Various theories as to the cause of this disease had been proposed, yet no one had solved the mystery. All attempts to reduce the mortality rate proved futile. Troubled by the spectacle of numerous mothers suffering a slow, agonizing death, Semmelweis determined to find the cause of the disease and prevent it.

The hospital in which Semmelweis worked had two separate maternity clinics, and curiously, the maternal death rate was much higher in the first clinic than it was in the second. The only difference between the two clinics was that medical students were taught in the first and midwives in the second. Why, then, such a difference in death rates? Probing that question, Semmelweis systematically eliminated possible causes of the disease, but the culprit remained elusive.

In early 1847, Semmelweis was presented with a crucial clue. His colleague and friend Jakob Kolletschka had died from blood poisoning after sustaining a wound while performing a postmortem examination. As he read the report of the autopsy performed on Kolletschka, Semmelweis realized that in some aspects, the findings were identical to those of the victims of childbed fever. Hence, Semmelweis thought that perhaps what he termed “poisons”  from cadavers were infecting pregnant patients, thus causing childbed fever. Doctors and medical students, who frequently did autopsies before going to the maternity ward, had unwittingly been transmitting the disease to expectant mothers during obstetric examinations or childbirth! Mortality in the second ward was lower because students of midwifery did not perform autopsies.

Semmelweis immediately introduced a strict policy of handwashing, which included sterilizing the hands in a solution of chlorinated lime before initiating examinations of pregnant women. The results were dramatic: mortality rates plummeted from 18.27 percent in April to 0.19 percent by the end of the year.

Not all welcomed Semmelweis’ success. The results he obtained challenged the theories concerning childbed fever held by his superior, who also found Semmelweis’ insistent manner irritating. Semmelweis eventually lost his post in Vienna and returned to Hungary. There he took charge of the obstetrics department at the St. Rochus Hospital in Pest, where his methods brought down the mortality rate for childbed fever to under 1 percent.

In 1861, Semmelweis published his life’s work, The Cause, Concept, and Prophylaxis of Childbed Fever. Unfortunately, the importance of his findings was not recognized until some years later. In the meantime, countless lives that could have been saved were tragically lost.

Semmelweis was eventually recognized as one of the fathers of the modern antiseptic technique. His work helped to establish that microscopic matter can cause disease. He is part of the history of the germ theory of disease, which has been called “the single most important contribution to medical science and practice.” Interestingly, over 3,000 years earlier, the Mosaic Law, which was later included in the Bible, had already provided sound guidance on the proper handling of corpses.