Egyptians
The River Nile The Egyptians developed a theory of illness in the body based on there observations of the river Nile. They They believed that the body was made up of channels running from the heart to the other organs and limbs. If a tree was blocking the river it would stop the flow of water, they compared this theory to the body and thought that if something was stopping the flow of blood It would cause the body to be ill and needed to be unblocked.