Warthin–Starry stain

The Warthin–Starry stain (WS) is a silver nitrate-based staining method (a silver stain) used in histology. It was first introduced in 1920 by American pathologists Aldred Scott Warthin (1866-1931) and Allen Chronister Starry (1890-1973), for the detection of spirochetes.[1][2] It has been considered the best stain for detection of spirochetes,[3] and is also used to stain Helicobacter pylori, Lawsonia intracellularis,[4] Microsporidia,[5][6] and particulates.[7]
WS stains organisms dark brown to black, and the background light golden brown/golden yellow.