False-colour scanning electron micrograph of spores of the large, rod-shaped bacteria Bacillus anthracis, the causative agent of anthrax in farm animals. The disease is transmitted to man by contact with infected animal hair, hides or excrement. The bacilli attack either the lungs, causing pneumonia (woolsorter's disease), or the skin, producing severe ulceration (malignant pustule). Anthrax is treated with antibiotics. In the body the bacteria appear singly or in pairs, but when cultured they link up to form chains, as seen here. Each bacterium produces a single spore, which then germinates into a new organism. Magnification: x2825 at 6x4.5 cm size.