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Scorpions
In the 17th century there was a recipe for the explanation of the spontaneous generation. The recipe was “Carve an indentation in a brick, fill it with crushed basil, and cover the brick with another. You will find that within a few days, that the basil transformed into veritable scorpions.” The reality of this experiment was that the basil has an especial aroma, so the scorpions went there to eat it, and then, lay some eggs, and from these eggs appeared new scorpions. -
Redi's experiment
In 1668 the italian physician and poet made the first serious attack to the spontaneous generation theory. In 17th they all thought that the maggots come spontaneously from the rotting meat. So Redi did the following experiment. He took a glass and put some meat inside of it, and then left it then, there were a kot of flies and maggots, later, he took another glass and put more meat, but this time he thightly sealed it. And the flies couldn't enter to the glass, so there were no maggots. -
Needham's experiment
John Needham, an English clergyman, he made an experiment to demonstrate that the spontaneous generation is true. He boiled some broth to its boiling point to kill all the organisms inside it, an then he poured the broth into flasks, and when it cold down, he sealed it. After some time, there were microorganism growing from the broth. -
Spallanzani's experiment
Lazzaro Spallanzani did not agree with Redi's conclusion, so he made hundreds of experiments with broth, and he arrived to a conclusion. He made the following experiment. He took a flask with broth too, he sealed it before, and then he boiled it. Now the flask is sterilized. So when the broth cold down, there where no microorganism, but when you open the flask, they start to appear. He concluded that the microorganism where on the air. -
Pasteur's experiment
So basically, he took some flasks with an S-curved neck, and decided to sterilize it, and then leave it opened. He left it one year, but there where not microorganisms inside the flask, all were resting in the curved part of the neck. But then he broke the neck, and within seconds, the microorganisms began to appear. He concluded that the contamination come from the air.