With the introduction of antiseptic methods, surgery entered its modern phase. Louis Pasteur established the fact that microbes are responsible for infection and disease. Using this knowledge, Dr. Ignaz Semmelweis reduced postpartum infections (puerperal sepsis) in the wards of Vienna's lying-in hospitals by urging doctors to wash their hands between patients. In the 1860s Joseph Lister introduced the use of carbolic acid as a cleansing and disinfecting agent, and his results in reducing infection were dramatic. It was found later that the carbolic acid spray that Lister used to cleanse the air about the patient was unnecessary, but the antiseptic treatment of instruments and other articles in contact with the patient continued until antisepsis was gradually replaced by the aseptic methods employed in modern hospitals. Before the discovery of antisepsis by Lister, about 80% of surgical patients contracted gangrene.
Ernst von Bergmann is credited with introducing steam sterilization under pressure for treating instruments and all other medical equipment used for a surgical patient. William Stewart Halsted, the famous surgeon at Johns Hopkins Hospital, introduced sterile rubber gloves when the hands of his fiancée became irritated from constant washings and antiseptics. The development of methods of anesthesia, especially the discovery in the 1840s of the value of ether, has also been of immeasurable value.