In 1838, Theodor Schwann and Matthias Schleiden were talking about their studies on cells. It suggests that when they found the similarities in their work and they immediately went to Schwann’s lab and looked at the slides. In the next year, they summarized their observation into three conclusion about cells. The first one is that the cell is the unit of structure, physiology, and organization in living things. The next one is that the cell retains a dual existence as a distinct entity and a building block in the construction of organism. The last one is that cells form by free-cell formation, similar to the formation of crystals.

We now know today that the last conclusion out of the three was incorrect because all cells only arise from pre-existing cells. The modern theory of Cell Theory includes six conclusions. The first one is that all known living things are made up of cells. The second one is that the cells are structural and functional unit of all living things. The third one is that all cells come from pre-existing cells by division. The fourth one is that cells contain hereditary information which is passed from cell to cell during cell division. The fifth one is that all cells are basically the same in chemical composition. The sixth one is that all energy flow of life occurs within cells..

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Theodor Schwann
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Matthias Schleiden