The findings revolutionized the field of human anatomy and physiology. Today, we have techniques to diagnose and repair parts of the circulatory system. And we now have, or are close to having, replacement parts. Today, several groups are working to develop a battery-powered, implantable artificial heart. New blood vessels to help oxygenate the heart in patients with obstructed arteries are now being grown, in the body or in the lab.
Many experts cite sanitation as the single greatest advance in improving public health.
Epidemics of dysentery, typhoid, and cholera caused by polluted drinking water were common in 19th-century Europe. But in 1854, John Snow made a classic discovery, linking a single contaminated well with a cholera outbreak in a London neighborhood. His finding led to sanitation measures that dramatically reduced waterborne diseases, and the early 1900s saw the beginning of the use of chlorine compounds to disinfect municipal drinking water. Yet today, lack of clean water is still a major problem in the developing world. The United Nations estimates that one-fifth of all people have no regular access to safe drinking water.