While indigenous nurses expertly used herbal medicines, tribal shamans cured people of staying sickness that existed only within specific tribal communities. However, neither indigenous nurses nor shamans could consistently address new illnesses caused by viruses and bacteria. As a result, and with time, the first people of Southern California agreed to incorporate Western medicine into their own medicine ways. During the early twentieth century, Southern California Indians gradually used Western medicine and integrated new medicine ways into their cultural circles. Once Western medicine proved effective in preventing and curing illnesses, Indians incorporated new medicine into their lives. They slowly brought Western medicine into their own cultural circles and adopted new ways of healing without abandoning their own medicine ways. In essence, Native Americans gradually chose to incorporate Western medicine into their cultures and use it to their advantage. At the same time, they kept their traditional medicine ways. They used both ways to achieve better health. They continued to consult traditional tribal nurses and shamans, drawing on expertise of traditional and new medicine to benefit their people. This form of integrated medicine has continued to this day through community-based and Native-controlled contemporary Indian health centers located throughout Southern California. However, in the 1920s, the Indians of Southern California were just learning about field nurses and important national changes brought to the Indian Service.