The most relevant scientists

Francesco Redi description

1626

He was an Italian physician and poet who demonstrated that the presence of maggots in putrefying meat does not result from spontaneous generation but from eggs laid on the meat by flies. He read in the book on generation by William Harvey a speculation that vermin such as insects, worms, and frogs do not arise spontaneously, as was then commonly believed, but from seeds or eggs too small to be seen.

Redi's experiment (Francesco Redi)

1668

He had just one goal, that was to determine whether flesh would naturally produce maggots. Then, he repeated the experiment under various settings in three different samples.
Results:
- Maggots were visible in the first situation, where the meat was in open jars with flies around it.
- Maggots didn't show up in the second situation, where the meat was contained in a securely closed jar.
- No maggots also appeared in the final condition, where the flesh was coated with a fine mesh.

John Needham description

1722

John Turberville Needham, more commonly known as John Needham, was an English naturalist and Roman Catholic cleric. He was the first clergyman to be elected to the Royal Society of London. He is also noted for his theory of spontaneous generation and the scientific evidence he had presented to support it.

Lazzaro Spallanzani description

1729

Italian physiologist who made important contributions to the experimental study of bodily functions and animal reproduction. His investigations into the development of microscopic life in nutrient culture solutions paved the way for the research of Louis Pasteur. Spallanzani was the son of a distinguished lawyer. He attended the Jesuit college at Reggio, where he received a sound education in the classics and philosophy.

Needham's experiment (John Needham)

1745

In his experiment, Needham heated "water" in a covered flask. According to his logic, boiling would get rid of any existing microorganisms in the liquid and closing the flask would keep out any new ones. But when he later examined the liquid, he found bacteria on it.
Needham's experiment supports the idea of spontaneous genesis because microbes had grown in the broth on their own. However, another biologist, Lazzaro Spallanzani, disagreed with his conclusions.

Spallanzani's experiment (Lazzaro Spallanzani)

1765

Lazzaro Spallanzani, an Italian scientist, repeated Needham's experiment to show that they didn't emerge on their own. In order to prove that the organisms started in the air rather than spontaneously entering the liquid, he demonstrated that sterilized soup in tightly closed flasks did not encourage microbial development unless exposed to air.
This proves that John Needham's experiment employed flasks that were incorrectly sealed.

Louis Pasteur description

1822

Louis Pasteur was a French chemist and microbiologist who was one of the most important founders of medical microbiology. Pasteur’s contributions to science, technology, and medicine are nearly without precedent. He is best known for inventing the process that bears his name, pasteurization. Pasteurization kills microbes and prevents spoilage in beer, milk, and other goods. In his work with silkworms, Pasteur developed practices that are still used today for preventing disease in silkworm eggs.

Pasteur's experiment (Louis Pasteur)

1859

Louis Pasteur's experiment involved cooking some soup and storing it in flasks with long, curved necks to keep out dust and bacteria. To get rid of any bacteria, he cooked the soup, and he noticed that nothing sprouted. The swan-necked flask provided evidence that no "air" microorganisms could enter the sterilized soup, demonstrating that germs do not arise spontaneously but rather from pre-existing bacteria.