fuchsin

n any one of a group of reddish to purplish dyes used in staining bacteria for microscopic observation and capable of killing various disease-causing microorganisms. Acid fuchsin (acid magenta) is a mixture of sulphonated fuchsins; basic fuchsin (basic magenta) and new (trimethyl) fuchsin are basic histological dyes (basic fuchsin is also an antifungal agent).