Bio

Aristóteles (384-322 a.C.)

384

He proposed the theory of spontaneous generation. He believed that certain life forms, such as insects, could arise from inorganic or decaying matter under the right conditions.

Francesco Redi

1668

Experiment: Meat in jars. He placed meat in three jars: one open, one covered with gauze and one closed. Only in the open jar did larvae appear, which showed that insects did not arise spontaneously, but from eggs laid by other insects.

John Needham

1745

Experiment: Boiled beef broth. He boiled beef broth and sealed it, but observed microbial growth, wrongly concluding that these microorganisms arose spontaneously.

Lazzaro Spallanzani

1768

Experiment: Needham's review. He boiled the broth for longer and sealed the jars tightly. No microbial growth occurred, suggesting that the microorganisms came from the air, not from spontaneous generation.

Louis Pasteur

1861

Experiment: Swan-neck flasks.
Description: He demonstrated that air contains microorganisms by boiling broths in flasks with swan-necks, which prevented the entry of airborne particles. The broths remained sterile as long as the neck remained intact, definitively refuting spontaneous generation.