False-colour transmission electron micrograph of the Gram-positive anaerobic bacteria Clostridium botulinum, responsible for serious food poisoning in humans. C. botulinum grows in badly preserved canned foods, notably meat & fish, & produces the potent exotoxin that causes botulism poisoning. The toxin affects the central nervous system of humans; in fatal cases death results from heart & lung failure due to malfunctions in the cardiac & respiratory centres of the brain. Magnification: x13,960 at 6x4.5cm size.