It is a well-known fact that house animals, as poultry, for instance, very readily become diseased when they are not sufficiently or properly fed. In animals living in the open the same thing is often observed. The hazel hen, or heath pout, for instance, is greatly endangered by certain small organisms, the Trichostrongylus gracilis. It was noticed that, in the years during which they found plenty of food, they were much more free from these pests, and their number in the hunting season was much greater than at times when their food was scarce.
The same thing will be noticed in man. In times of famine epidemics followed as a rule, as we have seen in history. This is also true of the individual. The poor, who are not able to nourish themselves sufficiently, are much more apt to become the prey of a scourage, like tuberculosis, for instance, than the well-fed people of the upper classes. What a difference between the pale and thin tailor’s apprentice and the robust butcher-boy, and how the pale cheeks of the poor little sewing-girl contrast with the rosy ones of the girl in the meat and sausage shops!
How much better it would be for the working population I mean that of the large citiesto live in the country and till the ground ! The food of the former is often much poorer and insufficient for the work they have to do. Their nutrition is inadequate. Meat is so dear at present that they can seldom buy any, and milk and cheese are also expensive and are but poorly represented in their diet. They are consequently restricted to the cereals as a general thing. In the latter, nourishing constituents are inclosed in thick husks, which are digested with difficulty, so that, as in rye bread, as much as 40 per cent. of the so important albumin is sometimes lost. It is evident, therefore, that such mode of feeding is often insufficient, and predisposes to malnutrition.
By malnutrition we mean the inadequate intake of nutrient values in the body. Such a faulty manner of feeding is especially injurious when an insufficient quantity of albumin is absorbed. Albumin is particularly necessary during the period of growth, since the building-stones for the elaboration of the bodily structure are mainly formed by an albuminous diet. For the adult as well a sufficient intake of albumin is necessary, especially when, owing to debilitating diseases, body sub-stances have been lost which can only be replaced by an albuminous diet. Also in the normal person many cells are lost during the accomplishment of the various bodily functions, i.e., the digestion, frequent coition, the daily shedding of the epithelium, etc. ; and since all these cells must be renewed, the albumin diet must make up for the losses. When the laborer over and over again strikes his hammer upon the anvil, and continues to do this for a long time, he acquires a great muscular growth; the working muscles are better nourished owing to the continuous flow of blood into them, they increase in volume, and this muscular development can then only be successfully supported by the albumin. The labor itself is at the expense of the glycogen, and is thus carried on by the carbohydrates; the glycogen may, however, have its origin in the albumin, i.e., in the carbohydrate molecules merged with it.
According to Pettenkoffer and Voit, more oxygen is consumed during hard labor and more carbonic acid is given off. The metabolic process is activated ; and as a working machine requires more fuel than one which is standing still, so the laborer must also take more food.
In cold weather, also, more food is required. Voit and the Duke Karl Ludwig of Bavaria state that in the cold season more oxygen is absorbed and more carbonic acid given off. When the poor wear only thin clothing they give off much heat and are obliged to make up that much more. They thus require to be better nourished and must absorb more fat, since more fat is consumed. It is related of the North Pole explorers that when they had eaten heartily they felt very comfortable in their sleeping bags, but when they had not much to eat they were shivering and freezing, no matter how well wrapped up they were.
When, therefore, a poor working man has but little to eat, and is besides thinly clad, he will almost always feel hungry while at work, and will readily fall a prey to infectious diseases. How much more is this the case among the children of the poor, who are in the growing stage, and have to do mental work at school, or, having reached the age of 14, and even before then in some States, are obliged to work in factories ! How necessary it is to provide these poor school children with warm clothes in winter, and, above all, to give them meat, milk, and eggs, for it is principally among them that the disease of the poor (tuberculosis) finds the most victims! In order that the albumin intake be sufficient, at least 50 grams daily should be taken.
When children are given but a small amount of albumin a long time, the deficient nutrition involved may give rise to very serious results. Munk, Rosenheim, and Jaegerroos found that in dogs the food of which contained but little albumin the processes of digestion and assimilation were very poorly carried out. They lost fat to the extent of 28 per cent., and of the nitrogen twice or three times the normal amount. Jaegerroos’s dogs very easily fell prey to infectious diseases and finally died. Intestinal putrefaction is also increased by underfeeding (Jaffé).
The injurious effect of underfeeding upon the formation and the composition of the blood is of the greatest importance. We have already mentioned that deficient nourishment has an injurious action in this connection; also that this is especially the case during great bodily exertion. We may also mention that Munk found a general increase of the water in the tissues with insufficient nourishment. According to Grawitz, this is due to the diminution of the albumin content of the plasma. I also deem it important to quote word for word the statement of the hematologist, Grawitz. He says : “I believe that I am justified in concluding, in accordance with the views of older authors, that insufficient and poorly combined foods lead to anemia, and this most particularly when heavy bodily labor is being carried on. This is first characterized by a diminution of the albumin content of the serum, but in the later stages there is undoubtedly an alteration of the red blood-corpuscles, since the full complete integrity of the cells would ultimately become impossible, in view of the hydremic condition of the serum.”
According to Hoesslin’s experiments on dogs, chronic undernutrition, when continued for months, caused a diminution of the quantity of blood in general. According to Munk, the quantity of blood in man is also diminished, and the muscles and organs are poorly supplied or underfed, thus developing bloodless muscles and lean individuals. Panner states that starvation caused a diminution of the blood content of the body. All this may bring about most serious results, since our immunity against infectious diseases depends, as has been shown by Metchnikoff and others, upon the formation and composition of the blood, the elements of which protect us against the various bacteria. It is therefore easy to understand why chronically underfed persons easily become the prey of contagious diseases.
I would like to cite here, as an instructive example, the fact that races which feed principally upon vegetables and are poorly nourished have a comparatively short life. The Cameroon negroes, says Hans Meyer, live on an average about 40 years. Their food is mainly vegetable and consists of the starchy roots of various Euphorbiace e and Marantas, and of millet. (The assimilation of the latter, as has already been stated, is imperfect.) In contrast with these vegetarian Cameroon negroes is another African tribe, the Masai, of whom we have already spoken. They live upon a generous diet. The warriors feed only upon meat, blood, and milk; the rest of the people eat many vegetables, but also take a sufficient quantity of milk and meat. Captain Merker, in his comprehensive monograph concerning this tribe,’ states the instructive facts that the Masais live to a comparatively old age, that sickness rarely occurs among them, and is rapidly cured. It is obvious, therefore, that a plentiful, that is to say, a sufficiently ample, diet is a great protection for us. When we consider that we are constantly, by day and by night, subjected to the inroads of millions of bacteria, it is very foolish to facilitate their entrance into our tissues by insufficient nourishment. Especial care should be taken, therefore, that every one, according to his size and constitution, have the proper amount of food, and especially a sufficient quantity of albumin. Of all the various forms of bacteria to which our organism is vulnerable, the greatest danger of infection lies in the bacillus of tuberculosis, and against this a sufficiently generous diet, as we shall show in the next chapter, will best protect us.