History of medicine
There was little advance in controlling infections.  Most people believed that infections were caused by foul odors called miasmas.  Many women died of postpartum infections in hospitals because doctors did not wash their hands.  In 1847 in Vienna, Ignaz Semmelweis dramatically reduced the death rate of new mothers by making doctors clean their hands, but his work was rejected for many years.    Louis Pasteur and   Robert Koch developed germ theory in the 1860s and applied it to the epidemics of cholera. Pasteur went on to develop vaccinations.