This photograph depicts the colonial morphology displayed by Gram-negative, Francisella tularensis bacteria, which were grown on a medium of modified Thayer-Martin (MTM) agar, for a 24-hour time period, at a temperature of 37°C. See PHIL 12445, for a closer view of these bacterial colonies. Take a look at PHIL 12446, which depicts the appearance of F. tularensis colonies grown on the same medium, and at the same temperature, but for twice the time (48hr). Also see PHIL 12447, for the appearance of bacterial colonies, again, grown on the same medium, and at the same temperature, but for three-times the time period (72hr). This bacterium is both an animal, and a human pathogen, and is responsible for causing the disease known as tularemia.