524 MAINTENANCE EXCHANGE AND GROWTH 



her of calories a child must receive daily pro kilogram in 

 order to develop satisfactorily. According to Heubiier's 

 views a breast-fed child is able to store up more reserve 

 power than an artificially fed child. Extensive computa- 

 tion experiments have been carried out in the laboratories of 

 Tangl and of Zuntz ; energy observations' bearing upon food 

 requirements of the infant have been made by A. Czerny and 

 his pupils, as well as by a very large number of pediatrists. 

 Direct measurements of maintenance metabolism have been 

 carried out within the last year or two especially by Schloss- 

 mann, in Diisseldorf, by means of the above described 

 respiration apparatus with due conformity to all modern 

 requirements. The infants are quieter than one would ex- 

 pect in the respiration experiments and tolerate well even 

 rather long fasting. In this way the production of C0 2 

 and oxygen consumption were found to be dependent not 

 upon the age, but primarily upon the surface area. 22 



Laws of Growth. In addition attention has been given 

 to the application of the method of energy observation to 

 the study of growth. In a previous lecture (Vol. I of this 

 series, p. 376, Chemistry of the Tissues) reference was made 

 to the credit due especially to Tangl and his collaborators 

 for their efforts to determine the developmental work neces- 

 sary to the 'building up of the embryo. 



In relation to the growth of the child, C. Oppenheimer 

 was the first to call attention to the fact that if the acces- 

 sions in weight of breast-fed children of even age be com- 

 pared, there will be found a direct proportion to the amount 

 of milk ingested. Later on it was shown in Graham Lusk's 



22 Literature upon Energy Computation in the Child : L. Langstein, Ergebn. 

 d. Physiol., 4, 851-890, 1905; A. Czerny and F. Steinitz, Handb. d. Pathol. d. 

 Stoffw., 2d ed., 1, 441-445, 1907; E. Mtiller (Zuntz's Lab.), Biochem. Zeitschr., 

 5, 193, 1907; F. Tangl (Budapesth), Pfliiger's Arch., 104, 453, 1904; M. Rubner 

 and 0. Heubner, Zeitschr. f. exper. Pathol., 1, 1, 1905; P. Reyher (Berlin), 

 Jahrb. f. Kinderheilk., 61, 553, 1905; A. Schlossmann and H. Murschhauser 

 (Diisseldorf), Biochem. Zeitschr., 26, 14, 1910. 



