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.
Sociologists in the 19th century applied Charles Darwin's (1809â1882) work in biological evolution to theories of social change. According to evolutionary theory, society moves in specific directions. Therefore, early social evolutionists saw society as progressing to higher and higher levels.