Francesco Redi discovered that maggots do not spontaneously generate from non-living material but come from the eggs of flies. His experiments contributed to disproving the theory of spontaneous generation.
Redi helped disprove the idea of spontaneous generation by conducting experiments in which he sealed a jar with meat inside, placed netting over a second jar of meat and left a third jar open. The jar that was left open developed maggots. Flies were observed entering this jar and laying eggs on the meat. The sealed jar contained no maggots because it did not allow flies access to the meat to lay eggs. The jar with netting over it, even though it allowed air access to the meat, did not develop maggots because flies were unable to enter.