First use of osmium, whole mount EM (Porter, 1945)
At one time, it was thought that a high speed microtome would be the solution! (Gessler and Fullam, 1946)
Glass knives (Latta and Hartmann, 1950)
The Porter Blum microtome (Porter and Blum 1953)
Diamond knives (Fernandez-Moran, 1953)
Epoxy resins - araldite (Glauert et al., 1956)
Potassium permanganate (Luft, 1956)
Lead citrate (Watson 1, 1958 - Watson 2, 1958)
Epoxy resins (Luft, 1961)
Glutaraldehyde (Sabatini, Bensch and Barrnett, 1963)

Historical review on embedding (Pease and Porter, 1981)
Nobel Prize lecture - "Development of the electron microscope and of electron microscopy" (Ruska, 1986)

uranyl acetate
horseradish peroxidase (Karnovsky, xxxx)
use of propylene oxide