The roots of today’s battles over atheism, science, religion and climate change actually date back centuries
In the seventeenth century, most natural philosophers believed that every type of living organism on the face of the Earth had always existed, from the very beginning of the Earth’s creation. Every organism—every dog, every bird, every human being, and every worm—had been created by God in the form of something called “germs.” These germs were like the seeds of plants, scattered at the dawn of creation by God over the face of the planet, like a gardener would scatter a future crop. Germs were tiny, far too small to be seen even with the aid of a microscope. And each such germ contained even tinier germs, the germs of every successive generation that any creature would ever spawn. They were all stacked inside each other, like Russian nesting dolls. The infinite nature of the theory was the one thing that people had a hard time coming to grips with, but one of the theory’s most influential proponents, the French philosopher Nicolas Malebranche, would point out that it was no harder to believe in germs than in the life cycles of plants.* “One can say that in a single apple pit,” he said, “there would be apple trees, apples, and the seeds of apples for infinite or almost infinite centuries.”
Some believed that, in humans, germs were contained in male semen. Others saw them in the female’s egg. In France, the theory was called “embodiment”; in England, “preformation” or “preexistence.” It wasn’t just conjecture. Proponents of preformation could see the evidence all around them in the natural world. The transformation of caterpillars into butterflies was taken as a sign of God’s blueprint unfolding. The bulb of a tulip with its endless unfolding layers seemed a clue to the infinite layers of tulips that would spring forth, one after another. In the tiny eggs of frogs, microscopists thought they could see future generations of frogs waiting to be born. Those who believed in preformation were never short of evidence.
The theory was an old one, but it had gained traction in the late seventeenth century as a response to the theories of one of the most important thinkers of all time, René Descartes. Descartes’s great contribution to the natural sciences was to use his principles of deduction to understand a world whose workings, in his eyes, resembled that of a machine. Descartes carried this mechanical view of the world into what he hoped would be a great treatise on physiology. Yet the act of creation—the most important piece of the puzzle of life—continued to elude him until his final years. In the end, Descartes had settled on a theory that was purely physical, though the details were always sketchy. It was based on the mixing of sperm— something that, at the time, females were also commonly thought to produce. This mixing then led to a kind of fermentation in the womb. “If one knew what all the parts of the semen of a certain species of animal are, in particular, for example, of man,” he wrote in the posthumously published “De la formation de l’animal” in 1648, “one could deduce from this alone, by reasons entirely mathematical and certain, the whole figure and conformation.” He compared the process to that of “a clock, made of a certain number of wheels, to indicate the hours.”
According to preformation, God alone was responsible for the ultimate act of creation. Descartes’s version was creation by matter alone. His concepts of mechanical laws governing nature or the heavens could be accepted without discarding prevailing religious dogma. And indeed they were, especially in France. What most people couldn’t accept was his argument that human life owed itself merely to the workings of this vast machine. This seemingly small distinction marked a line that few dared cross. To do so was to invite the accusation of being a materialist—of believing in a world without any role for a grand creator—or even of being an atheist. French author Bernard de Fontenelle summed up the worries of many when he asked, “Do you say that beasts are machines just as watches are? Put a male dog-machine and a female dog-machine side by side, and eventually a third little machine will be the result, whereas two watches will lie side by side all their lives without ever producing a third watch.”
By the time Buffon sat down to write his own treatise of natural knowledge, the doctrine of preformation was still in vogue, even with most natural philosophers. But preformation didn’t sit well with Buffon. He was a materialist who saw the world much as Descartes did. Everything in nature, including the origins of living things, should be explicable by comprehensible laws. Preformation, he was sure, was little more than conjecture. But though he felt that Descartes’s version seemed closer to reality, he was aware the details were lacking. Then, Buffon was confronted by two discoveries that he thought could be clues to how living things were generated.
