False-colour transmission electron micrograph of the Gram-negative bacteria, Neisseria meningitis (meningococcus), causative agent of cerebrospinal fever (spotted fever) & bacterial meningitis in humans. A spherical type of bacteria (cocci), they are commonly found growing in pairs or clumps. They are transmitted from person to person in droplets of mucus from a patient or carrier. Magnification: x13, 225 at 35mm size.