102 METABOLISM AND GROWTH FROM BIRTH TO PUBERTY. 



dren. The data for this child are given in table 25. For complete 

 record it has been necessary to include data for the body-weight, height, 

 age, the estimated energy of food taken prior to the experiment, the 

 length of time elapsing between the taking of food and the beginning 

 of the first observation, the carbon dioxide produced per hour in the 

 several successive experimental periods, the respiratory quotient, the 

 average pulse-rate for each period, the relative activity as estimated 

 from the kymograph records, notes as to whether the subject was 

 asleep or awake, the total heat production (computed) per 24 hours, 

 and likewise the heat produced per kilogram of body-weight per 24 

 hours and per square meter of body-surface per 24 hours. The 

 relative activity is expressed on an arbitrary scale ranging from the 

 greatest degree of repose (I) to the greatest activity (VI). The body- 

 surface was determined by the Du Bois linear formula and direct 

 measurements made upon the subject for practically every observation. 

 As has already been pointed out, while ideally the observations should 

 have been made without food in the stomach, this is an abnormal 

 condition for young children. It will be noted that as the child grew 

 older the length of time between the feeding and the beginning of the 

 first experimental period lengthened, until it was finally between 4 

 and 5 hours long. 



As indicated in the outline of the description of the experimental 

 procedure, the carbon-dioxide production was directly measured for 

 each experimental period. These periods were approximately 30 

 minutes hi length. As it was impracticable to determine the oxygen 

 consumption in periods as short as this, due chiefly to the difficulty 

 in obtaining accurate measurements of the average temperature of 

 the air inside the respiration chamber, we determined only the total 

 consumption of oxygen for the entire sojourn of the child inside the 

 chamber. Thus for four experimental periods, each of 30 minutes, 

 the oxygen consumption would be determined only for the full 2-hour 

 period of the experiment, and this total amount used in the computa- 

 tion of the respiratory quotient. 



In most of the studies there was a preliminary period in which 

 various adjustments were made and in which the oxygen consumption 

 was not determined. During the preliminary periods the amount of 

 carbon dioxide produced was almost invariably larger than in later 

 periods, this being due to the activity of the child, who was frequently 

 awake at this time. The carbon-dioxide production for these periods 

 is likewise recorded in table 25, but the measurements of the oxygen 

 consumption, which were used for computing the respiratory quotients, 

 were made only in the main periods of the observation, i. e., those 

 represented by the values inclosed in brackets. It occasionally hap- 

 pened that, even during the preliminary period, the carbon-dioxide 

 production was at a minimum. Thus, on April 2, 1917, the carbon- 



