Antiseptic measures are the procedures for preventing the growth of micro-organisms on the skin and in wounds. Aseptic conditions, in contrast, are designed to preserve a wound from contamination by germs. The importance of antisepsis was recognized in 1847 by Ignaz Semmelweiss (1818-1865), when he identified the cause of the deadly fever that affected parturients in a Vienna hospital ward. Semmelweiss determined that the ward was attended by students who had earlier taken part in autopsy exercises. By ordering these students to wash their hands with lime chloride before visiting their female patients, Semmelweiss reduced puerperal-fever mortality in the ward from 25% to 2%.