Mitosis is the ordinary process of cell division resulting in the formation of two daughter cells, by which the body replaces dead cells. The daughter cells have identical diploid complements of chromosomes (46 in human somatic cells). Mitosis occurs in four main phases: prophase, metaphase, anaphase and telophase. The period between mitotic divisions is called interphase.
The Polish histologist Wacław Mayzel discovered mitosis in 1875 while observing the epithelium of a frog’s damaged cornea. He first fixed the specimens onto microscope slides with chromic or acetic acid along with colloidal gold and then stained them with carmine. He noticed some unusual cells around the damaged epithelium cells and noted his observations in his 1875 publication which included descriptions of different mitotic phases though he did not acknowledge them explicitly as a type of cell division. He did, however, note that what he observed was indeed cell and nuclear division. Here is a drawing of a mitotic stage (metaphase) based on a specimen prepared by Mayzel. He gave permission to the German biologist Walther Flemming to make and publish the drawing: