Lawrence argues that malformations can actually shed considerable light on the logic of life itself. For example, studying two preserved fetuses in John Hunter’s collection, Lawrence saw that a fetus could develop to a penultimate stage of development but lack a heart. Counterintuitive though it seemed, a human fetus could complete its formation (with minor morphological imperfections) without a rather essential vital organ. Lawrence underscored the importance of studying embryological monsters in order to unlock some of nature’s hidden secrets: “Monsters, in which considerable parts are wanting, seem peculiarly likely to assist in the prosecution of physiological researches. If we never saw animals, except in a perfect [fully developed] state, we could not form just ideas of the comparative importance of the different organs.” In fact, Lawrence argued, we would be led astray if we studied only the normal and the completed organisms. Because the heart and brain are so essential to the finished human, we might conclude that they are foundational for the developmental logic. But heartless fetal monsters are joined by equally surprising cases: the brainless and headless fetuses.
Acephalous (headless) fetuses were, and are, more common occurrences than one might imagine. Often the brain case is missing altogether and a truncated face terminates upward into a soft mass, sometimes covered by a smooth membrane. The neck is very short, making the reduced head sit almost directly on the shoulders, but hair often grows at the base of the cranium formation and “the body is well formed in every respect, and generally reaches the full size.” Lawrence explains, “These children generally die very soon after they come into the world; but they have sometimes lived for many hours, cried, sucked, &c.”41 The astonishing thing is that they should make it this far in the first place.
Terminal craniofacial anomalies like those studied by William Lawrence. Photo by Joanna Ebenstein © 2008. Reprinted by kind permission of the artist and the Museum of Anatomical Waxes “Luigi Cattezneo” (Museo Delle Cere Anatomiche “Luigi Cattaneo”), Bologna, Italy.
The lesson Lawrence draws from these cases is that there are two different physiologics to the human animal. Previously, scholars assumed that the complex organs (e.g., brain, heart) that play such a vital role in the functioning of the baby must also be essential to the construction of the animal in utero. But “the monsters just described,” Lawrence says, “prove that this is not the case.” We find instead that bones, cartilage, ligament, membrane, organs, cellular substance, intestines, and more can all be formed and become operational by the actions of the vascular system alone. A blood vessel system, Lawrence concludes, builds the body, and monsters have revealed this logic not only for themselves but for all humans. After birth, of course, a new logic kicks in and vital functioning cannot be sustained without a heart and a brain. Poetically stated, the monster points the way to scientific truths but pays the price with its life. All humans deviate or vary slightly, but when the variation is extreme they become monsters and nature spontaneously aborts them. If they should somehow survive this natural editing, then, Lawrence says, “the hour of their birth is with them generally the hour of their death.”42
Lawrence lays to rest three very popular misconceptions about monsters. Regarding the theory that a mother’s imagination can corrupt the fetus, he asks what sort of mechanical process could operate from the mother’s imagination down to the womb, where it would then have to destroy the normally developing head and reconstruct a new monkey head or whatever. Furthermore, there is extensive evidence that women can suffer serious disorders (e.g., diseases, amputations) with no ill effect on the fetus, so frights and imaginings seem far too weak for fetal reconstruction. Next, he counters the theory that extreme monsters, such as the headless children, are caused by blunt or acute traumas to the mother’s gravid abdomen. For one thing, a majority of cases of unfortunate offspring are born to women who suffered no such violence. For another, if the heads were caved in or broken in half we should discover some excess matter in utero and some bruising or signs of trauma.43
Lawrence also criticized speculative monsterology. Too many naturalists conducted their work by saying to themselves, and their readers, that “it seems reasonable that x should follow after y, therefore it must be the case that x follows after y.” Lawrence’s generation had grown tired of such teleological speculations, and he pressed embryologists to restrain their imagination when ignorant of the facts.44 Theorizing that these “illogical” things can’t be happening simply because they upset our deep assumptions about a rationally designed nature only stalls our empirical understanding of real biology.45
11
Darwin’s Mutants
Mr. Owen suggested to me that the production of monsters…presents an analogy to the production of species.
