In 1843, Holmes published The Contagiousness of Puerperal Fever which argued that puerperal fever, a deadly disease of women giving birth, was frequently carried from patient to patient by physicians and nurses.^[8] A few years later, Ignaz Semmelweis would reach similar conclusions in Vienna, where his introduction of prophylaxis (handwashing in chlorine solution before assisting at delivery) would lower the puerperal mortality rate considerably. Holmes, seeing more clearly than Semmelweis that something like microbial action must be involved -- his famous essay was an uncanny anticipation of Pasteur's discovery of the germ theory of disease later in the century -- was altogether more radical. A physician in whose practice even one case of puerperal fever had occurred, wrote Holmes, had a moral obligation to purify his instruments, burn the clothing he had worn while assisting in the fatal delivery, and cease obstetric practice for a period of at least six months. http://en.wikipedia.org/wiki/Oliver_Wendell_Holmes,_Sr.