped. Galen made a rueful comparison between a woman’s reproductive organs, hidden away, and a mole’s tiny, deep-set, and nearly useless eyes.*

  Lest we reject Galen’s views as the kind of ancient folly we have long since outgrown, we should note that nearly two thousand years after his death, physicians continued to draw damning conclusions from what they called female “interiority.” “Their secret internal organs, women were told, determined their behavior,” notes one history of nineteenth-century medicine. “Their concerns lay inevitably within the home.”

  THOSE THINKERS UNWILLING TO FULLY ENDORSE GALEN’S MODEL could opt instead for a modified version of his theory. This one had an even more impressive pedigree; it dated to Aristotle, a brilliant observer of the natural world and biology’s founding father, who flourished around 350 BCE. William Harvey, disdainful of Galen but a devoted admirer of Aristotle, gave it a hard, serious look.

  Like Harvey and Galen, Aristotle rejected the notion that women served merely as the field where the male seed grew. On the contrary, he insisted, women did contribute something physical and tangible to conception. But this substance was not a female semen. It was menstrual blood.

  Galen had argued by analogy: male and female reproductive structures looked alike (to a generous eye) and therefore they functioned alike. Aristotle’s argument relied on a different analogy. It, too, required a certain openness of mind. “Wait a second, hear me out,” you can almost hear Aristotle plead, as his fellow investigators rolled their eyes and clutched their tunics in dismay.