The first of these discoveries was made in 1741, near the Dutch seashore, where two little boys had spent a carefree morning roaming around the grounds of their father’s estate. They had come upon some tiny creatures in an inland pond, little curiosities, which were quarter-inch-long green specks that appeared to be wading in the water. The boys put them in a jar and took them home to their tutor, a Swiss naturalist named Abraham Trembley. Whether what Trembley’s charges had found were plants or animals was not clear at first. Whatever they were, they moved slowly—so slowly it was hard to tell whether they truly moved at all. But as the weeks passed, Trembley was quite sure that they did, in fact, move, if only an inch or two a day, and that they were indeed animals.
Trembley’s first thought was that he had discovered a completely new species. This would turn out to be untrue, as these tiny animals had already been identified by van Leeuwenhoek. The name van Leeuwenhoek gave them was “polyps,” though they would eventually be commonly known as hydras. They were strange creatures, to say the least. Beneath the lens of a microscope, they looked like a cross of a snail, an octopus, and a plant. As Trembley tried to learn more about the little creatures, he cut some of them in half. He was shocked to see that both halves continued to live. He wondered whether he was just witnessing residual movement akin to a severed lizard’s tail. Then something amazing happened. Each half polyp gradually began to regenerate the portions of its body that it had lost. Amazingly, the two halves became two separate creatures.
Trembley sent a summary of his results and a sample of the freshwater polyps to a well-known naturalist in Paris, René-Antoine Ferchault de Réaumur, an important skeptic of the doctrine of preformation who had written an influential paper about the regeneration of crayfish claws. Réaumur repeated Trembley’s steps, cutting the odd specimens into sections. He, too, watched in wonder as the little creatures he had split formed into entirely new creatures. “I could hardly believe my eyes,” he later wrote. “It is a fact that I am not accustomed to seeing after having seen it again hundreds and hundreds of times.” When he presented a demonstration to the Paris Academy of Sciences later that year, the official report on the event compared it to “the story of the Phoenix that is reborn from its ashes,” and asked witnesses to draw their own conclusions “on the generation of animals . . . and perhaps on even higher matters.”
The conclusion Buffon drew was that life was not nearly as clear-cut as preformationists would have people believe. The freshwater polyp’s ability to be split into two separate organisms did not, in his mind, fit the notion of preformation. He began looking for new explanations of how living things came about and found a possible solution in Needham’s observations of “eels” springing to life in water, which seemed to revive the idea of spontaneous generation. Buffon decided more investigation was warranted. His book would not shy away from dealing with the all-important question of how life begins. If an answer to this question was not known, he was going to find the answer himself. He wrote to Needham in London and invited the Englishman to join him at his home in Paris for experiments.
In the spring of 1748, Needham arrived in Paris. Buffon’s home was far more lavish than Needham could ever have imagined. His host was, by then, a fabulously wealthy man. Buffon’s noble title had, in fact, been acquired through his outright purchase of the entire French village of Buffon, from which he took his name. He actually came from a family of civil servants. He himself had been destined for such a career until he inherited a fortune from a childless uncle who had been tax collector for the entirety of Sicily during a period when the island had come under French rule. In the hands of a politically connected mathematical genius like Buffon, the fortune grew enormous.
The laboratory Buffon had set up for Needham filled an ornate drawing room, in the center of which was an intricately carved table well suited for fine dining, atop of which beautiful screens sat as dividers. This became the work space for Needham’s microscopes, which he had brought with him at Buffon’s request. Around the table, chairs were arranged so that Buffon’s acquaintances could watch the two men at work.
Little else was frivolous about their collaboration. Buffon normally worked fourteen-hour days, even when his health began to fail in old age. While he compiled his grand inventory, a servant was paid a gold crown every day just to wake him at five in the morning. His motto was simple: “Do not waste time.” He expected the same of everyone. Sometimes Needham worked alone while Buffon attended to his responsibilities at the Jardin du Roi or conducted research for his massive book project. Sometimes the two men worked side by side. They set about dissecting the reproductive organs of dogs, rabbits, and rams. Under the lenses of Needham’s microscopes, they examined the seminal fluids of all manner of creatures, even those of men, mapping out reproductive processes and searching for clues to a grand theory of how life began. They also searched for such clues in animalcules, where Needham’s interest and experience were sharpest. They repeated his experiments on wheat and refined them, hoping to strengthen their case for spontaneous generation.
