Food exerts so great an influence upon man that even the size of his body may be essentially affected thereby. Thus, we see that nations which nourish themselves with articles of diet rich in nitrogenous elements, that is, with plenty of meat, in addition to a sufficient quantity of the other main groups of foodstuffs, e.g., the English, the Swedes, and other nations living in a similar way, attain to a considerable physical development.
One might, perhaps, attribute this circumstance to the influence of the cold and damp climatic conditions, but even in Africa there is a tribe, the Watussi, which is richly nourished, since its members possess extensive herds of animals, with plenty of pasture land, and these people, according to the description given of them by Duke Adolf Frederick of Mecklenburg, are also noted for their great physical development. Among them there may be seen. many individuals of a height of 2 meters, and even more. When, however, an exclusive nitrogenous meat diet is indulged in, as with the Eskimos, growth is hindered, and low stature is the rule. Not in this case either can the climate be considered a factor, for in that of tropical Africa there may be found, in addition to the above-mentioned giants, tribes of dwarfs, the Batwa and the Warnbuti. These forest-living dwarfs are like the Eskimos in that they also feed almost exclusively upon meat. There can be no question of coincidence in the matter. There must there-fore be a certain relationship between modes of nutrition and growth. This relationship must be of such a nature that, in the pronounced growth of those persons living upon a diet rich in meat, a certain influence is brought to bear upon the organs which regulate bodily growth. These organs are the thyroid gland, the sexual glands, and the hypophysis. They influence, in particular, the metabolism of lime and phosphorus, which are the main elements of which the bony structure is composed. When these organs have degenerated, growth does not usually take place, and when there is defective development of the sexual glands the well-known dwarf-like condition of the cretins often occurs. The experiments of Briesacher, Blum, and others have proven that a meat dietand this preferably not in the form of meat which has been boiled outhas a stimulating influence upon the thyroid gland. The in-creased growth of the nations named above can be accounted for in this way,also the fact often observed among our own people, viz., that the children of the wealthy who often eat roast meats and other articles of food rich in nitrogenous substances frequently grow very tall, while, on the other hand, the children of poor people often develop very slowly. This would likewise afford an explanation of the large number of tall persons in the aristocracy, and among the well-to-do classes where riches have existed during generations, as in the patrician families.
In animals, as, for instance, in the horse, the same facts may be observed : the English race horses, well fed with oats, present a marked contrast to the puny Hungarian farm horses, fed principally with hay.
The children of stunted growth seen in the poorer classes can often be made to grow more rapidly by generous feeding and perhaps even artificially, so to speak, by the administration of extracts of the thyroid and sexual glands of animals. Hertoghe has shown that a surprising development occurs in backward children after treatment with thyroid extracts. This is plainly to be seen in the illustrations he published. I have frequently obtained the same results by the administration of thyroid extract. Thus, last summer, after six weeks’ combined treatment with thyroid and testicular extract in the case of a 14-year-old lad, with undeveloped sexual glands, a very marked increase in growth was observed, about i cm. each week. There occurs also a remarkable development of the mentality in such children. Practically the same results may be brought about by a carefully selected diet during the period of development in children. I may here also cite a surprising example of this in the plant world. If a plant is given plenty of nitrogen in manure, it will grow to twice the height, or even more, that a similar plant without manure will, especially if phosphorus is added to the fertilizing agent.
When nourishment is poor and insufficient, man cannot develop properly; thus, Burton found the inhabitants of Dahomey very small and shriveled in appearance. Their food is miserable; in order to get meat, they are obliged to fatten dogs and eat them.
When, on the other hand, the food consists almost exclusively of meat, as with the Eskimos and the dwarf tribes of the virgin forests, here, again, man cannot grow properly. There must here be some injurious action, due to the excessive meat diet, upon the ductless glands which regulate the growth of the body, viz., the thyroid and sexual glands. That this actually does occur has been shown by the experiments of Chalmers Watson and of Hunter. Chalmers Watson found that the thyroid gland of rats and of chickens fed only upon meat became degenerated. More recently Chalmers Watson and Hunter have shown the following: Of 14 rats fed on meat alone, only 8 remained alive. During the eight months of the experiment, it became evident that the development of these animals was entirely arrested, and that they did not grow at all. Houssaye kept hens upon a meat diet, and they laid no eggs. It can, moreover, be observed that hens stop laying and grow coarse, wild feathers when farmers are care-less enough to give them meat or blood as food. This clearly demonstrates the influence of food upon the outward appearance of animals. An instructive example of this fact, related by Roberts, may here be cited : In the Amazon region there is a variety of green parrot. When the natives feed these birds with the fat of large fishes of the siluroid class, found in the Amazon, which food the birds greatly enjoy, these parrots grow a coat of beautiful red and yellow feathers. In the Malay Archipelago a kind of parrot is found which is called Lori Rajah”King Lori.” With the usual rice food these birds are unattractive in color, but if they are fed upon fish their feathers take on a brilliant hue.
In order that man shall thrive on his food, it must be varied, and, above all, it must contain sufficient nitrogen, i.e., albuminthough not too much, or it may prove injurious. When, however, the diet contains too little thereof, it is much more harmful. We see this in the Hindoos, who live mainly upon rice and millet. They, as well as the majority of Japanese people, who also feed almost exclusively upon rice, and likewise the Chinese and the Malays, are all thin; and since the nitrogen is not sufficiently represented in their nourish-ment, they very rarely grow tall, with the possible exception of the Manchus, who resort to a rather richer nitrogenous diet. Chalmers Watson and Andrew Hunter also showed, in their experiments already referred to, that young rats fed only upon rice were backward in growth.
The vegetarian negro tribes also remain lean. Stout people are almost never seen among them, while, on the contrary, the negroes living upon a mixed diet in the United States often show a considerable abdominal development. In my country, too, there is no lack of persons with overdeveloped abdomens, and the majority of those people who, together with a sufficient meat diet, eat plenty of pastry and sweets, and like-wise drink much beer, may of a certainty count upon such an alteration in their appearance. In this connection the duct-less glands, those wonderful structures the influence of which upon the entire organism I have more fully described in my work “Old Age Deferred,” play an important rôle, inasmuch as they regulate the metabolic processes of the organism.
Upon the outer covering of the bodythe skinthe food also has an influence. This, in many persons, shows itself in the occurrence of rashes and eruptions after the ingestion of certain foods, as cheese, strawberries, etc. When the flesh of animals which subsist in an unclean medium, as do occasionally the oysters, or which eat refuse and decomposing substances, as do lobsters and crabs, is eaten, such an eruption is frequently observed to appear. Comparable with this is the occurrence of eczema after fish that is not fresh has been partaken of. Very interesting is the appearance of widespread eruptions such as those which occur in Java when one has eaten a kind of mango fruit, the mangoguani. In Brazil it is a well-known fact that persons, and especially those who have once had syphilis, may count with certainty upon having a widely diffused eruption of the skin after having eaten of the meat of the tapir. This animal feeds upon all manner of refuse, and very often there may be found in its stomach pieces of wood, lumps of earth, etc. It is very probable that the above symptoms, appearing after one has eaten fruit grown in an unclean soil or the meat of animals which ingest injurious substances as food, are to be regarded as the result of the poison-eliminating function of the skin.