The supposed development of living organisms from nonliving matter. Redi designed an experiment to determine what caused the sudden appearance of maggots. In his experiment, the manipulated variable was the presence of absence of the gauze covering. The results of this experiment helped disprove the hypothesis of spontaneous generation. Needham: claimed that spontaneous generation could occur under the right conditions. To prove his claim, he sealed he sealed a bottle of gravy and heated it. He claimed that the heat had killed any living things that might be in the gravy. After several days he examined the contents of the bottle and found it swarming with activity. These little animals, he inferred, can only have come from the juice of the gravy.
Attacked Redi's work. Spallanzani experiment showed that microorganisms will not grow in boiled gravy that has been sealed but will grow in boiled gravy that is left open to the air. improved on needhams experiment. Pasteur experiment showed that boiled broth would remain free of microorganisms even if air was allowed in, as long as dust and other particles were kept out. Hypothesis of spontaneous generation was not correct. He showed that all living things come from other living things. pasteur also began to uncover the very nature of infectious diseases, showing that they were the result of microorganisms entering the body. He is considered one of biologys most remarkable problem solvers.