Phagocytosis of Clostridium bacteria. Transmission electron micrograph (TEM) of a section through two Clostridium sp. bacteria (orangee circles) which have been engulfed by a macrophage (green). These bacteria are commonly found in wound infections, and are a major cause of gas gangrene (tissue death through infection). The macrophage has extended its body towards and around the bacteria, capturing and engulfing them in a process called phagocytosis. Macrophages are part of the immune system which keeps the body free of invading organisms. These bacteria will be chemically destroyed by enzymes. Magnification: x15,000 when printed at 10 centimetres tall.