-
Francesco Redi
Francesco Redi ( 1626 - 1697 ) was an Italian physician, naturalist, biologist, and poet.
He was the first person to challenge the theory of spontaneous generation by demonstrating that maggots come from eggs of flies. -
Redi's experiment
Redi's experiment consisted on placing pieces of meat in 4 jars, half of them with an open lid and half of them with a closed one. Flies only apeared on the jars with and open lid.
Redi's hypothesis was that flies laid eggs on the rotting meat, and maggots developed from those eggs. The purpose of his experiment was to test this same principle of spontaneous generation. -
John Needham
John Needham (1713 - 1781) was an english biologist and Roman catholic priest.
He conducted many experiments that supported the theory of spontaneous generation. -
Lazzaro Spallanzini
Lazzaro Spallanzini ( 1729 - 1799 ) was an italian catholic priest, biologist and physiologist who made lots of advances in the field of animal reproduction and animal echolocation.
His experiments disproved spontaneous generation. -
Needham's experiment
Needham's experiment involves briefly heating broth to its boiling point, so all the microorganisms are killed, pouring it into flasks and once it's cooled down, sealing the flasks. After some time, he could observe moving organisms in the flasks, supporting the theory of spontaneous generation. -
Spallanzini's counteer to the theory
Spallanzini disagreed with Needham so he repeated the experiment and saw no trace of life, he then concluded saying that the microorganisms came from polluted air -
Louis Pasteur
Louis Pasteur ( 1822 - 1895 ) was a French microbiologist and chemist known for his discoveries of the principles of vaccination, microbial fermentation and pasteurization (named after him). -
Pasteur's experiment to finally disprove spontaneous generation
Louis Pasteur designed a procedure to test whether sterile nutrient broth could spontaneously generate microbial life. He set up two experiments. In both, Pasteur added broth to flasks, bent the necks of the flasks into S shapes, and then boiled the broth to kill any existing microbes. Pasteur broke the necks of some flasks and left some intact.
He could observe that the broken ones became cloudy and the other ones didn't. Without the broth being poluted, no life arose. Proving his point.