Anæmia of slight degree is very frequent in women, especially after degeneration of the ovaries, as after the menopause. As we have already mentioned, the ovaries influence in a remarkable way the condition of the blood. In the adult the bone marrow is the chief seat of formation for the red blood corpuscles; but the bone marrow, and indeed the whole skeleton, as we have shown in the second chapter of this book, is under the control of the ovaries and of the thyroid. As these organs are, as a rule, degenerated in old age, anæmia must result, and indeed Prof. Naunyn[300] says: “Old people are anæmic.” Geist has already emphasized the diminution in the quantity of the blood in old age. That blood formation is deficient in old age is demonstrated by Besançon and Labbé, who found the activity of the bone marrow diminished in old age, and by Grawitz,[301] who found that bone marrow underwent important changes in old age, being transformed into a jelly-like substance. According to Grawitz, iron—and he always prefers to prescribe an organic rather than an inorganic iron preparation—is less efficacious in old age. We attribute this to the degeneration of the blood-forming organs, through whose intermediary action iron produces its effect. If, however, these organs are not entirely degenerated, but only partially so, as in the first few years following the menopause—in women until the end of the fifties—we can obtain better results; and indeed after giving such women iron we may observe that they look better, and often fresher (see, also, Chapter LIII). As organic iron is more easily assimilated, this form is to be preferred, and the question arises: How should we take it? Of all kinds of food used at present, spinach and the yolk of eggs contain the most iron; so we could give these. Fortunately spinach is obtainable at all seasons in the United States. For those who prefer eggs, yolks in quantities large enough to satisfy our needs would not be easily digested, and also as eggs would be difficult to procure fresh every day, we must think of another expedient. We may take iron preparations obtained from the blood of animals. But why not take the blood itself, which contains iron in a form similar to that in our blood, and in larger quantities than in any other food? This would certainly be more efficacious, and also less expensive. Footnote 300: Naunyn: In Schwalbe’s Lehrbuch der greisenkrankheiten, Berlin, 1909. Footnote 301: Grawitz: Hidem and also in “Klinische Pathologie des Blutes,” third edition, Leipzig, 1906.