246 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



ments of the respiratory exchange, the oral temperature of the subject 

 was taken with a standard cUnical thermometer. These records were 

 made simply to eliminate the possibility of measuring the gaseous 

 exchange when the subject was in a slightly febrile or febrile condition, 

 and not with a view to determining the physiological temperature, for 

 as is well known, mouth temperatures have no definite physiological 

 value. 



Throughout the entire series abnormal temperatures were rarely 

 found. Occasionally slightly febrile temperatures were noted when 

 the subject was suffering from a cold; under these conditions the 

 gaseous metabolism was not measured. With Spe abnormal body 

 temperatures were recorded for a number of days prior to his leaving 

 for home in consequence of suspected typhoid infection. 



RECTAL TEMPERATURE MEASUREMENTS. 



In contrast to the temperature measurements taken in the mouth, 

 the temperature measurements made in the rectum were of true physi- 

 ological significance. These were obtained at the end of the night ex- 

 periments with the respiration chamber in Boston and just before the 

 subject arose in the morning. For this purpose 12 accurate clinical ther- 

 mometers were used; all of these thermometers had previously been 

 carefully calibrated with a standard Richter thermometer. Owing to 

 the darkness of the chamber it was impossible for the experimenters 

 to insert the thermometer personally. After the bulbs of the thermo- 

 meters had been coated with vaseline, each man was instructed to 

 insert a thermometer more than half its length in the rectum. Inas- 

 much as the men were an unusually intelligent group and thoroughly 

 appreciative of the importance of the experiment, we have reason 

 to believe that the thermometers were in all instances satisfactorily 

 inserted and that the temperature recorded may be taken as a true 

 measure of the rectal temperature of these men. After the thermo- 

 meters had been removed they were carefully read and checked by a 

 second person before the records were finally made. 



The special advantages of taking rectal temperatures under these 

 conditions were, first, that the subjects had all received a constant 

 standard meal at 5 p. m. the night before. Furthermore, they were 

 lying on the beds inside the chamber for not less than 7 to 8 hours 

 prior to the temperature record; during this time the enviroimaental 

 temperature was almost absolutely constant, and, except in very rare 

 cases, the subject slept the entire night. Finally, as stated above, 

 the temperatures were taken the first thing in the morning, before 

 activity of any kind was engaged in. The conditions thus seemed to 

 be ideal for obtaining true records of the rectal temperature. As with 

 a number of our observations, the records of the rectal temperature 

 under these conditions were not begun until November 11; hence 



