Virchow, then twenty-four years old and barely out of medical school, was called to consult on a medical case involving a fifty-year-old woman with implacable fatigue, a swollen abdomen, and a palpable, enlarged spleen. He drew a drop of blood from her and examined it microscopically. The sample exhibited an extraordinarily elevated level of white cells. Virchow called it leukocythemia and then simply leukemia—an abundance of white blood cells in blood.
