1 Anton van Leeuwenhoek in 1674, first identified living cells in pond water.
2 In 1831, a scientist named Robert Brown discovered the cell nucleus.
3 J. E. Purkinje in the year 1839 coined the term ‘protoplasm’ for the fluid substance of the cell.
4 Mathias Schleiden and Theodore Schwann in 1838 proposed the Cell Theory.