We explain what the Spontaneous Generation Theory is, what thinkers supported it and how it was refuted.
According to this theory, living things could arise from decomposing matter.What is the theory of spontaneous generation?
The Theory of Spontaneous Generation was the name given to the belief that certain forms of animal and plant life arose automatically, spontaneously, from the organic material, the inorganic material or some combination of both.
This theory was in force for many centuries, from the Antiquity. Although it is a hypothesis that could never be scientifically proven, many believed to verify it by means of the observation direct.
Aristotle, the Greek philosopher, believed in this theory. It was also accepted and supported by thinkers of the seventeenth and eighteenth centuries such as Sir Francis Bacon, René Descartes and Isaac Newton, who were unaware of the world of the microbiology. It applied to small creatures kept by pests or parasites, such as flies, lice, ticks, and even mice.
The belief was that if the correct items (say: sweaty underwear and wheat) were left in a container, some kind of animals (say: mice).
This theory of the origin of life did not contradict conventional reproduction, since the creatures obtained by spontaneous generation were as perfect and identical as those born of the sexual reproduction.
In this way, it could be sustained that in the decomposed meat, the excrement or the entrails of the human being, different forms of life were given by spontaneous generation, instead of thinking that they had somehow gotten there.
Refutation of the Theory
The Spontaneous Generation Theory was refuted through three specific experiments:
- Redi's experiment. Carried out by Francesco Redi, an Italian physician, who doubted that insects could arise spontaneously from putrefaction, and assumed that at some point some adult insect must lay eggs or larvae on the matter decomposing. To verify this, he placed three pieces of meat in three different containers: one of them open and the other two sealed with gauze that would allow the entry of the air to the bottle but not from the adult flies. After time, there were worms in the exposed meat and not in the sealed ones, although they did find fly eggs on the gauze.
- The Spallanzani experiment. Later developed by the Catholic priest and naturalist Lázaro Spallanzani, it was a kind of prelude to pasteurization. The Italian placed meat broth in two containers, after having heated them to a temperature to kill existing microorganisms and to have hermetically sealed in the container. Thus he demonstrated that microorganisms They do not arise spontaneously from matter, but come from other microorganisms.
- Pasteur's experiment. Developed by the French Louis Pasteur, father of the technique of food preservation known as pasteurization, consisted of the introduction of meat broth into two distillation bottles with a long and curved mouth (in the shape of an “S), which becomes thinner as it rises. The shape of the tube allowed air to enter, but made the microorganisms stay in the lower part of the container, without accessing the meat. Thus, he heated the broth until it was sterilized and simply waited: after several days, there were no signs of decomposition, after which Pasteur proceeded to cut the mouth of the container and there, after a short time, decomposition did occur, thus demonstrating that the microorganisms came from other microorganisms and that, in general, all life comes from another form of life that precedes it.