Using a tiny, spherical glass lens sandwiched between two brass plates, the 17th century Dutch microscopist Antonie van Leeuwenhoek was the first to officially describe red blood cells and sperm cells ...

Katsuhiko Hayashi pulls a clear plastic dish from an incubator and slides it under a microscope. "You really want to see the actual cells, right?" Hayashi asks as he motions toward the microscope.