Willem Einthoven's fortuitous invention.
It is usually assumed that Willem Einthoven started out as a young investigator to invent the electrocardiograph and that he succeeded. On the contrary, his career had several false starts. True, fortune smiled on him. But his diligence and clinical interest plus the scientific freedom of his age led to his remarkable discovery.
D002309:Cardiology / Q000266:history; D004562:Electrocardiography / Q000266:history* / Q000295:instrumentation; D049672:History, 19th Century; D049673:History, 20th Century; D009426:Netherlands; D009613:Nobel Prize