In 1847 Hungarian physician Ignaz Semmelweis brought down infant mortality at a Vienna hospital by disinfection. Unfortunately, disinfection did not become widely practiced until British surgeon Joseph Lister 'discovered' antiseptics in 1865 after Louis Pasteur's work. In the early 20th century, mathematical methods were introduced into epidemiology by Ronald Ross and others. In 1954 came the results of a study led by Richard Doll. This gave very strong statistical support to the suspicion that tobacco smoking was linked to lung cancer.