The Ovary of Eve: Egg and Sperm and Preformation.

Clara Pinto-Correia has written a book as unusual as her own career. She is not only professor of developmental biology at Universidade Lusofona in Lisbon, Portugal, she is the author of several books of poetry and six novels. Perhaps it is her novelist's bent that has produced such an extraordinary work in the history of science. The dominant literary form for stories in science is melodrama: the brilliant discoverer (Gallileo, Darwin, Freud) is reviled by the conservative establishment, wages a valiant battle for truth, and is finally vindicated. The hero eventually wins. Pinto-Correia tells the tale of earlier embryology as epic: no heroes, no villains.

In one sense this account of seventeenth- and eighteenth-century reproductive biology must be without heroes because both sides were dead wrong - or so it seems. Strange as it may sound, the dominant theory to explain biological reproduction was "preformationism": all the generations since Eve were nested inside one another like so many Russian dolls. Gestation and birth were just a matter of these minute creatures growing to proper size. Given the assumption of preformation, the major dispute was whether the animalcules were lodged in the egg or the sperm. Ovists and spermists contended for the honor, an honor which, of course, belongs to neither the ovary of Eve nor the sperm of Adam.

But Pinto-Correia's book is epic at a much deeper and even more traditional level. As in Homer and Dante, the book involves a revelatory trip to the underworld. It is the "underworld" which dominates preformationist theory. The "underworld" of seventeenth-century biology was the world of the minute revealed for the first time by the microscope. All of a sudden the world was filled with all sorts of miniscule creatures whose existence had never been suspected. The discovery of sperm itself was fantastic - so many thousands of "worms" lashing about that even today with highly sophisticated instruments it is extremely difficult to obtain a very exact count. And then there was the great model of Newton: if the universe extends outward into a sea of infinite space and time, perhaps the world extends downward toward infinities.

Preformationism was not, however, merely a rash extension of microscopy; it seemed the rational alternative to its only basic rival: epigenesis. Epigenesis seemed to claim that organisms began in an homogeneous state and that the embryo was molded into form solely from external stimuli. Epigenesis had a difficult problem with the obvious persistence of species; lacking an explanation for regularized form, the theory ran counter to scientific rationalism's demand for an explanation for species re-production. Caspar Wolff (1734-94) who is generally credited with the definitive refutation of preformationism because of his careful description of the development of organs in chick embryos, nevertheless "to sustain this theory of creation de novo...postulated that the embryo was created by an invisible force, the vis essentialis.... "Scientific rationalism wanted a mechanism, not an invisible force, hence the theory of pre-formation.

Continuing with the epic muse, Pinto-Correia includes as vital actors in her story all manner of wonders: dwarfs, monsters, and the gods. Nothing could be more "dwarfish" than the homunculus, the tiny pre-formed little person crouched in a sperm cell which Nicholas Hartsoecker depicted in an infamous drawing of 1694. (Homunculus was not the term used by these earlier researchers, rather it appears to be a term of opprobrium foisted upon them by self-assured twentieth-century historians.) Monsters (deformed progeny) in turn were a great problem for all the preformationists; if God had incapsulated all generations from the beginning, what was the point of such aberrations? Finally, since all these early scientists were determined Christians - the greatest of them, and Pinto-Correia's only possible hero, was the priest Spallanzani - there was continual and powerful interplay between theology and biological theory.

One can sense the theological import from difficult issues faced by spermists and ovists respectively. Under the general preformationist assumption, various savants championed either the ovum or the sperm as the locus of the prior form. The spermist camp had insuperable theological problems, however, because of the profusion of sperm. If there really was a pre-formed human in each sperm, what was the spiritual fate of all the sperm-persons who never connected with an ovum? Ovists, on the other hand, suffered from what Pinto-Correia labels "the curse of the left testicle." Folk and some learned lore had it that women were produced when sperm of the left testicle was involved in gestation; men were produced by the right. The left is feminine (sinister, Lat.). Why would God chose to bundle the human race into the lesser, sinister female?

Pinto-Correia is by no means confined merely to Christian overlay. She ranges about the world's creation myths from the pyramids to Polynesia, as she demonstrates our fascinating attempts to find some connection between human meaning and the mysteries of nature. There are many reasons for reading this work: a delight in the curiosa which abound in this early science: Jablot's drawing of a microrganism with a mustache, Dalenpantius's little-man-in-the semen who is wearing a hat. ("I have seen this thing with my own eyes....") One can learn the lesson that instrumentation not only reveals, it also misleads; then the microscope, now the computer with our present temptation to reconstruct human thinking as computation. The embryology of the seventeenth and eighteenth century offers a compelling case study of the intersection of so-called "pure science" with everything from theology to politics. (Preformation was a wonderful prop for the stability of social class, kings produce kings, commoners replicate from generation to generation. Epigenesis suggests that everyone starts homogenous, equal - an embryology for democracy.) Finally, one should not think that the basic issues have been put to rest. In the final chapter, "The Fat Lady Will Not Sing," Pinto-Correia notes the preformationist aura of The Bell Curve (published 1994) which argues that "our mental limits are established at fertilization." She concludes: "Nobody said that reproduction was an easy matter during the Scientific Revolution, but the subject has not become any easier today...."

Dennis O'Brien's most recent book is All the Essential Half-Truths about Higher Education (University of Chicago Press).