BASAL METABOLISM. 53 



gaseous metabolism and energy transformations during prolonged 

 fasting would be of fundamental importance, and furthermore, that 

 after such a fast ideal conditions would be present for studying the 

 superimposed factor of the ingestion of food. 



These fasting experiments varied in length from 1 to 7 days. To 

 obtain like activity in the basal periods and in those following food, 

 it was the custom to watch the subject continuously during the fasting 

 period and to record each movement. A program was then prepared, 

 duplicating in every detail the movements of the fasting period, and in 

 the comparison food experiment the subject was requested to follow 

 this program faithfully. It was assumed that the narrow confines of 

 the chamber and the routine program would so restrict the muscular 

 activity of the subject on the food days that the degree of intensity 

 would approximate that of the fast days. 



The experiments as planned included one or more periods of observa- 

 tion when the subject was lying, presumably asleep, inside of the respi- 

 ration chamber; it was believed that these periods would give ample 

 opportunity for studying the most quiet metabolism of the fasting 

 individual. At that time evidence was not secured regarding the con- 

 stancy in the degree of muscular repose during these sleeping periods, 

 aside from the reports of the subjects themselves as to their condition 

 during the night. It was almost invariably reported that the subject 

 slept moderately well. Certainly the men did not at any time leave 

 the couch and the muscular activity, if there were such, did not cause a 

 sufficient heat disturbance to attract the attention of the physical 

 observer. 



The influence of the ingestion of food was determined by noting the 

 basal metabolism in 24 hours without food and comparing it with the 

 metabolism during a 24-hour period in which a particular diet was 

 ingested, the increment in the metabolism showing the increase due to 

 the ingestion of the food. 



CRITIQUE OF 24-HOUR METHOD. 



This method of determining the metabolism in 24-hour periods has 

 been regularly employed by many investigators. It was used by 

 Johansson and his associates 1 in the Stockholm laboratory in consider- 

 ing the effects of food following a 5-day fast. In Johansson's experi- 

 ments the food ingestion immediately followed or immediately preceded 

 the fasting days. In the experiment of 5 consecutive days reported 

 by Rubner, 2 on the first day there was hunger and rest, on the second 

 protein diet and rest, on the third protein diet and work, on the fourth 

 sugar diet and rest, and on the fifth sugar diet and work. 



'Johansson, Landergren, Sonden, and Tigerstedt, Skand. Arch. f. Physiol., 1897. 7, p. 20. 

 "Rubner, Sitzber. K. Preuss. Akad. Wiss., 1910, p. 316. 



