The 19th century was also a time for innovation and development. Throughout history those were considered health care leaders have influenced the well-being of a society. A leader is often the person who creates or deal with change upon the needs of a society. Dr. John snow, a physician is an example of how a leader can change the entire community by identifying and acting upon a need for change. In the 19th century, john snow was able to contain a major outbreak of cholera in London. Although he was not a nurse, I mention Dr. Snow here because his role in controlling a major outbreak of cholera with little sophisticated equipment or knowledge of bacteriology was critical. Snow and his assistants calculated the actual number of deaths from