Iron is a most important element of our blood, the lack of which, as in chlorosis and various anæmic conditions, may produce very serious symptoms. To replace this deficiency iron is introduced into our system, and this can be done in two ways: either by the natural way, i.e., by food which contains iron, or artificially, by means of drugs which contain iron. It is the opinion of Bunge that iron, given in drugs, especially as inorganic iron, is not so readily absorbed and assimilated as organic iron, i.e., iron as it occurs in various articles of food, and especially in the blood.

Therefore an effort has been made with more or less success by manufacturing chemists to make preparations of iron obtained from the blood, and Professor Bunge^[299] has experimented on animals by using iron containing nuclein, separated from the yolk of eggs; and in Professor Kossel’s laboratory such a preparation has been made from the eggs of the carp. It was found that these preparations were perfectly absorbed and assimilated.

Professor Bunge, and also his pupils Abderhalden and Haüsermann, found that all animals which received food containing but little iron, became anæmic, e.g., young rabbits fed only on milk, which, as above mentioned, is very poor in iron. Later food was given that contained iron (as green vegetables, cabbage, herbs, etc.; or meat, yolks of eggs, and fruit), and soon afterward the iron contents of their blood was found to be increased. Even if we are not anæmic or chlorotic, it is necessary to take a certain amount of iron, preferably organic iron, into our systems.

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.

Bunge mentions that the chlorotic girls of Basel (Bâle) come to the slaughterhouses in order to drink the blood of animals that have just been slaughtered. The question arises as to which animal’s blood is the best. That of the pig is preferable for several reasons. Its blood contains much iron (according to Bunge 226 milligrammes in every 100 grammes), its organs are anatomically and histologically very like our own, and the pig is an omnivorous animal, as we are, being able to eat even 14 to 20 pounds of meat a day. Several of the organo-therapeutic preparations, like ovarian extracts, and testicular and kidney extracts, are, if obtained from the pig, more active than those obtained from other animals. And, finally, from pigs’ blood very savory sausages and puddings can be prepared.

In Denmark and Norway a favorite pudding is prepared from pigs’ blood, together with flour, sugar, barley, groats, and raisins, and we have found it very palatable. In these countries many physicians prescribe this pudding and blood sausages (in England called “black puddings”) to chlorotic girls.

We consider pigs’ blood to be of very great value, not only on account of its iron, but also because it contains, as does blood in general (according to Claude Bernard), extracts of the ductless glands in their most assimilable form, and by taking this blood we, at the same time, introduce these organic extracts. To obtain the greatest possible benefit from these properties the blood should be drunk fresh; but as this is not very easy to do for obvious reasons, we can substitute blood sausages and black puddings. Blood contains chemical substances of great importance, as iron, manganese, phosphorus and small quantities of iodine, besides also lecithin, glycogen, glucose, jecorin, etc. It also contains important ferments, as diastase, and sugar- and fat-splitting ferments. Likewise it contains important immunizing substances, opsonins, alexins, etc.

The blood of pigs is very nourishing, for it is rich in albumin. Indeed, considering that this blood is wasted in the slaughter houses, it is necessarily the cheapest kind of food. And it is also an article of food which is easily digested, absorbed, and assimilated. It is hard to understand why this article of diet has not been made more use of long ago. Professor Bunge, the well-known physiologist, likewise strongly recommends the use of blood as an important article of diet. We show in the following table, compiled from the researches of Abderhalden,^[302] the composition of pigs’ blood and of ox blood in respect to their nourishing qualities and different mineral contents.

According to the researches of T. König,^[303] Farwick and C. Kraut blood sausages have the following composition:—

Experiments were made in England centuries ago by transfusing the blood of young animals into the veins of old animals (sheep, cows, and horses), which latter, by this means, became more lively and active. In some cases the special senses became more acute—hearing especially, according to Dr. Hufeland. On man such transfusion has also been tried; Dever and Riva,^[304] in Paris, succeeded in treating certain diseases by transfusion of animals’ blood, and, as Hufeland states, a lunatic recovered his health after transfusion with calves’ blood.

It is strange that this treatment is not more used now. Should we not be able to treat certain diseases, such as old age, by transfusing the blood of younger individuals, or of certain animals? This is certainly a bold question, and we are not yet in a position to answer it definitely. We must take into consideration the fact that the transfusion of blood, even though human, into other individuals presents certain dangers. Bier has tried transfusion in a few cases of lupus, and there appeared at first symptoms of intoxication followed later by a marked amelioration. But if transfusion by present surgical methods is not free from dangers we can give the blood in a more rational manner by the mouth. As Bunge has shown, the hæmatin is absorbed by the intestines, while the diapedesis of the blood corpuscles themselves through the intestines has been demonstrated in the experiments of Grawitz. The serum of Moebius (anti-thyroidin) also acts if taken by the mouth.

At the present time nothing hinders us from using the blood of pigs in the way just mentioned. But care must be taken to obtain fresh and healthy blood. Pigs often get pneumonia through catching cold during transportation. Therefore those pigs whose blood we use must have been previously specially examined.

For this purpose also pigs should not be too fat. As we learned from observations in the slaughter houses, a fat pig of 200 pounds may not have more than a liter of blood, whereas oxen of 900 pounds have nearly 10 to 12 liters of blood. Still, for reasons already mentioned, preference should be given to pigs’ blood.

It is most important that, when the diet consists of much milk and little or no meat, some iron-containing food be taken in addition.