A Note on Semmelweis's Animal Experiments and Their Historical Significance

This article seeks to establish what animal experiments Semmelweis conducted, and when and why he conducted them, because the Semmelweis literature contains conflicting claims about these topics or has ignored them altogether. Semmelweis first conducted animal experiments between 22 March and 20 August 1849 with Rokitansky's assistant, Georg Maria Lautner, because his chief, Johann Klein, did not accept that by merely reducing the mortality rate from childbed fever with chlorine hand-disinfection, Semmelweis had proved his theory of the cause of childbed fever. However, Skoda concluded that the Lautner experiments did not resolve the doubts about Semmelweis's theory they were intended to resolve, and, therefore, asked the Academy of Sciences to award Semmelweis a grant to conduct further and more varied experiments with the physiologist, Ernst Ritter von Brucke. These additional experiments were conducted in the spring and summer of 1850, but yielded only ambiguous results, and led Brucke to conclude that questions about Semmelweis's theory could only be resolved by clinical observations, not animal experiments. This article discusses the reasoning behind these animal experiments, and Skoda's and Brucke's responses to them, and argues that their responses to the experiments caused Semmelweis to delay publishing his research until he had collected sufficient clinical evidence to prove his theory.