BASAL METABOLISM. 99 



results obtained with over 30 subjects are thus available for compari- 

 son. With several subjects the experiments were made at intervals 

 during a period of five or even six years, but with the majority they 

 were made in a period of approximately two months or even two weeks. 

 An abstract of similar data, which includes nearly all of the subjects 

 with whom we are dealing in this publication, has been given in a 

 previous paper from this laboratory. 1 Emphasis was there laid upon 

 the variations in the average maximum values for the oxygen con- 

 sumption, using the average minimum value for a basis. Inasmuch 

 as it is important to note the actual variations which may be observed 

 in a long series of experiments of this kind, the data will be considered 

 in more detail in this publication. 



As it would be impracticable to print all of the material obtained, 

 three typical subjects have been selected and the carbon-dioxide pro- 

 duction and oxygen consumption per minute for the individual periods 

 with these subjects have been tabulated. The data for the other 

 subjects are given in abstract. In the tables showing the detailed 

 results, the day has been subdivided into half-hour periods and the 

 data for the individual 15-minute periods of the experiment placed 

 according to the time the observations were made. The values given 

 under "first period" commonly represent those obtained in the experi- 

 mental periods which occurred between 8 and 8 h 30 m a. m. At the 

 bottom of the tables are given the average values for each 30-minute 

 period throughout the series, thus indicating the average course of the 

 metabolism throughout the day. The minimum and the maximum 

 values for each period are also given and the mean variations of the 

 individual values from the averages. In the extreme right-hand 

 column the averages for the individual experiments are placed, show- 

 ing the course of the metabolism throughout the months or years of 

 the study. 



In studying the results given in these tables, emphasis should be laid 

 only upon the average values and no particular significance given to 

 single values like the maximum and minimum data. This is in accord- 

 ance with the custom of this laboratory, as such values are liable to 

 technical errors and physiological variations which must necessarily 

 creep into experiments as complicated as these. The average values for 

 the day are olrawn from at least two results and usually three or more, 

 while those for consecutive periods are computed from 5 to 42 periods. 

 It should furthermore be remembered that the data for the oxygen 

 consumption give a more logical basis for discussion than those ob- 

 tained for the carbon-dioxide elimination. This is due to the remark- 

 able influence upon the carbon-dioxide production of the character of 

 the previous diet, 2 the large variations in the calorific equivalent of 



Benedict, Journ. Biol. Chem., 1915, 20, p. 263, table 4. 

 2 Benedict and Higgins, Am. Journ. Physiol., 1912, 30, p. 217. 



