Scanning electron micrograph (SEM) of household dust collected from a vacuum cleaner. The sample shows a preponderance of sand and grit particles coming from the builder's yard next to the house. Also visible are skin scales, nylon & synthetic fibres, cat fur & flea droppings. The single smooth oval in the centre of the micrograph is an egg of the cat flea (Ctenocephalides felis). Magn- ification: X 14 at 35mm size, X 96 at 8x10-inch size.