The discovery of a cure for primary anemia, which was announced in 1926, as described in another article, has been productive of a great reawakening of our knowledge of other forms of anemia.
In order to understand this, perhaps it is best to explain what is meant by “primary” anemia, and to do that we may put the cart before the horse and tell what “secondary” anemia is. Secondary anemia is considered that form of anemia which is secondary to a loss of blood by hemorrhage. If a person has an accident which opens up a large blood vessel, and loses one or two quarts of blood, the total amount of blood in the body will naturally be diminished and will have to be replaced by the blood-forming organs. The principal blood-forming organ is the marrow of the bones.
In contrast to this secondary form of anemia, primary anemia is that form in which the total amount of blood is diminished, the total amount of cells in the blood is diminished, and yet there has been no direct loss of blood from hemorrhage of any kind. We assume in these primary anemias that the diminution of the blood cells is due to some poison working on the bone marrow which, as we have just said, is the source of blood production.
When it was found about 10 years ago that primary anemia of the pernicious type could be cured by having the patient eat liver, it was difficult at first to understand how this treatment operated. Then it was emphasized that in cases of primary anemia the stomach was always at fault in that no stomach juice was secreted. The stomach wall in people with this disease was known to be so thin as to be almost transparent.
With this idea in mind, Dr. Castle, in Boston, fed normal people meat, recovered it with a stomach tube, and feeding this meat, which had been impregnated with normal stomach juices, to patients with anemia, he found it worked as well as liver. The assumption at present, therefore, is that there is a substance elaborated in the wall of the stomach, incorporated in the process of digestion into the food, which is carried to the liver and stored there and which, doled out to the blood, stimulates the bone marrow to production of red blood cells,
Having these data at hand doctors began to notice that there were certain types of primary anemia which did not respond to liver. These patients have, as is true in pernicious anemia, an atrophy of the stomach wall and lack of stomach contents and reduction of their total blood volume. But they differ from the pernicious form in not clearing up with liver feedings. Casting about for a manner of treating them it was found that the old original method of treating anemia with iron, and which had long been unfashionable, worked in them perfectly. So that we now have two classes of primary anemiaone that responds to liver feeding, and one that responds to iron feeding.