Whirligigs, buzzers and other spinning toys that date to 3300 B.C. Today, diagnostics rely heavily on centrifuges, machines with rapidly rotating containers that separate fluids of different densities through centrifugal force. Centrifuges can help isolate and detect low levels of infection, pathogens and parasites in blood, urine and stool samples. They also rely on electricity and can't be used in the field. "Even places that have them, either they break in the field or, because of no electricity, are not even used.

Source: CNN January 16, 2017 09:01 UTC