Blood and iron

The chemical composition of blood was completely unknown until an experimenter fed iron to dogs to see if the iron would be incorporated in the blood. As a control, he checked the composition of regular dog blood and found that it already contained iron, specifically in red blood cells.
 Vincenzo Menghini Italy 1745 Blood and iron

The chemical composition of blood was completely unknown until an experimenter fed iron to dogs to see if the iron would be incorporated in the blood. As a control, he checked the composition of regular dog blood and found that it already contained iron, specifically in red blood cells.