The scientific endeavor is influenced by scholarly trends, in that researchers have a tendency to use the hot, new scientific ideas to try and exaplain their own research. The work presented here focuses on this tendency and attemtps to measure the sensitivity of the indexing of Index-Catalogue of the Library of the Surgeon-Generalís Office of the United States Army (Index Cat) to new knowledge. The title indexing of the first three series of the Index Cat clearly reflects a shift in thinking surrounding the use of the germ theory in explaining the causes of various diseases. Title words that convey the idea of germs and the role germs play in disease occur at a much higher level towards the end of the 19th century, i.e., post-discovery of the germ theory. Not only is this affect apparent in the indexing of diseases that scholars today agree are germ based, but also in the indexing of diseases that are not now considered to be germ based. The data suggest that scientists are quick to apply the new knowledge inherent in the latest scientific breakthroughs to their own area of research.