What experiments supported the idea that cells arise from cells?

Several scientific experiments supported the concept that cells come only from pre-existing cells. One of the most famous was conducted by Louis Pasteur in 1861. Pasteur used a swan-neck flask containing nutrient broth. He boiled the broth to kill any microorganisms, then left the flask open to air. 

Because of the curved neck, dust and microbes could not reach the broth, and no life appeared. However, when the neck was broken, microbes grew rapidly. This experiment disproved spontaneous generation and supported the view that life comes from life.

In cellular biology, microscopic observations also provided evidence. Scientists observed cell division (mitosis) under microscopes, seeing how one cell splits into two daughter cells. These visual proofs confirmed Virchow’s claim that new cells form by division of existing ones.

Together, these experiments established that cells cannot originate spontaneously. They form through a biological process that copies existing structures and genetic material — a key principle that underpins modern biology, medicine, and genetics.