FRANCESCO REDI (1626-1697)
Francesco Redi was an Italian poet, biologist, physician and naturalist who founded experimental biology. Redi was the first scientist to challenge the theory of spontaneous generation (abiogenesis) by demonstrating that living organisms did not actually originate from non-living things. He is also often regarded as the father of modern parasitology because of his discovery of many parasites such as Ascaris lumbricoides, Fasciola hepatica and helminthes (intestinal worms) to mention but a few. Redi developed a scientific experiment to test the spontaneous creation of maggots from fresh meats using two jars (one of the jars was left open while the other jar was closed). He challenged the concept of abiogenesis by showing that maggots on decaying meat came from fly eggs deposited on the meat and not from the meat itself.
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Redi explained that flies land on exposed meat and lay their eggs which eventually hatch to produce maggots. Redi performed series of experiments in the early 1670’s in which he covered jars of meat with fine lace that prevented the entry of flies into the jars. Because the meat was covered, no maggots were produced, and this led Francesco Redi to drop the notion of spontaneous generation. Francesco Redi successfully challenged and refuted the theory of spontaneous generation through his work on maggot and flies, in which he showed that maggots on meat came from egg flies. Though his work was known as at the time, the ideaof spontaneous generation was not dropped as other scientist like John Needham continued from where he stopped to unravel the mystery behind it.
GIROLAMO FRACASTORO (1478-1553)
Girolamo Fracastoro was an Italian poet, scholar and scientist who also had specialties in several areas such as geography, mathematics and astronomy. While the issue of spontaneous generation lasted as at the time, some other scientist like Girolamo Fracastoro was interested about the transmission of the disease caused by these microorganisms. Girolamo Fracastoro proposed that epidemic diseases are caused by transferable tiny particles or spores (that does not necessarily need to be living entities but chemicals) that could transmit infection by direct or indirect contact or even without contact over long distances.
His work led to the use of the term “fomites” in medicine, a phrase he used to describe inanimate things like clothes and linen, which although not themselves infected or polluted, but can nevertheless promote the essential seeds of the contagion and thus cause infection in humans who come in contact with these infected clothes. Contagion here refers to a contagious or infectious disease. Fomites are non-living vehicles (for example, water, clothes, tables, chairs and food) that help to transmit infectious agents and/or diseases to susceptible human or animal hosts. Girolamo had the concept that “contagion is an infection that passes from one thing to another”, and he recognized three phases or forms of this passage as contact, air and lifeless objects or fomites.
His idea received credibility that microorganisms were the substance of contagion, and his theory remained influential for nearly three centuries, before being displaced by germ theory of disease which states that diseases are caused by particular microorganism. Contagion was the term used by Girolamo when referring to pathogenic microorganisms or infectious diseases.
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