A modified procedure for lead staining of thin sections is described. Lead hydroxide, though widely used, is unstable and leads to contamination. To address this, a new solution was developed using sodium hydroxide and potassium sodium tartrate. This solution is stable and effective for staining, without the contamination issues of lead hydroxide. The new solution is prepared by dissolving 12.5 g of sodium hydroxide and 5.0 g of potassium sodium tartrate in 50.0 ml of water. This stock solution is diluted to 100 ml with distilled water, heated, and 1 g of commercial lead hydroxide is added. The solution is then filtered and has a pH of about 12.3. If lead hydroxide is not available, it can be prepared from lead acetate and sodium hydroxide. The resulting solution is clear and stable. The new staining solution is effective for staining thin sections within 5-20 minutes, is stable for several weeks, and does not contaminate the sections. It can be stored in a glass bottle with a dropper. The staining properties are similar to those of the original Watson formula, and the solution provides adequate contrast for electron microscopy. The new stain allows for the clear identification of all known cell organelles and avoids contamination. The procedure was tested against other lead stains, and the results showed that the new solution is effective and stable. The study was published in 1961.A modified procedure for lead staining of thin sections is described. Lead hydroxide, though widely used, is unstable and leads to contamination. To address this, a new solution was developed using sodium hydroxide and potassium sodium tartrate. This solution is stable and effective for staining, without the contamination issues of lead hydroxide. The new solution is prepared by dissolving 12.5 g of sodium hydroxide and 5.0 g of potassium sodium tartrate in 50.0 ml of water. This stock solution is diluted to 100 ml with distilled water, heated, and 1 g of commercial lead hydroxide is added. The solution is then filtered and has a pH of about 12.3. If lead hydroxide is not available, it can be prepared from lead acetate and sodium hydroxide. The resulting solution is clear and stable. The new staining solution is effective for staining thin sections within 5-20 minutes, is stable for several weeks, and does not contaminate the sections. It can be stored in a glass bottle with a dropper. The staining properties are similar to those of the original Watson formula, and the solution provides adequate contrast for electron microscopy. The new stain allows for the clear identification of all known cell organelles and avoids contamination. The procedure was tested against other lead stains, and the results showed that the new solution is effective and stable. The study was published in 1961.