This metal is a normal constituent of the body, existing in appreciable, though minute, quantities in the blood, bile, etc. From the fact of its presence in the blood, and because of the similarity of its chemical affinities to those of iron, many observers have advocated its use as a worthy and efficient substitute for the latter agent.

Its therapeutic uses as a restorative, or as an alternative or synergist to iron, are based more upon abstract deductions than upon clinical observation. Still, as its chemical character resembles that of iron - though the metal in its operation is often antagonistic to the latter - its salts are of sufficient therapeutic importance to merit brief mention here.