Properties : Ferrous carbonate is made by precipitating a solution of a soluble ferrous salt by a soluble carbonate. Such a precipitate tends to give off carbon dioxid. absorb oxygen and change rapidly into a basic carbonate, and finally into ferric hydroxid. Various pharmaceutical processes have been devised to prevent such a change. The principal of these are the preparations described below as Vallet's mass (massa ferri carbonatis) and Blaud's pills (pilulae ferri carbonatis).

Action and Uses: The action of all forms of iron is essentially the same so far as the action of the iron ion is concerned. When an iron salt is received into the stomach it may be converted into a chlorid, but this is further changed during the process of digestion. The original form in which the iron was combined seems to make little or no difference in regard to the extent or the form in which it is absorbed. A large part of the iron ingested passes through the intestines without being absorbed. A smaller portion is absorbed, mainly through the lymph, and is deposited for a time in the blood-making organs, chiefly the spleen, where it is retained for an indefinite time as "reserve iron." Some of this supply is used in forming hemoglobin, which enters into the red blood-corpuscles. The rest is eliminated by the mucous membrane of the large intestine and only traces by the kidneys. Iron is not eliminated by the bile. The presence of iron in the blood in the amount resulting from medicinal administration produces no recognizable changes in normal individuals. Its salts with the stronger acids may act as gastro-intestinal irritants and astringents.

The only therapeutic action attributable to the iron ion is the improvement in the number of red blood-cells and in the amount of hemoglobin in them. For this purpose it is indicated in anemia and in diseases of the blood in which anemia is a factor, such as leukemia. It is chiefly of value in anemia following hemorrhage, in chlorosis and in secondary anemias. In pernicious anemia it seems to be useless, but may be given along with arsenic.