During Pasteur ’ s life, the application of antiseptics was introduced. It had been shown in 1846 by Ignaz Semmelweis that chlorine could control infection, and in 1865, Joseph Lister showed that the same could be done with carbolic acid. Later, Paul Ehrlich used synthetic dyes and established the concept of the “ magic bullet. ” Towards the end of the nineteenth century, Ehrlich began testing many synthetic compounds. He achieved success in 1909, curing relapsing fever, syphilis, and trypanosomiasis with an arsenical product called Salvarsan or Compound 606 (because it was his 606th attempt to produce an arsenical compound which killed the syphilis bacterium in vivo without harming the host). This was the first chemotherapeutic drug ever discovered and he coined the term “ chemotherapy. ”