Disproving Spontaneous Generation
It was a commonly held belief in Ancient Rome, during the MiddleAges, and even until the late nineteenth century that spontaneousgeneration, or the sudden generation of complex life from nonliving matter,existed. (Evers, 1999) Scientists began to question this theory as earlyas the second half of the seventeenth century, but it was not until almost200 years later that Louis Pasteur definitively disproved spontaneousgeneration and changed the course of scientific thought. While it is stilldebated whether any forms of Abiogenesis, or the generation of even simpleor microscopic life from nonliving matter, could be possible (Wilkins,2004), it is certain that spontaneous generation involving complex life The first recorded Westerner to suggest spontaneous generation wasAnaximander, a philosopher from the BC 600's and 500's. His pupil,Anaximenes, wrote that air imparted life, motion, and thought. Xenophanesand Parmenides thought that plants and animals would spontaneously
(Wilkins, 2004) Aristotle, in the times of AncientGreece, believed that life was the result of the ether, a substance whichexisted only in the heavens, combining with the pneuma, or the animatingforce or soul, and that if the pneuma was present, it would be possible forlife to come from nonliving material. (Evers, 1999) Finally, in 1859 Louis Pasteur would settle the debate for mostscientific minds. LazzaroSpallanzani suggested that the microorganisms had entered through the airthat remained in the flask before sealing it, and he used a vacuum to showthat no microorganisms would appear in the broth if the air was removed. The modern definition of abiogenesis has beenremoved from the concept of spontaneous generation, which postulated theformation of complex organisms from nonliving matter, and has come torepresent instead the theory of "primordial archebiosis" which is a kind ofevolution theory. " (Evers, 1999) Spontaneous generation is not possible. Some argued, however, that this simply proved that air was necessary forspontaneous generation, as had been previously argued. Whenmaggots appears only on the meat which was exposed to the air, andtherefore to flies, his theory that maggots came from the eggs of flies andnot from the rotting meat itself was more or less proven. Building on the ideas of both Needham and Spallanzani,he boiled meat broth in a flask to kill the microorganisms. Nomicroorganisms appeared in the broth. (Wilkins, 2004) In 1668, Francesco Redi, a physician and poet, attacked the idea ofspontaneous generation. Empedocles wrote in the BC 400's that spontaneousgeneration is possible if there are the correct combinations of parts ofanimals to rise. When the flask was tilted, however,so that the broth reached the bend in the neck of the flask, where themicroorganisms in the air had settled, then microorganisms did appear inthe broth. When new microorganisms appeared in the broth, heclaimed them to be the result of spontaneous generation. "Pasteur had both refuted the theory of spontaneous generationand convincingly demonstrated that microorganisms are everywhere - even inthe air.
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