A Technique for the Simultaneous Dirt-free Lead Staining of Several Electron Microscope Grids of Thin Sections

The staining of thin sections of Osmium tetroxide (OsO4)-fixed biological materials with the lead hydroxide preparat ion of Watson (5) or with semisaturated solutions of lead subacetate (1) represents a considerable advance in electron microscope technique. The contrast of the image viewed in the electron microscope is so far enhanced that accurate focusing is now possible at appreciably higher magnifications. The contrast and detail visible in the micrograph also appears much improved, without the introduction of obvious artifacts. For routine work, a serious handicap is the formation of a precipitate of lead carbonate over a large proport ion of the section area. The method described by Peachey (4) considerably reduces this precipitate but allows only one grid to be stained per syringe. In the method to be described, as many as six grids can be stained simultaneously without any precipitation of lead carbonate.