A madcap theory of yesteryear ~ Spontaneous Generation
“Genetics is a way to make all of your flaws your parents’ fault.”
The following is what you might call a “How could they believe such claptrap?” story. So, hold on, because we are going to explore how and why some humans believe the most bizarre ideas.
On my kitchen counter sits a half-gallon metal container labeled COMPOST. I only use it for coffee grounds, which I mulch into my raised bed garden. When I remove the non-sealing lid in the summer months to add the day’s coffee grounds, there are always small maggots wriggling about in the dark grinds.
Of course, we know now that the ever-present fruit flies, an unwanted gift of summer, are responsible for these larvae. However, until the 18th Century, scientists of the day widely believed that the disgusting little creatures arose spontaneously from the medium, rather than being a product of the fruit fly, a process known as spontaneous generation.
This article will discuss two distinct theories regarding the origin of living organisms: biogenesis and abiogenesis. Biogenesis is the theory that life can only originate from pre-existing life, while abiogenesis theorizes that life can arise from non-living matter.
Theories come and go as ongoing research discovers new facts. This persistence of scientific inquiry is what led to the overturning of many long-held beliefs. For example, at one time it was widely believed that the Sun revolved around Earth, that we were the center of all that is. This belief prevailed until the 16th Century when the heliocentric model was introduced by Copernicus and confirmed by Galileo.
Theories are not necessarily factual but rather are subject to the discovery of new and previously unknown facts. However, for this discussion about the dismantled theory of Spontaneous Generation, we will focus on assumptions derived from both demonstrable experiments and those that did not employ the scientific method.
As the subtitle suggests, we will be discussing a theory about how life came into being that was internationally accepted as fact for millennia, ie, spontaneous generation.
Aristotle, the great philosopher of ancient Greece, was also one of the first real scientists. He was an astute observer of nature in addition to his many other fields of interest. His belief in spontaneous generation was predicated upon what he observed in mud and its constituent non-living properties. This emphasis on observation as a key tool in scientific discovery is a recurring theme throughout this discussion.
Aristotle noticed that in the spring, there were small fish, worms, frogs, and even eels emerging from the mud. From his observations, he deduced that these, by and large, small creatures were animated by a substance called pneuma or vital heat, bypassing sexual reproduction altogether.
Author’s Note: Most thinking people today would reject the notion of spontaneous generation outright, but remember that our ancestors, lacking the advantages and insights of the Scientific Revolution of the 17th Century, believed many things we would repudiate today. After all, the Age of Enlightenment had yet to reach the shores of North America, as evidenced by such things as the Salem Witch Trials of 1692.
The belief that living creatures could arise from non-living matter prevailed for centuries, with proponents contriving various flawed experiments as proof of their theory. Of course, the Catholic Church did not accept spontaneous generation, and likely other denominations as well, because it contradicts Genesis.
The first challenges to the theory of spontaneous generation began in the 1600s. They continued until a final showdown between a French proponent of spontaneous generation, Félix Pouchet, and an up-and-coming French chemist named Louis Pasteur.
Before we examine the experiments that disproved the theory of spontaneous generation for all time, we should review some of the flawed attempts by proponents of the theory that divided the scientific community into two camps of belief.
To prove their theory that life arises out of non-living matter, the spontaneous generation fans would put a nice sirloin steak in an uncovered jar and sit back and wait. Sure enough, it wasn’t long before an army of maggots began tenderizing the meat. “See,” they would exclaim, “Those maggots didn’t need a mother or father, they arose from the meat itself.”
In response to this ludicrous assertion, the biogenesis crowd set up the same experiment, except they placed an airtight lid on the container and monitored it for days; however, no maggots appeared. (go figure) Much to the chagrin of the spontaneous generation scientists (and I use the word “scientist” quite liberally), the more enlightened scientists said, a bit smugly, “See, when the flies are prevented from entering the jar, the steak may begin rotting, but it never bore those nasty little maggots.
In Lucy Cooke’s delightful and amusing book, “The Truth About Animals,” she describes the recipe proposed by 17th-century Flemish chemist Jan Baptist van Helmont for the spontaneous generation of spiders and mice. To create an arachnid “Take one brick, make a deep hole, and fill with basil, cover with a second brick, and leave in the Sun. In a matter of days, fumes from the basil acting as a leavening agent, will have transformed the vegetable matter, filling your home with veritable scorpions.”
To get a mouse, Helmont suggests you place some wheat and water in a flask and cover it with the skirt of an “unclean woman,” and voila, after 21 days, you’ll have a small rodent companion.
Ok, enough of the preposterous antics of pseudo-scientists. Let’s move ahead to the experiment that was the death knell for the theory of spontaneous generation.
In 1859, the French Academy of Scientists pitted spontaneous generation proponent Félix Pouchet against the young, relatively unknown chemist Louis Pasteur in a series of debates and experiments to prove or disprove that life for some species arises from non-living matter.
The experiments involved placing boiled broth in a flask. Pouchet asserts that the broth becomes turgid after a certain amount of time, indicating, he believed, that microorganisms had formed in the broth. Pouchet was correct in asserting that microorganisms were in the broth, but incorrect in explaining how they entered the broth.
Pasteur, on the other hand, states that microorganisms are present in the air, and Pouchet’s open flask allows airborne microbes to enter and proliferate in the broth. For his experiment, Pasteur designed a new type of flask with a curving neck, called a swan-neck beaker. His broth remains clear and microbe-free for days because the design prevented the microbes from entering the flask.
Pasteur officially wins the debate, the spontaneous generation theory is put to bed, and Pasteur gets 500 francs for his efforts.
Charles Darwin’s book, “The Origin of Species,” was first published in November 1859. In this landmark book, he introduces the theory of evolution, which many still regard as a challenge to the biblical account of the Genesis creation narrative. However, on page 484 near the end of the book, we find a single sentence that hints at a divine origin of life; “Therefore I should infer that probably all the organic beings which have ever lived on this earth have descended from some one primordial form into which life was first breathed.” What are we to make of this statement? I leave the answer up to you, reader.
Ironically, science has come full circle in its understanding of the theory of abiogenesis, which pertains to the origin of life on Earth. You have undoubtedly heard of the term “primordial soup.” This theory proposes that forces such as volcanoes and lightning act upon non-living matter, creating amino acids, which further evolve into more complex molecules, eventually leading to the emergence of simple life forms.
So far, the primordial soup theory and similar theories have not yielded the results hoped for. I must confess that I find it hard to comprehend how life as we know it can arise from the matrix of rock and water that made up the Earth before any form of life existed.
A few years ago, there were rumblings from the theoretical physics community that we may be fast approaching our limits in fully understanding our universe, both on a large scale and at an exceedingly tiny level. If this turns out to be the case, much of our surrounding reality will remain a mystery.
In closing, one of my favorite songs speaks to the question of where we came from and where we go when it’s all over. Iris Dement’s humorous anthem to life and death, “Let the Mystery Be,” presents an alternative perspective on the big question. I’m with you all the way on this, Iris Dement, and anyway, who doesn’t enjoy a good mystery?
Until next time,
Ken Springer
ken1949bongo@gmail.com
Citations:
Undiscovered, episode 25
Science Friday, WNYC
Ridiculous History, Part One the Debunked Theory of Spontaneous Generation
Society for Industrial microbiology and biotechnology, June 2019
