22 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



is not true, since all humans lie quietly in bed some 8 or 10 hours 

 each day. On the other hand, life in a respiration chamber is not 

 normal, for the experimental periods of Sonden and Tigerstedt, and 

 especially the 22-hour periods of Rubner, do not represent normal 

 conditions in a child's daily existence, when he is living a more or less 

 active and unrestricted life. This may be illustrated by comparing 

 the daily requirement of Rubner's boys, i. e., about 1,700 calories, 

 with the food intake of the boys in Gephart's study 1 at St. Paul's 

 School in Concord, New Hampshire, which approximated 5,000 

 calories. An attempt to study the requirements of the day as a 

 whole by a 22 to 24 hour sojourn in a respiration chamber would 

 therefore be a great mistake and a return to the standards of 25 years 

 ago. 



The only logical method for determining the child's energy require- 

 ments for a day's existence is to obtain, first, the requirement for 

 maintenance (the basal metabolism); second, the additional energy 

 required for sitting in a chair reading or studying; third, the energy 

 requirement for walking; and fourth, that for running and playing 

 or at severe work. With adults we already have much information as 

 to the energy requirements for the first three, and may later be able to 

 determine the enormously variable factors for the fourth requirement. 



In criticizing the experiments of Sonden and Tigerstedt and others 

 using a large respiration chamber, one should bear in mind the fact 

 that they were not planned to study the so-called basal metabolism, 

 for at that time the conception of basal metabolism was but imper- 

 fectly outlined in the minds of the investigators. Furthermore. 

 Sonden and Tigerstedt definitely claim that their results were not 

 rninimum or basal. Except when the data were determined during 

 deep sleep, the basal metabolism for these subjects was not deter- 

 mined, for young children as well as adults were studied under con- 

 ditions of only comparative and not complete muscular repose and 

 during the process of digestion. For a study of the general question 

 as to whether or not there is an alteration in the metabolism per unit 

 of weight or per unit of surface with individuals of different ages, it 

 may be that the experimental procedure used by them would be 

 justifiable, namely, a study of all subjects under presumably like 

 (though certainly not basal) conditions. 



Similarly, Rubner's experiments were made to determine the total 

 metabolism during the 24-hour period and thus could not be used 

 for basal comparison. In Rubner's observations there was a con- 

 siderable amount of sleep, which tended to compensate in part, at 

 least, for the excess activity during the waking hours. Had Rubner's 

 results been so published as to permit the computation of the values 



1 Gephart, Boston Med. and Surg. Journ., 1917' 176, p. 17. 



