Others also worked with the microscope following its acceptance as a scientific tool. Francesco Redi, an Italian physician and naturalist, used a microscope for observation of invertebrates, but is known for his work in disproving the theory of spontaneous generation. Redi managed to prove that flies did not spontaneously arise from rotting meat. He conducted controlled experiments and detailed observation of the fly life cycle in order to do so. Redi also worked in the description and illustration of parasites for both plants and animals.