Introduction. 11 



virtue of noticeable changes in body-temperature. A rise in body-temperature 

 of 1 in a body weighing 70 kilos results in a storage of about 60 calories. 

 It is necessary, therefore, to know the body-temperature with great accuracy, 

 and this is measured by means of an electrical-resistance thermometer placed 

 in the rectum. The body-weight is determined from time to time by scales 

 outside of the chamber, from the platform of which is suspended the chair in 

 which the subject sits inside the chamber. 



SCOPE AND ROUTINE OF PRESENT SERIES OF EXPERIMENTS. 



The experiments here reported are of widely varying nature. The majority 

 of them lasted but 6 or 7 hours and were made during the daytime. In a few 

 others, the subject remained inside of the chamber some 24 or more hours. 

 In the long experiments, the subject usually entered the chamber the night 

 before the experiment proper began. As a result of many years' experimenting, 

 it has been deemed advisable to begin the experimental day at 7 a. m., at which 

 time it is assumed that the body-temperature, general activity, and mass of 

 body-material remains more nearly the same from day to day than at any other 

 hour. After entering the chamber, the subject goes to bed and is not allowed 

 to rise until the next morning a few moments after 7 o'clock. The greater 

 part of the day is spent in sitting in the chair reading or writing, or occasion- 

 ally lying on the bed, and where food is eaten it is taken in regular periods 

 and in regular amounts. The urine and feces are properly collected and 

 analyzed. In the short experiments, where only data regarding normal waking 

 metabolism were desired, it was deemed unnecessary to have the subjects 

 remain so long a period inside of the chamber, and the plan of experimenting 

 was so modified as to enable us to secure short experiments with a number of 

 subjects rather than a long experiment on one subject. In these short experi- 

 ments the subject entered the chamber in the early forenoon and as soon as 

 thermal equilibrium was established in the chamber the experiment proper 

 began. In a number of experiments food was given during the experiment 

 itself; in others no food was taken. In the detailed statistics of the experi- 

 ments will be found all the data regarding the diet, the time at which food 

 was taken, the muscular movements, and similar physiological data. 



Study of nitrogen balance in these experiments impracticable. While it may 

 seem somewhat surprising that in the discussion of any series of experiments 

 intended as a study of the normal metabolism of man, the data regarding the 

 nitrogen output in urine and feces are not included, nevertheless it has been 

 found that unless the subject remains upon a relatively constant diet for at 

 least 3 or 4 days previous to the experiment the nitrogen elimination during 

 an experiment of only 6 to 8 hours' duration has relatively very little sig- 

 nificance. Indeed, the common assumption that nitrogen in urine represents 

 the disintegration of an equivalent amount of protein during the time of 



