Cell Division
Year of Discovery: 1882
What Is It? The process by which chromosomes split so that cells can divide to
produce new cells.
Who Discovered It? Walther Flemming
Why Is This One of the 100 Greatest?
Chromosomes carry genes that hold the blueprints for building, operating, and maintaining the cells of your body. Genetics and heredity research could not advance until these
physical structures inside the nucleus of each cell had been discovered and studied. Our basic understanding of biology also depends, in part, on our knowledge of how cells divide,
replicating themselves countless times over the course of an organism’s life.
Both of these key concepts were discovered during one experiment carried out by
Walther Flemming. His discoveries form part of the basic foundation of modern biological
sciences. Much of what we know today about cell division (called mitosis) originated with
Flemming’s discoveries.
How Was It Discovered?
For most of the nineteenth century, studies of cells, cell functions, and cell structure
through the microscope were hampered because cell walls and all of their internal parts
were translucent to transparent. No matter how good the microscope was, these inner structures were seen only as vague grey-on-grey shapes. It was difficult—if not impossible—to
make out any detail.
So scientists stained the cells with dyes, hoping to make the cell parts more visible.
However, all dyes killed the cells. But there was no other way and, hopefully, the dye would
combine with some intracellular structures and not with others so that a few would stand out
and be easily studied through the microscope. Most dyes, however, didn’t work. They
smeared the whole cell with dark color and masked the very structures they were suppos V@?F?&WfV???v?F?W"f?V???rv2&?&????C2??66?6V?&W&r?vW&?????RG&??VB2F?7F? ??BFVv?BBV??fW'6?F?W2g&???s2?BF?RvR?b3?V?F???R?vRc"???R6??VB???6V?`???F??7B?B7V6???VB??F?R?7&?66??27GVG??b6V??2?? ???