C. difficile diarrhea is largely a nosocomial disease and is the most frequent cause of diarrhea in hospitalized patients. Its occurrence in the outpatient setting, other than in patients confined to nursing homes, is much less common.
Darwin had arrived at a complete theory of evolution by 1839, but it was to be another 20 years before he published his ideas of evolution through natural selection in his epochal book On the Origin of Species by Means of Natural Selection.
The idea that life on Earth has evolved was widely discussed in Europe in the late 1700's and the early part of the last century. In 1859 Charles Darwin supplied a mechanism, namely natural selection, that could explain how evolution occurs. Darwin's theory of natural selection helped to convince most people that life has evolved and this point has not been seriously challenged in the past one hundred and thirty years.