Spallanzani's Amphibians

Spallanzani's experiments with amphibians demonstrated that life arises only from existing life, challenging the idea of spontaneous generation. He showed that when he sealed vital fluids inside a vessel, amphibian eggs and embryos failed to develop unless exposed to fresh, life-carrying air. This indicated that air contains the vital force necessary for life to begin, and that life did not spontaneously appear from non-living matter. His work was crucial in advancing the understanding of reproduction and the requirements for life to develop, emphasizing the importance of air and environmental conditions in biological development.