A great debate that runs through the study of natural science was initiated by Aristotle, who analyzed the alternative models of development known as preformation and epigenesis. Preformationist theories assume that a minature individual exists in either the egg or the sperm and begins to grow into its adult form as a result of some proper stimulus.
Epigenesis, which aristotle favored, is based on the belief that each embryo or organism is gradually produced from an undifferentiated mass by a series of steps during which new parts are added.
Galen, the prolific Greek surgeon, was one of the few who disagreed with Aristotle’s epigenetic theory. In *On the Semen*, Galen disputed Aristitle’s idea that the female does not form any counterpart to the male semen. The female testes (uhhh - we would call them ovaries...), Galen argued, secrete semen into the horns of the uterus, where male and female sexual products mix with blood furnished by the mother to form the fetus. As the fetus developed, the liver, heart, and brain appeared. After the formation of the liver, fetal life was rather like that of a plan because it was nourished under the influence of the vegetative soul. With the formation of the heart, fetal life was like that of an animal because the heart served as the source of heat. Galen argued that the human beings are the most perfect of al the aimals, but man is more perfect that woman because the male has more innate heat (perhaps Mrs. Galen also liked to use him to warm up her cold feet...). Furthermore, it was a deficiency of innate heat that caused a fetus to become a female. As proof of his theory, Galen cited teh effects of castration. By removing heat, castration caused the body of a eunuch to become more like that of a woman.
Galen’s influence on early medicine was profound, and his legacy lasted longer than it probably should have. Spurred partly by the invention of the microscope and its window into the microscopic wold, the 17th century saw an eruption of interest in the theory of preformationism.
Two camps of preformationsists arose - the Ovists and the Spermists. The ovists believed that within the egg was a tiny preformed human, and within that another, and within that another, like a series of nesting dolls. If this ovum seed found fertile ground (a uterus), in the presence of fertilizer (the semen), it would start to grow larger and larger. Conveniently this allowed for all of humanity to have been created by God in one fell swoop at the moment of creation, which up some loose ends about “where do all these people keep coming from anyways.
The fact that this meant that within each woman was a series of people becoming smaller and smaller (to infinity?) was eagerly lapped up by scientists clutching their copies of Principia. Infinitesimally small people were a nice connection to the new field of calculus.
At the vangard of the preformationists was this famous microscopist - Antoni Van Leewenhoek. His microscope had opened up the squiggling world of the microscopic, and he was eager to find samples to examine - and he realized that he needen’t look farther than the ‘excesses of his conjugal relations’. Imagine his surprise after a bottle of merlot and an evening of Vivaldi, to examine his own semen and realize the cacophany of wriggling action therein.
Squinting closer at his homemade single-lensed microscope, Van Leewenhoek gasped in amazement - surely the little wriggling creatures were tiny people! It was not a set of nesting female dolls, but male dolls! Inside Adam’s testicles, at the moment of creation, was the whole human race...!
He hastily penned letters to colleagues and the Royal Society, including a number of figures depicting his tiny preformed humans. Worried that his studies would bring his peiosousness into question, he wrote that the samples were not obtained by any “sinful contrivance” but were made with “the excess with which Nature provided me in my conjugal relations”. But worried that the validity of his techniques be called into question added that the sample was examined before “six beats of the pulse had intervened” between ejaculation and microscopic analysis. Poor Mrs. Van Leewenhoek...
Ultimately, one of the nails in the spermist preformationist coffin was a theological one - van Leewenhoek realized that since sperm were so small that “a million would not fit in a grain of sand, there must be an enormous quantity in each sample of ejaculate. If each one of these sperm then contained within it an infinite series - the bedrooms of teenage boys are the sites of mass murder! Even the excesses with which nature provides during conjugal relations are a horrible waste. How could God be so callous and wasteful with his creation?
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