AbstractFresh pullet eggs (White Leghorn strain) were incubated from 19–26 hours. Blastoderms were fixed in ovo by selected fixatives of various tonicities, postfixed in 2% OsO4, dehydrated in acetone, critical‐point‐dried in liquid CO2, coated with palladium‐gold and observed in a Cambridge S4 scanning electron microscope.Shrunken cells with intracellular yolk granules embossed on the surface are produced by the strongly hypertonic Karnovsky's fixer (Final: 2010 mOsm). Embryos fixed with modified Karnovsky's fixer (Final: 373 mOsm) possess surfaces with irregular microappendages. Swollen cells with few microappendages are obsrved when embryos are fixed in a hypotonic environment (Final: 250 mOsm or less). Ideal fixatives preserve a relatively flat surface, with cells bordered by smooth surface microappendages. For adequate SEM fixation, fixative vehicle should be approximately isotanic for tissue, with aldehyde (2% or less) added to