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.
Darwin officially published his theories in On the Origin of the Species in 1859. He knew his views would be controversial, especially with those who believed heavily in religion. His first edition of the book did not talk much about human evolution, but did hypothesize that there was a common ancestor for all life.