Spallanzani disapproved the theory of abiogenesis (spontaneous generation)

Spallanzani's Experiment He experimented that animal and vegetable broths boiled for the several hours and soon after sealed, were never infested with microorganisms. From this experiment the concluded that, high temperature had killed all living organisms in the broths and without them life did not appear. When the broths were left exposed to air, it was soon invaded by microorganisms