Although Hungarian obstetrician Ignaz Semmelweis did not know the true cause of puerperal fever, he proposed that physicians were transferring the causative agent to their patients. He suggested that the number of cases could be reduced if physicians and medical students washed their hands with chlorinated lime water before and after examining every patient. When this handwashing protocol was implemented, the maternal mortality rate in people cared for by physicians dropped to the same ${}1$% mortality rate observed among people cared for by midwives. This great success demonstrated that handwashing was a highly effective method for preventing disease transmission. Despite this, his work was initially discounted because physicians were slow to adopt the simple procedure as it contradicted established norms for that time period. Along with John Snow's research, Semmelweis's work clearly refuted the prevailing miasma theory of the day, showing that disease is not only transmitted through the air but also through contaminated items.