Hypothesis of spontaneous generation suggested that life arises from non living things. There are number of experiments performed to prove this hypothesis, which does not hold true.
Pasteur carried out an experiment in which he took a round bottle flask having long curved neck. He placed boiled meat gravy into this flask. Air could enter into this flask, but the length of the neck did not allow the entry of dirt or micro organisms.
Hence, the gravy remained unspoiled (no growth of microorganisms), for quite a long period. When Pasteur broke the neck of the flask, gravy became turbid within few days due to the growth of micro organisms.
Thus, he concluded that life arises from the pre existing life and not from non living things.