Methylene Blue staining of Bacillus anthracis showing the spores as dark blue with the vegetative cells staining red.

Source: CDC/ Courtesy of Larry Stauffer, Oregon State Public Health Laboratory, Public Health Image Library #1896.

Gram stain of Bacillus anthracis showing Gram-positive rods forming long filaments.

Source: CDC, Public Health Image Library #2105

Visualization of the capsule of Bacillus anthracis using an Indian ink stain.

CDC/ Courtesy of Larry Stauffer, Oregon State Public Health Laboratory

Colonial growth of Bacillus anthracis. When lifted by an inoculation loop, colonies, in this case on sheep blood agar, show a tenacity that allows them to be pulled up and stay upright with a texture similar to egg whites beaten to a stiff peak.

CDC/Courtesy of Larry Stauffer, Oregon State Public Health Laboratory, Public Health Image Library #1898

Encapsulation test for Bacillus anthracis. The difference in appearance of colonies on bicarbonate agar (smooth colonies on the left) and rough colonies (sheep blood agar on the right) is indicative of capsule formation.

Source: CDC/Dr. James Feeley, Public Health Image Library #1165

Rods of Bacillus anthracis in lung tissue (B&B stain)

Source: CDC/Dr. LaForce, Public Health Image Library #1789