ABSTRACT
The most commonly used stains for electron microscopy are salts of the heavy metal osmium. Studying the cell and its contents in the electron microscope not only required its modification but its complete transformation. Fixation seeks to join the contents of the cell and the object more generally to each other, to, in essence, make them immobile by making them into a single object. The dream of an accurate description of the cell’s anatomy remains unrequited. The linkage occurs at the molecular level and, for most “fixatives,” is the result of the formation of chemical bonds between the cells’s various parts. In the light microscope, this is thought to have little to no bearing on what is observed, because the objects are being examined at relatively low magnification, far away from the molecular level where the bonding occurs.
