82 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



\ 



days. While these values do indicate, therefore, a constancy in the 

 metabolism for periods of this length, they give no evidence as to 

 the possibilities of variations from period to period, such as those shown 

 in tables 23, 24, 25, and 26. 



In considering the values for the metabolism given in these basal 

 tables, it should be remembered that the subjects were allowed the 

 restricted freedom of the respiration chamber. It was impossible to 

 require them to remain absolutely quiet or to assume a definite posi- 

 tion for the period of 8 to 12 hours during which they were under obser- 

 vation. The muscular activity was kept at a minimum, however, and 

 every attempt was made to have it uniform from day to day. While 

 we believe that the values given represent a higher metabolism than 

 the strictly basal metabolism of the individuals studied i. e., the metab- 

 olism with muscular repose and without food in the stomach we feel 

 that our use of them for comparison with the results of the subsequent 

 food experiments is permissible, in the absence of less contaminated 

 data, inasmuch as the routine and degree of muscular activity on the 

 food days were very similar to those on the daj^s when the basal 

 metabolism was obtained. 



BOSTON CALORIMETER EXPERIMENTS (8-HouR BASIS). 



In the experiments on the 8-hour plan in Boston, both the chair 

 calorimeter and the bed calorimeter were used for measuring the 

 metabolism. In the chair calorimeter, which was the first calorimeter 

 constructed in the Nutrition Laboratory, the subject remained com- 

 fortably seated in an arm chair throughout an experiment. The total 

 volume of the air in the chamber was approximately 1,400 liters; the 

 air space and body activity were therefore much more restricted than 

 in the Middletown calorimeter, in which the chamber had a volume 

 of approximately 5,000 liters, affording opportunity for considerable 

 movement. In the chair calorimeter the water bottles and urine 

 bottles were conveniently placed near the subject and it was unneces- 

 sary to rise from the chair for their use ; there was, however, some minor 

 muscular activity, such as the motions accompanying the reading of 

 a book, and similar movements. The actual activity in the chair- 

 calorimeter experiments was very considerably less than that in the 

 calorimeter experiments in Middletown, save when the latter experi- 

 ments were made during the periods from 11 p. m. to 7 a. m. with the 

 subject asleep in bed. 



The chamber of the bed calorimeter was even smaller than that of 

 the chair calorimeter, being approximately 950 liters in volume. The 

 subject lay upon a cot and it was impossible for him to sit up or to 

 move very much except to turn the body from side to side. The 

 food aperture was never opened during an experiment. Occasionally 



