Robert Koch • Tuberculosis Lab
Identifying Mycobacterium tuberculosis with Acid-Fast Staining
Use the buttons to apply an acid-fast stain and watch rod-shaped bacteria that keep the red dye stand out. This models how Koch and others linked a specific bacterium to tuberculosis.
Short steps, clear visuals
Follow: stain → decolorize → counterstain.
Acid-fast rods (M. tuberculosis-like)
Non–acid-fast bacteria
Counterstained background cells
Step:
Unstained smear
Start with a mixed smear. After carbol fuchsin, all rods look red. After acid alcohol, only acid-fast rods keep the red dye. After methylene blue, other cells turn blue, while acid-fast rods stay bright red.