CHARLES DARWIN
It may be advantageous to turn to non-functional, grossly maladapted,
teratologies when studying the properties of internal factors in evolution.
PERE ALBERCH
AS FAR BACK AS THE ANCIENT Greek philosopher Empedocles, monsters have been considered possible jumping-off points for the evolution of new species. As we saw in part I, Empedocles speculated that prehistory contained a nightmarish environment of animated body parts, crawling around and clumping together until some accidental hybrids finally produced viable procreators. Nobody in Darwin’s era held quite so crude a theory, but it was entirely reasonable to consider the mysteries of species generation (transmutation or evolution) in light of individual generation (embryology). If monsters were individual deviations from the norm, then maybe they were the key to understanding species deviation. Did mutations in the individual lead to new branches on the phylogenetic tree?
MONSTERS AND TRANSMUTATION
In Darwin’s time high stakes were involved in issues of teratology. Every animal was seen as an example of God’s designing acumen, and because God was thought to be omnipotent, his animal designs should be absolutely perfect. Recall that it was difficult for medieval theologians to reconcile the existence of monsters with the omniscient, omnipotent, and omnibenevolent God. In that era, the problem was mostly about how to reconcile evil and evildoers with God’s obvious authority over the cosmos. Now, in Darwin’s era, the evil had largely gone out of the monster concept, but monsters continued to challenge assumptions about God’s ultimate authority over nature. Why would the perfect craftsman create (or allow) the imperfect craftsmanship implied by teratology?
The natural theologians tried to show that nature was elegant, economical, and rational, a perfect incarnation of God’s blueprint. During the 1830s a popular series of books called the Bridgewater Treatises endeavored to show how nature’s beautiful adaptations proved the existence of a divine architect. But it was becoming increasingly difficult to maintain this optimism when paleontology was uncovering massive evidence about extinct genera. Why would God retract whole orders and families of his beautiful creation? Were these “mistakes” in God’s overall plan? Was it even possible for God to make a mistake?
In addition to the theological threats from paleontology, the new work in embryology and morphology was also discovering some disconcerting truths about ontogeny. Natural theologians had built a professional industry on the demonstration of useful traits: the eye is designed perfectly for seeing, the canine tooth for tearing flesh, the neck of the giraffe for reaching higher foliage, and so on. For a mole, which lives underground, digging through dirt, normal eyes would only create an unhealthy nuisance; lo and behold, the Designer has seen fit to perfect the mole by withholding its eyes. But to this cheerful party of hand-in-glove correlations between structure and function came uninvited observations from anatomy. On closer analysis there appeared to be many structures that are not perfectly adapted to function. Recall Geoffroy’s and Hunter’s recognition that many animals with radically different life conditions nonetheless seemed to have similar structures; one finds a common pentadactyl forelimb structure, for example, in humans, whales, moles, and bats. Why would the Designer use th
e same structure for flying, digging, swimming, and grasping?
Homologies between different kinds of creatures did not sit well with natural theologians who saw each species as independently created by God. By the time Darwin was writing in his notebooks, the atheistic implications had been fully drawn out and emphasized against the more pious adaptationists. Significant anatomical structures did not have any obvious purpose in nature, and these anomalies threw doubt on the more general assumption that nature had been divinely designed. The morphologists, in contrast to the adaptationists, argued that a mole’s paws, a whale’s flippers, a human’s hands, and a bat’s wings all had similarities because nonpurpo-sive materialistic laws of embryological growth were shaping them. Radical anatomists, taking their start from Geoffroy’s ideas, began referring to the theologically minded Bridgewater Treatises as the “Bilgewater Treatises.”1
Monsters became part of the rallying cry of the radical atheists against a perfect, purposeful nature. Mutants and homologies theoretically conspired to undermine the Panglossian adaptation ideology of natural theology. Against this growing tide of atheism, Darwin’s colleague Richard Owen hatched two “curative” solutions. Owen argued that the structural homologies, emphasized by the morphologists, should not be seen as evidence against a divinely designed nature. Rather, these deeper unities underneath diverse species are actually transcendental archetypes: God’s blueprint plans for the animal kingdom. Owen eventually described an ideal vertebrate archetype that could be detected like a Platonic Form embedded in every snake, fish, monkey, and man. This clever move allowed natural theologians to concede that not every structure is perfectly adapted, but now this counterevidence that morphologists claimed as blind, nonpurposive laws could be seen as just more evidence of a divine hand in nature.
