2. We know that the development of energy that the organism puts forward is a function of the albuminous protoplasm of its cells. If we were able by overnutrition to increase the quantity of the genuine energy-consuming protoplasm of the cells, we should be able to increase the oxygen consumption of the body proportionately. In the individual utilized in the experiment of Mayer, the consumption of oxygen per minute, however, was only increased from 222.4 to 226.1 ccm at a body weight of from 56 to 57 kg, to 234.1 ccm at a body weight of from 68 to 69 kg.

This small increase in the oxygen consumption is readily explained by the increase in weight, and this increase is strikingly small. Calculated per kilo of weight, the consumption of oxygen actually decreased; for in the beginning it was 3.987 ccm pro kg a minute; at the end 3.373 ccm. One is therefore justified in formulating the conclusion, a careful justification of which need not be attempted in this place, that the accumulated albumen is not concerned in the process of internal respiration, but possesses a different dignity from the protoplasm that was originally present in the body.

The conclusions, therefore, that can be drawn from the first and the second observations coincide, and it appears that my original hypothesis, that bestowed upon the albumen that was accumulated by overnutrition merely the significance of passive reserve material and not the importance of active protoplasm, is hereby strengthened and corroborated. From all that has been mentioned above, therefore, we are not justified in concluding that by overfeeding alone - without the co-operation of other factors - a material increase of "flesh" (genuine breathing protoplasm) can be forced.

The real "accumulation of flesh" seems to be dependent on altogether different factors and seems to presuppose a specific predisposition on the part of the organism to accumulate flesh. We find a ready tendency to the increase of flesh in:

1. the growing organism.

2. during convalescence, that is, after a certain amount of albumen has been previously sacrificed by disease or by inadequate nutrition.

3. in muscles (and glands) that are stimulated to greater activity by gradually increasing and systematically carried out exercise of their function (labor hypertrophy).

Relative to points 1 and 3 there are exact metabolic investigations to prove their correctness. It was found that with an increasing accumulation of nitrogen the consumption of oxygen increased, a fact that could not be determined in the fattening experiment of L. Mayer. Relative to point 2, a number of experiments have also been performed, but they do not suffice to give us a clear conception in regard to the intensity and extent of the flesh accumulation and the increase in the consumption of oxygen that takes place. I am just about to undertake a study of this character myself.

If one or the other of the three above mentioned factors is operative the tendency to an accumulation of flesh becomes extraordinarily marked; in fact, this tendency becomes so irresistible that the accumulation of flesh may even proceed under unfavorable conditions of nutrition. I have already mentioned that in individuals convalescing from certain diseases albumen may accumulate, even though these individuals remain undernourished. The growth of children also may become retarded by undernutrition, but not completely arrested. They do not gain in weight and remain horribly emaciated, but the growth of the body nevertheless indicates with certainty that albumen is being retained and protoplasm stored. If anyone still maintains that by over nutrition muscle, blood and glandular tissue can be built up, then he should become convinced of the futility of this argument by the daily experience that by overnutrition alone an individual can be made fat but can never be made an athlete.

We must further learn to realize that while fattening cures may also be of benefit for the development of the body musculature their action is altogether indirect. The first step is an increase in the reserve material (glycogen, fat, albumen inclosures in the cells) that the organism stores. The musculature, provided favorable factors co-operate, can then draw from these accumulated reserves the material that it requires to promote actual growth of muscle tissue. Up to a certain degree it lies in our power to create suitable factors that can become operative toward producing this result. In other words we must combine, as far as that is possible, muscular exercise, carefully in the beginning and gradually increasing, with overnutrition.

Inasmuch as I am expressing such unfavorable judgment in regard to the immediate effect of overfeeding upon the increase of protoplasm, the question might very justly be asked: why then undertake a fattening course at all, if the fat that accumulates is of very little value; why not from the beginning exercise and train?

To this query one must reply that objections of the kind just formulated go much too far and do not harmonize with practical experience. Even under unfavorable conditions of nutrition the protoplasm in an emergency can develop and grow, although not very efficiently. The protoplasm of the body can only develop in an efficient manner and reach the optimum that it was intended to reach by heredity and by the individual laws of growth if a certain surplus of nutrition is at its disposal. Hence it is beneficial, not only as far as the accumulation of adipose tissue but also as far as the development of the cells is concerned, to put forward every endeavor to place a poorly nourished organism into conditions of better nutrition. A muscle that is starving does not become strong, or at all events the strengthening process remains slow and does not reach its maximum.

Certain factors other than the lack of reserve material can prevent this development, as, for instance, the co-operation of certain toxic agencies. We know that numerous pathogenic micro-organisms and malign tumors are capable of producing toxins that act as so-called "protoplasmic poisons," and we also know of a large number of other organic and inorganic poisons that possess the same property. So long as protoplasmic poisons of this kind continue to circulate in the organism, the development and growth of the cells is seriously impaired; and all known empiric and biologic laws would be violated if one were to attempt by forced feeding or by training to increase the flesh of a typhoid patient or of a phthisical individual with fever.

The history of therapeutics unfortunately reveals many errors of this character, all amounting to this, that the factors that are really important in the construction and the destruction of the tissues are underestimated, while at the same time, the futile attempt is made to influence the growth of the tissues by introducing substances into the organism contained in these tissues. On this basis iron was prescribed in chlorosis, because an impoverishment of the organism in iron was assumed and considered to be the cause of the deficient formation of haemoglobin. By the merest chance the correct therapy was discovered in this particular instance, although the underlying idea was wrong. Iron must be considered to be merely an irritant of the bone marrow, and numerous other substances that have no relation whatsoever to the haemoglobin molecule act in precisely the same way, for instance, arsenic. Manganese also, as well as very minute quantities of copper and certain other non-medicinal measures exercise the same effect upon the bone marrow in chlorosis.

In the same sense calcium salts were administered in rachitis and in osteomalacia, of course without success; for there is never a lack of calcium in the food, especially not if cow's milk, which is very rich in calcium, is taken. The deficient assimilation of calcium or in another sense the decalcification of the organism is in reality dependent upon a disordered function of the bone cells, and an excess of calcium does not correct this perversion. The idea of strengthening a neurasthenic individual by the administration of lecithin - "the specific pabulum of the nervous substance" as one advertisement claims - is equally irrational. An ordinary mixed diet, especially if it contains 1 to 2 eggs, incorporates more assimilable lecithin than is required by the whole organism. The same criticism can be formulated in regard to the use of so-called physiologic salts that are being sold in manifold combinations and under a great variety of trade-marks.

All these and many other similar prescriptions are altogether lacking in true tissue-building power. The same applies to so-called fattening foods. The regulatory energy of the cells that is expended in the direction of promoting their growth always enters into the equation. One is capable by undernutrition to paralyze this power, but one is capable only to a very moderate degree of increasing it by overnutrition; in fact, it is quite probable that this power cannot be increased above the point that it would attain when the organism is receiving its proper "maintenance diet."