The so-called respiratory quotient* was the same in both cases, in 85 Infant 2 = 0.SS (for the figures of the fraction see line for 0 in 96.2 2.5 Table 7); in Infant 1, 10 - = 0.90 (see explanation given above). 114 From this the conclusion is drawn, that a relatively large amount of carbohydrates (lactose in this case) was oxidized in both cases. Infant 2, might have registered a fair gain in spite of the insufficient amount of food, if it had been less restless and had cried less. Lnder the prevailing conditions the observers calculated a slight gain in body substance with a loss of sonic body fat. Such ptsculiar conditions of growth as these are occasionally observed in children who do not receive a sufficient amount of food.
Fig. 56 illustrates such a case. This child suffered with a geo graphical tongue from the ninth month to the second half of the fifth year and therefore did not eat sufficiently. Attacks of sickness can be recognized by the occasional losses in body weight. This boy received the breast for three months and the bottle up to nine months, with good result, before the affection of the mouth influenced his gain in weight.
The growth in length (in the skeleton and partly in the muscle) even exceeds the normal from years on, while the gain in weight re mains far below the normal and does not begin to rise until late. There is every reason for assuming that the chemical composition of the body is normal, with exception of the fat. The gain in proteid and ash there fore was about normal while the gain in fat was abnormally low.
It would be possible to give the balances of metabolism obtained by the statistical method for each period of infancy (with the exception of the first week of life, which will be considered separately) for the breast-fed infant as well as for the one artificially fed. But the one example will suffice. On this basis, the significance of the total amount of food and of the individual constituents of the food may be learned, with special reference to the life of the infant. A few more data con cerning the gaseous metabolism at different periods may be cited here.
The variation in the amount of insensible perspiration is considerable; for instance, a young infant eliminates 2 to :3 Gin. (:30-45 grains) if rest ing well, but if very restless 10 to 15 Gm. (150-225 grains) per hour.
Formerly, an excessive influence on the processes of the metabo lism was attributed to the growth of the infant, and it is generally thought that infants and children require relatively a large amount of nourish ment, "because they grow so But this is not well founded.
The daily gain of the 10-week old infant of Table 7 was only 25 Gm. (6 drams). equal to 0.5 per cent. of its body weight; while at the end of the first month, which is the time of the most active absolute and relative growth, the average daily gain is 30 Gin. (S drains) or just about 1 per cent. of the body weight.
At the present day, in the light of the theory of energy, it is not conceivable how' a gain of only 1 per cent. or 0.5 per cent. should exer cise a leading influence on the required amount of food. Table 7 (Infant 1) demonstrates that not less than 85 per cent. of the ingested organic substance is oxidized and eliminated through the skin and lungs in the form of carbon dioxide and water. This means that more than SO per cent. of the introduced energy is thus eliminated, while only about 9 per cent. remains in the body to constitute the gain. In the balance of Infant 2 a gain in body substance took place, although the food was insufficient and the balance of energy was negative. Such observations and considerations enforce the conclusion, that the relatively great food requirement must be due to peculiarities of the infant's body. The growth must be ascribed especially to those peculiar forces which, after being set in motion by fertilization, cause the segmentation of the ovum and the whole further development Of the embryo. These forces attract substances to the growing cells of the body with soch power thai growth can proceed even when at the same time body fat is decomposed. It necessary to find out these peculiarities of the child's body. According to a known law of stereometry, the smatter of two bodies of similar form has relatively the larger surface, -that is, in relation to its cubic content, or to its weight if the two bodies are composed of the same substance. In the latter case it may be stated that the surface of 1 kg. of the small body is twice or three times as large as that of I kg. of the larger body. The consequence is that I kg, of the small body in the saute time and under the same conditions can give of! (or take in) twice or three times as much heat as 1 kg. of the large body. This can he readily illustrated with an example taken from daily experience: Suppose a hot water heater contains a kg. water and has a smooth sur face of square decimetres. If the surface is increased to 3L square decimetre by channeling, the amount of heat given off under otherwise equal conditions will be three times as great as that given off from the smooth surface.