Methenamine Silver Stain.

This micrograph depicts histopathologic changes associated with Histoplasmosis of the lung using methenamine silver stain, 1965. Here the yeast forms of H. capsulatum are shown. This organism which grows in soil or material contaminated with bat or bird droppings, becomes airborne when contaminated soil is disturbed, and breathing the spores causes infection. Image courtesy CDC/Dr. Martin Hicklin. (Photo by Smith Collection/Gado/Getty Images).