74 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



introduced may amount to a considerable percentage of the whole 

 increment. 



With large increments this possible difference in conditions would 

 of course have less significance than with small increments. Con- 

 sequently, while both the 24-hour and the 8-hour basal units permit 

 reasonably satisfactory measurements of large increments in the metab- 

 olism as a result of the taking of food, they are open to very serious 

 objection when used for the measurement of small increments. 



DISCUSSION OF RESULTS OF 8-HOUR EXPERIMENTS WITHOUT FOOD. 



The 8-hour experiments were made with the respiration calorimeters 

 at Wesleyan University, Middletown, Connecticut, and the Nutrition 

 Laboratory, Boston, Massachusetts. Inasmuch as the Boston 8-hour 

 experiments differed somewhat in plan from those made in Middle- 

 town, the two groups of experiments will be discussed separately. 

 Those carried out at Wesleyan University will first be considered, not 

 only because they are first in chronological order, but also because the 

 apparatus used and general technique, other than duration, were like 

 those of the 24-hour experiments which have just been discussed. 



In the collection of the data a number of basal values were secured, 

 ranging over a period of several weeks or months, and not infrequently 

 a year or more. Hence this collection of basal data has special impor- 

 tance as indicating the possibility of seasonal variation, and furthermore 

 as showing the probable trend of the metabolism on any given day when 

 the metabolism was measured in 4 to 6 consecutive 2-hour periods. 

 The basal metabolism experiments only will be considered in this 

 section; the results of the experiments with food will be given later in 

 the discussion of the effect upon the metabolism of different classes of 

 foods. 



MIDDLETOWN CALORIMETER EXPERIMENTS (8-HouR BASIS). 



The 8-hour plan was used successfully in a large number of experi- 

 ments at Wesleyan University in which the basal metabolism was 

 studied for approximately this period on one day and on a subsequent 

 day the metabolism after the ingestion of food was found for a corre- 

 sponding period. The increment due to the food was then determined 

 by comparing the results obtained. Uniformity in the degree of 

 muscular repose was even more important in these shorter experiments 

 than it was in the 24-hour experiments, and it was necessary to reduce 

 the muscular activity to a minimum so far as possible. 



The results of the experiments are given in tables 23 to 26. These 

 tables show the experimental day divided into 2-hour periods, the data 

 for the individual periods being placed according to the time the obser- 

 vations were made. The experiments usually began about 9 a. m., 



