In 1838-39 German botanist Jacob Schleiden, zoologist Theodor Schwann and later in 1855 Rudolf Virchow provided the theory of cells called cell theory. Cell theory is called Cell doctrine.
Fundamentals of Cell theory
1. All organisms are made up of cells.
2. Cell is the basic unit of life.
3. Cell is the structural, organizational and physiological unit of an organism.
4. It is the unit of inheritance.
5. New cells are formed from old cells.
6. All body functions take place inside cells.
7. The biological functions of the body depend on the functions of all cells.
8. All members of the same species have the same chemical nature of cells.
9. Cells contain the genetic information of organisms and are transmitted from cell to cell during cell division.
10. All biological functions of multicellular organisms are the sum of interactions of body cells.