A Method of Staining Thin Sections with Lead Hydroxide for Precipitate-free Sections

Staining of thin sections results in greater contrast which facilitates focusing and the observation of fine structure. Lead hydroxide, as suggested by Watson (1), has become increasingly popular as a stain for electron microscopy. However, when lead hydroxide is exposed to the carbon dioxide of air, lead carbonate forms and is deposited on the sections as fine, needle-like crystals, large amorphous or polygonal precipitates, or small granules. In order to prevent the stain from coming in contact with air, Peachey (2) used a plastic, air-free syringe as a receptacle for the stain and as a mechanism for staining sections. The cover of the syringe was filled with a carbon dioxide trap consisting of sodium hydroxide, anhydrous calcium chloride, and cotton. Parsons and Darden (3) designed a