Louis Pasteur (1822-1893) held many academic posts and received numerous awards both in France and abroad. His investigations into fermentation, food preservation, diseases affecting silkworms, anthrax and fowl cholera had tremendous commercial applications and led to conclusions that revolutionized physiology, pathology, and therapeutics. His discovery that most familiar diseases are caused by germs is one of the most important in the history of medicine and brought vast changes in hospital practice. By his studies in the culture of weakened strains of bacteria, Pasteur greatly extended the practice of inoculation with a milder form of various diseases, in order to produce immunity.

Joseph Lister (1827-1912) was surgeon to the Royal Infirmary in Glasgow, Scotland, where for eight years he developed his system of antiseptic surgery. He investigated a number of problems relating to postoperative inflammation and pus formation and the coagulation of blood in wound healing. Aware of Pasteur's work on the relation between microorganisms and putrefaction, Lister came to realize that postoperative infections were due to bacteria. His antiseptic methods of surgery gradually won wide acceptance, thus greatly reducing levels of infection and death following surgery. Later in his career, Lister became surgeon to Queen Victoria.