Ignaz Semmelweis was a Hungarian physician whose work demonstrated that hand-washing could drastically reduce the number of women dying after childbirth. Until the late 1800s surgeons did not scrub up before surgery or even wash their hands between patients, causing infections to be transferred from one patient to another. Through vigorous statistical analysis, Semmelweis figured out where the problem lay and introduced rigorous hand-washing rules in the maternity ward. Deaths were drastically reduced and Semmelweis became known as the ‘saviour of the mothers’.
REF : http://www.sciencemuseum.org.uk/broughttolife/people/ignazsemmelweis.aspx