Patients who went into hospital up until the late 19th Century only had a 50/50 chance of coming out alive.
Surgeons didn't wash their hands between patients and believed illnesses were passed on through the air.
Joseph Lister knew carbolic acid was used to disinfect sewage. In 1867, he published a paper in the British Medical Journal in which he explained how he had used carbolic acid to treat patients with serious bone fractures.
The acid, he wrote, "appears to exercise a peculiarly destructive influence upon low forms of life".
Lister described washing wounds with the acid to destroy "septic germs". He then wrapped the wound in an antiseptic paste, made of carbonate of lime, carbolic acid and linseed oil, and the bone healed without infection.
But his research was not immediately accepted in his home country. Colleagues did not believe that bacteria existed because they could not see them, and his theory was first accepted in Europe and the US.