Francesco Redi was a 17th century scientist who was known for creating the idea of controlled experiments and disproving the theory of spontaneous generation. Essentially, Redi proved that maggots cannot spontaneously generate from meat. Redi used the idea of a control (placebo) condition while carrying out the experiments with maggots. He placed 'meat' and inanimate objects in the following conditions; one jar open (control); one jar covered with netting, and one jar sealed from the outside to see if maggot would spontaneously generate from the meat or inanimate objects. He found that the open jar of meat attracted flies that laid eggs and maggots developed; the jar covered with netting had flies lay eggs on the top of the netting and the sealed jar did not attract flies and therefore no maggots. This 'controlled' experiment allowed Redi to refute the idea that life is formed from inanimate objects (meat).