[The Semmelweis reasoning and the puerperal fever].

Ignaz Philipp Semmelweis is probably one of the most important personalities of the history of medicine in nineteenth century before the microbiological Pasteur's revolution. Young doctor, troubled by the numerous deaths occurring at the obstetrician department in Wien, were he had been temporarily employed, despite the unavailability of laboratory instruments, he could get, by means of empirical observation and deductive reasoning, what all the other contemporary scientists had not been able to perceive: the responsibility of puerperae's mortality was to ascribe to genital contamination that occurred through the hands of doctors visiting them after having performed autopsies. Semmelweis is a romantic figure, who also paid for his political and cultural engagement in Wien in 1848 with social isolation. His uneasy temperament, and some difficulties in the relationship with his colleagues, didn't promote his ideas to be accepted and spread. Few years following his death, prematurely occurred in unclear circumstances, thanks to Pasteur's discoveries, his battle was eventually recognized.