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. ------------------------------------------------------------------------ CHAPTER XLI. SOME REMARKS ON THE HYGIENE OF EATING—HOW TO OBTAIN AN APPETITE—ON MASTICATION. IF we desire to derive benefit from what we eat in order to keep the body in good condition, and thus successfully resist the onslaught of old age, we must possess a good digestion and be able to make use of our gastric juice. Without this secretion all, or the greater part, of what we eat will remain undigested in the stomach and intestines, and by its stagnation produce much disturbance and lessen the vitality of these important organs. Everything, therefore, depends upon being provided with an adequate supply of gastric juice. There are two ways of aiding this: First, by the direct action of the food on the walls of the stomach. Second, by various means which act on the nervous system that governs the glands of the stomach and provokes their secretion. As by the first means only a small amount of gastric juice is secreted, we will deal with the second.