The Spallanzani's contributions

The first Spallanzani's jobs concern the "animaletti" (protozoa) of the infusions. These had been discovered by Leeuwenhoek,a Dutch who observed the water of a sweet lake with the first microscope, around 1674.

The problem that it rose was understood from where they came and as they were formed.

In the 18th century, Reamur resumed the Redi's reasonings and he found absurd that bugs and other living could be born from the mud or meat in putrefaction, but unfortunately the idea of the spontaneous generation of microscopical living was again diffused.

Spallanzani began to be interested to the microscopical "animaletti" obtained in the infusions of seeds from other scientists.
He prepared several seed-infusions that he put in closed containers and he made them to boil for an hour holding them dipped in water.

The infusions remained limpid.

Spallanzani, then, pierced the containers after the boiling. He noticed that after some days the infusions became turbid and popolous of germs.
These experiments were published in the 1765.

Spallanzani made also some experiences on the survival of these ' animaletti' with the cold. It observed that to -6° some they died and he wondered if indeed the cold could to kill them and not the freezing of the water.