116 



PHYSIOLOGY 



CHAP. 



The average increase in weight of a child during the first year 

 of life is, as will readily be seen from the above table, 18 grnis. 

 per day, varying in different weeks from 4 to 30 grms. It may, 

 therefore, be considered that during the first year of life the child 

 needs for its exchange of material per kgrm. of its body-weight 

 a daily average of 140-150 grms. of mother's milk, containing 

 2 -8 grms. of protein, 9 '5 of carbohydrate, and 5 '5 of fat, with a 

 total energy- value of 102 calories. Of course these average 

 figures may vary considerably, according to individuality, sex, 

 season of the year, and other factors less easily determined. 



The great intensity of the exchange of material in the child 

 as compared with that of the adult is especially noteworthy. 

 The amount -of protein, fat, and carbohydrate per kilo, body- 

 weight taken by the child at the breast is greater, not only than 

 that of the adult living on Chittenden's reduced diet, but also 

 of those accustomed to the generous diet of Voit, Atwater, and 

 Tigerstedt. Whereas the child at the breast utilises from 79 to 

 112 calories per kgrm. of its weight, adult Europeans and 

 Americans only utilise from 27 to 61, as will be seen by reference 

 to the tables on pages 93-94. This difference is due not only 

 to the fact that the child loses to the environment as much greater 

 an amount of heat as the surface of its body, in proportion to 

 its weight, is greater than in the adult, but also to the fact that 

 it retains on an average for the development of its body 18 grms. 

 a day of the plastic and respiratory food substances introduced in 

 the milk. 