Needham began experimenting on mutton gravy, something he knew to be teeming with the kinds of microscopic life he wanted to understand. He took a dab of this gravy and enclosed it in a glass vial, which he sealed with a cork. He sealed it yet again with resin, to be absolutely sure it was airtight. He then heated the mixture. All of this care and preparation were to ensure that nothing could contaminate the experiment, that no living egg would be present in the tube, and that a microbe too small to see could not find its way into the mixture.
Needham was quite sure that no egg could survive in the miniature environment he created. Nothing could. He let weeks go by before he opened his sealed tubes. “My Phial swarmed with Life,” he later wrote, “and microscopical Animals of most Dimensions, from some of the largest, to some of the least.” The experiment was repeated with different substances replacing the gravy. Each time, the result was the same. First, Needham would observe tiny particles that he called “atoms.” Day by day, these “atoms” grew and began to cling together until they became, in a couple of weeks, “the true microscopical Animals so often observed by Naturalists.” It was, in many ways, a repeat of van Leeuwenhoek’s experiment, with the same results that had so perplexed the Dutchman. For Needham and Buffon, it was clear that they had witnessed life emerge from nonlife, that they had witnessed evidence of spontaneous generation.
Needham published his work in the Philosophical Transactions in 1748, several years before Buffon would publish the results of their collaboration in his own book. This time, Needham went far beyond his first submissions. He had become bolder, more confident in the theories he had developed and perfected in the presence of Buffon’s inquisitive mind. He didn’t shy away from drawing conclusions that would make a mark on the world of natural philosophy. The spontaneous generation he witnessed, he argued, was not just the way some creatures reproduced. It was the method every creature used to reproduce. For, what were the spermatozoa he saw in his microscope if not little animalcules? He was convinced that these, and not the preformationists’ “germs,” were the true source of all life. He had discovered what he called a “vegetative force” that was the “one common Principle, the source of all, a kind of universal Semen.” Needham added something else about his discovery, something that went beyond the purely scientific. He said that his “universal semen” was proof of an “an All-wise Being, All-powerful, and All-good, who gave to Nature its original force, and now presides over it.” Not everyone would see it that way.
A year after Needham’s paper appeared in the Philosophical Transactions, the first volumes of Buffon’s simple “inventory” began to arrive in the bookstores of Paris. Released under the title “Natural History: General and Particular,” every available copy sold within a few weeks. The publishers rushed to keep up with demand. By the time Buffon was finished, Natural History comprised thirty-six volumes filled with gorgeous illustrations, including a plated illustration of Buffon and Needham at work in the laboratory.
In the second volume, Buffon unveiled his own grand theory of life. All organisms were composed of what Buffon called “organic molecules” that governed the life cycle from birth to death. For Buffon as it was for Descartes, life wasn’t especially different from any other phenomenon found in nature. “Living and animation,” he wrote, “instead of being a metaphysical degree of being, is a physical property of matter.”
Buffon believed these molecules continued to exist even after death, traveling through the air until they joined with other organic molecules and reassembled themselves, forming entirely new creatures that could be different by grades from the original. This was how he accounted for the gradations within species that so many natural philosophers had begun to notice. His theory may not have been correct, but it was, for the time, awfully good conjecture, and a decent precursor to Charles Darwin’s theory of natural selection. Even variations within the human race, Buffon believed, were a result of this phenomenon. Adam and Eve were Caucasians, while what he saw as lesser races were their descendants who had been made inferior by their weak environments.* As caustic as such views would sound a century or so later, they were almost progressive at a time when many thought of different races as altogether different species.
Buffon did something else in Natural History that would have historic implications. He used the word “reproduction” to describe the creation of offspring, a phenomenon previously referred to as “generation.” The term “reproduction” had first been used by Réaumur to describe regeneration such as that found in Trembley’s polyp, but Buffon used the word both in the regenerative sense and to describe the normal process of giving birth. While “generation” implied the blooming of a seed crafted by the hand of God, “reproduction” suggested replication, however inexact. Soon, more natural philosophers would begin to think of biology in terms of continuity, in terms of lines of descent.
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