Rudolf Virchow's major contribution to cell theory was the formulation and popularization of the principle omnis cellula e cellula , meaning "every cell stems from another cell." Published in 1855, this concept established that cells do not arise spontaneously but only from the division of pre- existing cells, thereby rejecting the earlier notion of spontaneous generation

. Building on the work of Robert Remak, who had earlier demonstrated cell division, Virchow integrated this idea into cell theory and extended it to the understanding of disease. He founded the field of cellular pathology by showing that diseases result from changes in cells, emphasizing that pathological processes occur at the cellular level. This insight allowed for more precise diagnosis and treatment of diseases by focusing on cellular abnormalities rather than just symptoms

. Virchow's work also challenged the doctrine of vitalism by establishing cells as independent living units that make up organisms, which was a significant advancement in biology. His contributions laid the groundwork for modern cellular biology and pathology, transforming medical science by linking cellular changes directly to health and disease

. In summary, Virchow's key contributions to cell theory include:

• The principle that all cells arise from pre-existing cells (omnis cellula e cellula).
• The foundation of cellular pathology, linking disease to cellular changes.
• Advancing the understanding of cells as fundamental living units, which helped refute spontaneous generation and vitalism