Timeline of medicine and medical technology 420 BC - Hippocrates begins the scientific study of medicine by maintaining that diseases have natural causes and puts forth the Hippocratic Oath, marking the birth of modern medicine 280 BC - Herophilus studies the nervous system and distinguishes between sensory nerves and motor nerves 250 BC - Erasistratus[?] studies the brain and distinguishes between the cerebrum[?] and cerebellum 50-70 - Pedanius Dioscorides writes De Materia Medica - a precursor of modern pharmacopeias that was in use for almost 1600 years 180 - Galen studies the connection between paralysis and severance of the spinal cord 1242 - Ibn an-Nafis[?] suggests that the right and left ventricles[?] of the heart are separate and describes the lesser circulation of blood 1249 - Roger Bacon writes about convex lens spectacles for treating long-sightedness[?] 1403 - Venice implements a quarantine against the Black Death 1451 - Nicholas of Cusa[?] invents concave lens spectacles to treat myopia early 16th century: Paracelsus, an alchemist by trade, rejects occultism and pioneers the use of chemicals and minerals in medicine 1543 - Andreas Vesalius publishes De Fabrica Corporis Humani which corrects Greek medical errors and revolutionizes medicine 1546 - Girolamo Fracastoro proposes that epidemic diseases are caused by transferable seedlike entities 1553 - Miguel Serveto[?] describes the lesser circulation of blood through the lungs 1559 - Realdo Colombo[?] describes the lesser circulation of blood through the lungs in detail 1603 - Girolamo Fabrici[?] studies leg veins and notices that they have valves which only allow blood to flow toward the heart 1628 - William Harvey explains the vein-artery system and structure of the heart in De Motu Cordis et Sanguinis 1701 - Giacomo Pylarini[?] gives the first smallpox inoculations 1747 - James Lind discovers that citrus fruits prevent scurvy 1763 - Claudius Aymand[?] performs the first successful appendectomy 1790s - Samuel Hahnemann rages against the prevalent practice of bloodletting as a universal cure and founds homeopathy 1796 - Edward Jenner develops a smallpox vaccination method 1800 - Humphry Davy announces the anaesthetic properties of nitrous oxide 1816 - Rene Laennec[?] invents the stethoscope 1842 - Crawford Long[?] performs the first surgical operation using anasthesia 1847 - Ignaz Semmelweis studies and prevents the transmission of puerperal fever[?] 1870 - Louis Pasteur and Robert Koch establish the germ theory of disease 1881 - Louis Pasteur develops an anthrax vaccine 1882 - Louis Pasteur develops a rabies vaccine 1890 - Emil von Behring discovers antitoxins[?] and uses them to develop tetanus and diptheria[?] vaccines 1906 - Frederick Hopkins[?] suggests the existence of vitamins and suggests that a lack of vitamins causes scurvy and rickets 1907 - Paul Ehrlich develops a chemotherapeutic cure for sleeping sickness 1921 - Edward Mellanby[?] discovers vitamin D and shows that its absence causes rickets 1928 - Alexander Fleming discovers penicillin 1932 - Gerhard Domagk[?] develops a chemotherapeutic cure for streptococcus 1952 - Jonas Salk develops the first polio vaccine