Now we can appreciate Owen’s second theoretical move: the idea, contra Geoffroy, that monsters are triggered by internal germ causation. Owen revitalized Hunter’s theory of monsters as an alternative to the blind view of nature that the radicals were preaching. If monsters, or pathological structures, are caused by anomalous conditions in their external environment, then changes in nature are accidental. Chance and contingency are the distressing implications of an exogenic theory of monsters. In other words, one child is born with two arms, but if we dial up the heat significantly (according to an exogenic view), we might end up with another child having four arms. Pure chance, not purpose, seems to be behind nature’s processes. To combat this accidental view, Owen argued that monsters resulted from preset changes in the germ, and this made room for the idea that monsters were purposefully caused.2
Owen offered a clever rescue, one that made sense out of the increasingly undeniable empirical data of transmutation, but also saved a role for God’s design. The rounded jigsaw skulls of vertebrate animals, for example, may originally have been a monstrous deviation from an ancestor, a tera-tological alteration of rostral vertebrae. But, according to Owen, such a monstrosity was preprogrammed by God and had led to an evolutionary jump, called saltation, a new kind of genus or order. The logic of monsters is synthesized with the idea of morphological archetypes if we consider that the homologies we see (the common body plans) are like footprints of the previous saltational monster jumps. God uses monsters to install his evolutionary designs over time, and the archetypes reveal to us some of those installation points.
Darwin’s Origin of Species was published in 1859, but long before that he was privately scribbling his theories in red notebooks. After his long journey on the HMS Beagle (1831–1836) he returned to London with a veritable treasure trove of exotic specimens, preserved animals, and strange fossils. At the same time that he was secretly writing notes to himself about transmutation, he was working with a variety of British naturalists to analyze, describe, and name his specimens. One of these new London friends, introduced by the famous geologist Charles Lyell, was the curator and anatomist Richard Owen. At the time, Owen was in charge of John Hunter’s collection, which was housed in the Royal College of Surgeons. Owen worked to describe Darwin’s specimens (including a giant sloth species that Owen named Mylodon darwinii), but he also exposed Darwin to the teratological interests of Hunter’s work.
It is clear from Darwin’s notebooks of the late 1830s that he became fascinated with the monsters in Hunter’s collection and Hunter’s opaque teratology theories. One idea that he underscored, even calling it “Hunter’s Law,” was that monsters varied according to laws.3 In particular, specific anomalies seemed to happen during certain times of gestational development. The unnatural positioning of limbs or organs happened during a certain week range, and the addition of digits or limbs happened during another range, and so on. These correlations were both species-specific and more generic. Darwin agreed with Owen, Hunter, and the Geoffroys that monstrosity had a law-like logic, but he was more interested in the implications of this for evolution than for embryology.4
Remember, Hunter thought monsters were already malformed in the germ code, but Geoffroy claimed they were the result of external mechanical influences of temperature or pressure. Owen sided vigorously with Hunter.5 At first, Darwin absorbed this whole debate and, following Owen’s suggestion, entertained the idea of monsters as launching points for species transmutation. But how, he still wondered, could such a launching point produce the amazing fit between a species and its environment? The theological solution seemed too incredible.
