EXPERIMENTS have been made with five specimens of methylene blue as a vital stain for the spermatocytes of Helix aspersa. The specimens were an old German ‘polychrome methylene blue', and four ...

Examples include methylene blue, basic fuchsin, and crystal violet. These dyes directly bind to and stain the negatively charged surface of bacterial cells. Negative, anionic, or acidic dyes: contain ...