PREVIOUS STUDIES OF METABOLISM OF CHILDREN. 



In considering the previous studies with children, one must differ- 

 entiate sharply between measurements of metabolism which are 

 possible only with respiration apparatus or calorimeters and the 

 computation of the energy requirement for the day from a statistical 

 study of the diets consumed by the infants or children observed. 

 The researches on energy transformation of children may be divided 

 into two classes: (1) those by the indirect method, in which a study 

 is made of the respiratory exchange by means of some form of respira- 

 tion chamber, and (2) those by direct calorimetry, in which the heat 

 output is determined with a calorimeter. 



Beginning with the calorimetric researches of Richet, a number of 

 French writers conducted researches on the metabolism of infants by 

 direct calorimetry, several of these observations being made with 

 calorimeters devised by d'Arsonval. These studies have already been 

 summarized in one of our earlier reports, 1 but they have little present- 

 day value, for the investigators disregarded the somewhat considerable 

 withdrawal of heat from the body by the vaporization of water and 

 gave no quantitative information regarding muscular activity. Fur- 

 thermore, much of the French work was done with abnormal children, 

 while our report deals exclusively with the physiology of normal youth. 



Calorimetric observations of the basal metabolism of children have 

 also been made by Du Bois and associates, which will be cited in some 

 detail later. The greater part of their computations and the deduc- 

 tions therefrom are, however, based upon indirect calorimetry rather 

 than upon direct calorimetric measurements. The observations of 

 the basal metabolism of infants made by Rowland with Lusk's calori- 

 meter, 2 an abstract of which was given in our earlier report, are, so 

 far as we know, the only successful studies of infants which have thus 

 far been made by the direct method. Practically all of the observa- 

 tions cited in the following pages, therefore, are those made by the 

 indirect method. 



Andral and Gavarret, 1843. The first experiments on children, made 

 by Andral and Gavarret, 3 although having mainly an historical 

 interest, should certainly be considered in any careful analysis of the 

 literature. Since at this early date the authors laid special stress upon 



1 Detailed references to the researches of these investigators are given in Benedict and Talbot, 



Carnegie Inst. Wash. Pub. No. 201, 1914, pp. 11 to 14. 



2 Rowland, Proc. Soc. Exp. Biol. and Med., 1911, 8, p. 63; Hoppe-Seyler's Zeitschr. f. Physiol. 



Chem., 1911, 74, p. 1; Trans. 15th Int. Congress on Hygiene and Demography, Washing- 

 ton, 1913, 2, p. 438. Cited by Benedict and Talbot, Carnegie Inst. Wash. Pub. No. 201, 

 1914, p. 22. 



3 Andral and Gavarret, Ann. d. Chim. et d. Phys., 1843, ser. 3, 8, p. 129. 



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