Transmission electron micrograph of Clostridium botulinum bacteria, the cause of botulism food poisoning. The bacterium seen in longitudinal section at right is in the process of spore formation; the spore is the pale, circular region at top. Spores enable C. botulinum to survive in unfavourable conditions. The bacterium is found in soil, untreated water and badly preserved canned foods, notably meat & fish. It produces a potent exotoxin which attacks the central nervous system; death can result from heart and lung failure due to malfunctions in the cardiac and respiratory centres of the brain. Magnification: x68,000 at 8x10 inch size.