Industrial AgeMedicine & Health Stethoscope 1816Notable René Laennec invents a tool to listen to the heart and lungs. ▲ MattersSaveShareTrace roots Longest chain: The Big Bang → First stars ignite → Supernovae seed heavy elements → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → Asteroid ends the dinosaurs → Early primates → Apes split from monkeys → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Control of fire → First fired clay figures → First pottery → Potter's wheel → The wheel → Spoke-wheeled chariot → Hittite Empire → Iron Age begins → Rome founded (traditional date) → Roman Republic founded → Caesar crosses the Rubicon → Roman Empire begins → Jesus of Nazareth crucified → Paul spreads Christianity → Edict of Milan → Christianity becomes Rome's state religion → Carolingian minuscule → Gutenberg's printing press → Vesalius' On the Fabric of the Human Body → Circulation of the blood → Stethoscope Community notesLoading notes… Learn more ranked by votesBookRoy PorterThe Greatest Benefit to Mankind ↗Editor's pickVideoSearch on YouTubeLaennec invention of the stethoscope ↗Editor's pick