who expanded cell theory by suggesting that all cells arise from preexisting cells
Cell theory Schleiden's theory of free cell formation through crystallization was refuted in the 1850s by Robert Remak, Rudolf Virchow, and Albert Kolliker.[7] In 1855, Rudolf Virchow added the third tenet to cell theory. In Latin, this tenet states Omnis cellula e cellula.[10] This translated to:
Protoplasm The word "protoplasm" comes from the Greek protos for first, and plasma for thing formed, and was originally used in religious contexts.[39] It was used in 1839 by J. E. Purkinje for the material of the animal embryo.[12][40] Later, in 1846 Hugo von Mohl redefined the term (also named as Primordialschlauch, "primordial utricle") to refer to the "tough, slimy, granular, semi-fluid" substance within plant cells, to distinguish this from the cell wall and the cell sap (Zellsaft) within the vacuole.[13][41][42] Thomas Huxley (1869) later referred to it as the "physical basis of life" and considered that the property of life resulted from the distribution of molecules within this substance.[43] The protoplasm became an "epistemic thing".[44] Its composition, however, was mysterious and there was much controversy over what sort of substance it was.[45]