Abstract
Small volumes of suboptimal particle concentrations for electron microscopy may easily provide at least the required 3.4 × 107 particles per cubic centimeter for this purpose when concentrated 10 to 1000-fold at an aqueous-air interface. As a result, ascending droplets of microorganisms derived from bursting bubbles were adsorbed to an Inverted agar surface strategically positioned above the reaction vessel. The agar surface was subsequently pseudoreplicated in a solution of uranyl-magnesium acetate for electron microscopic examination and quantitation.