The cell theory was proposed by two scientists- Botanist Theodor Schleiden (1838) and zoologist Matthias Schwann (1839).
Main postulates of the Cell Theory :
i) A cell is the smallest structural unit of all living things.
ii) A cell is the unit of function of all living things.
iii) All cells arise from pre – exiting cells.
Cell Theory is modified by Rudolf Virchow in 1958.