Sir Joseph Lister, Baron Lister of Lyme-Regis, was a famous English surgeon who became the world's foremost authority on preventing infection of wounds and surgical incisions in the late 19th and early 20th centuries. Through observations and experiments, Lister became convinced that cleanliness could prevent many infections in operating rooms and surgical wards. After hearing of the research of French scientist Louis Pasteur showing that rot was caused by micro-organisms, Lister pioneered the use Carbolic Acid (Phenol) to kill disease organisms in hospitals. In Lister's own words:

But since the antiseptic treatment has been brought into full operation, ... my wards, though in other respects under precisely the same circumstances as before, have completely changed their character; so that during the last nine months not a single instance of pyæmia, hospital gangrene, or erysipelas has occurred in them. As there appears to be no doubt regarding the cause of this change, the importance of the fact can hardly be exaggerated.

Although the use of Carbolic Acid has given way to safer antiseptics, Lister's principles continue to guide medical practice to this very day. The following link leads to Lister's 1867 medical journal publication reporting his findings, one of the masterpieces of applied science.