Until the 1840s, the practice of medicine had remained relatively unchanged since the days of Ancient Greece. Germ theory revolutionized the medical world however and in the next 60 years it was transformed into a modern science. This fascinating drama series follows the discoveries that changed the world forever. The story shifts from country to country as it travels the world in search of the scientific advances that saved countless lives. From Edward Jenner's rural English practice to Louis Pasteur's laboratories in the breweries and silk farms of France and on to Robert Koch's surgery in Prussia, this BBC series brings to life the work and pressures of some of the best known scientists in history. Episodes cover lgnaz Semmelweis and the search for the cause of puerperal fever, Louis Pasteur and Robert Koch separately establishing the link between bacteria and disease and becoming bitter rivals; Pasteur's discovery of vaccines; the hunt for the Cholera germ; the first successful use of a vaccine against rabies; and Paul Ehrlich and salvarsan, the first 'miracle' drug.