Blood is a body fluid in humans and other animals that delivers essential substances such as nutrients and oxygen to the cells, supports the body’s temperature and moves waste products away from those same cells. In 1616, William Harvey discovered that blood circulation is the key factor in physical life. The great biological truth concerning the importance of blood in our body’s mechanism has been fully comprehended only in recent years. Till 120 years ago, sick people were bled, and many died because of the practice.
Almost 3500 years ago Bible mentioned this fact and declared that blood is the source of life in the book of Leviticus chapter 17 verse 11
Leviticus 17:11: For the life of the flesh is in the blood….NKJV
Blood is far more complex and has far more to do with life than science ever imagined. About 55 percent of the blood is composed of plasma. The rest is made of three major types of cells: red blood cells, white blood cells, and platelets. Antibodies in the blood neutralize or help destroy infectious organisms. Each antibody is designed to target one specific attacking organism. There is no better way to describe the function of blood in relation to the human body than to say, “The life of the flesh is in the blood”.