106 Metabolism of Healthy Max. 



In collecting the experiments in this table, only those that are strictly com- 

 parable as regards the muscular activity, time of day, digestion, etc., are 

 brought together, and certain of the experiments presented in the preceding 

 section are admirably suited for a discussion of constancy in metabolism. It 

 has been deemed advisable likewise to include previously published experiments 

 with the same individual so far as the conditions are equally comparable with 

 the conditions of those already included. Many of these earlier experiments 

 were designed for an entirely different purpose and only sections are used 

 for comparison here; thus, as regards the sleeping periods the published ex- 

 periments were inanition periods of 24 hours, with a preliminary night fol- 

 lowing the ingestion of food. These earlier results have given an added value, 

 for they show in several instances, at least, the metabolism of the same indi- 

 vidual under like conditions with an interval of several months. The last 

 three experiments presented in the table were made with a woman subject. 

 In this collection of comparisons it is aimed to state the muscular activity, 

 whether the subject was awake or asleep, with or without food, and the time 

 of day, together with the carbon dioxide excreted, the oxygen absorption, and 

 the heat production per hour. While, for the most part, the duplicate experi- 

 ments covered the same period of the day, sometimes this was not exactly the 

 case, but such instances, because of the muscular activity usual inside the 

 respiration chamber, may be considered as not affecting the respective com- 

 parisons. The table is not designed in any way to throw light upon the com- 

 parative metabolism of different individuals or for the study of the differences 

 in metabolism of the same individual under different conditions, but merely 

 to show the constancy of metabolism in the same individual under similar 

 conditions. The data are given only as average quantities per hour for the 

 whole experiment, and for any further details one must refer to the statistics 

 of the experiments. 



An examination of the figures in this table shows that there is a striking 

 uniformity of metabolism in the experiments with the same individual under 

 like conditions of bodily activity. For example, it rarely happens that in 

 two experiments with the same individual and a given condition, the carbon- 

 dioxide excretion varies by more than 2 grams per hour, and in many instances 

 the agreement is complete. 



Similar uniformity is shown with regard to the oxygen consumption in 

 different experiments with the same individual. As has been pointed out in 

 many publications, the determination of oxygen is very difficult, arid hence 

 more reliance can be placed upon the greater accuracy and uniformity of the 

 determinations of carbon dioxide. However, we believe that the oxygen de- 

 terminations here given represent as truly as any values heretofore presented 

 the oxygen consumption of individuals under the conditions obtaining in these 

 experiments. The results show conclusively that with the same individual 

 under like conditions of activity the oxygen consumption is relatively con- 



