Contributions of Electron Microscopy to Biology and Medicine

Abstract

In the development of the biological and medical sciences, morphology has traditionally served as pacemaker, from the Renaissance on when Vesalius founded Anatomy as a science.The invention of the microscope brought observation into the range of invisible structures. This ended around the middle of the last century when the cell was discovered as the fundamental unit of living matter, and also as the site of disease, causing “numoral” pathology to be replaced by cellular pathology (Virchow).At the same time, microscopic methods had reached their limit. The chemical revolution stepped in and biochemistry became the pacemaker in biology and medicine; we seemed to move back to “humoral pathology”.When electron microscopy was applied in biological studies after 1950 a new “invisible world” was discovered: the power of morphological observation was extended to the molecular level. Membranes were discovered as boundaries of the cell and as barriers between compartments: cell function was seen as a highly ordered process. Step by step with ever more refined techniques, cellular organization was unravelled. Today's picture is that of a totally ordered cell with precise relationships to its neighbors. The structure of bacteria and viruses and the pattern of their interaction with cells and tissues was revealed. The diversity of cells became reduced to variations over a common basic scheme.