NO MONSTROUS JUMPS IN NATURE
In Darwin’s notebooks we see him sifting his way through these teratological issues, keeping the workable bits from his predecessors but ultimately finding his own way. He starts from the premise, pushed for by William Lawrence and other forerunners, that monsters are part of a larger biological phenomenon called variation.
But why do we recognize, he asked, that an albino is a monster variation, but a white-colored Arctic animal (e.g., an ermine hare) is an adaptational variation? Or similarly, why is a dwarf plant a monster in a temperate region but an adaptation in an alpine region? We have such variations as a six-fingered hand passed down from a parent (or even appearing de novo), but not related to the habit, function, or specific environment of the animal. Darwin says that some cases are obvious and easy to determine, such as when we discover nonfunctional traits: beetles, for example, “with wings beneath soldered wing-cases.”6 In those cases the oddities are inherited but they are not (at least currently) useful adaptations. But in the tricky cases, the only way of determining if a specific variation is an adaptation is to see if a subgroup of the larger family has a unique trait correlated with a unique habit of life. In other words, one would have to observe a subgroup of finches, say, with larger beaks, living successfully in a unique ecological niche away from the otherwise similar family of finches.7
Contrary to Owen, Darwin came to the conclusion that most monstrous variations were either too extreme for replication or just unrelated to environment (a characteristic they shared with most variations). However much Owen wanted to see macromutations as a first step toward new kinds of populations, empirical evidence from breeders and naturalists suggested otherwise.8
Darwin observed that hybrids either revert quickly to one of the parent types, or they do not reproduce at all. They fail utterly to spread their dramatic new traits to offspring; instead, such traits are lost in the next generation (if another generation is even possible). “An animal,” he writes, “is only able to transmit those peculiarities to its offspring, which have been gained slowly.” He continued to demonstrate his favorite rule, Natura non facit saltum (nature does not make sudden jumps), by pointing out that “mules have their whole form of body gained in one generation, so it is impossible to transmit them [to a subsequent generation].”9 Departures that are too far from the parents will always disappear quickly because “what has long been in the blood, will remain in blood.” Consequently, only slight variations, not monster jumps, will be passed down and possibly build up new populations gradually over time. So, althou
gh monsters are forms of variation, Darwin realized that they are not relevant variations for the transmutation issue. Monsters are either embryological mutants that cannot reproduce, or they reproduce (like six-fingered men) but don’t fit as adaptations, or they result from hybridism but again fail to reproduce.
By provisionally entertaining the monster theory of species transmutation, Darwin was able to better hone his own thinking about evolution. It was shortly after considering the mechanism of monster jumps that he famously discovered the economist Thomas Malthus’s theory of population reduction and applied it “not only to population and depopulation, but extermination and production of new forms.”10 The idea that environmental pressures could slowly shape the distribution of minor mutations and thereby adapt the populations to their conditions of life led Darwin to his mechanism of natural selection. The year 1838 was the turning point for Darwin; before that, he thought of monsters as a reasonable catalyst for evolution, but after the discovery of natural selection he rejected the role of monsters.
Monsters continued to intrigue Darwin in his mature writings, including Origin of Species and The Descent of Man, but they never again seemed compelling as nature’s primary mechanism of transmutation. In fact, he often pointed out that the only way monsters continued to thrive, reproduce, and even become subspecies was through the reckless arts of human breeding (artificial selection). Considering the odd differences between the greyhound, the bloodhound, the bulldog, and the Chihuahua, Darwin wrote, “Domestic races of the same species…often have a somewhat monstrous character,” in the sense that “they often differ in an extreme degree in some one part, both when compared with one another, and more especially when compared with all the species in nature to which they are nearest allied.”11 The unfortunate creation of freak animals is because “man selects only for his own good; Nature [by contrast] only for that of the being which she tends.” Unlike natural selection, which results from multiple causes such as food supply, weather and geological conditions, disease, and competition inside and outside the species, humans breed animals in ways that do not maximize the health and fitness of the animal.12
On Monsters: An Unnatural History of Our Worst Fears Page 20