92 VITALITY AND EFFICIENCY WITH RESTRICTED DIET. 



volume of air. Such computations have been made for 14 experiments 

 in which from 198 to 272 c.c. of oxygen were used and with temperature 

 fluctuations ranging from 3° to 19° F. It was found that the difference 

 as a result of making this reduction corresponds to +1 c.c. of oxygen 

 for each degree Fahrenheit of the rise in temperature during the meas- 

 urement. It is therefore justifiable, for the sake of simplicity, to make 

 an arbitrary correction by adding 1 c.c. of oxygen for each degree of the 

 rise in temperature of 7° F. This gives a value of 207 c.c. of oxygen 

 per minute consumed during the period of 15 minutes and 16 seconds. 

 The same method is followed in calculating the oxygen consumed 

 during the intermediate measurement, i. e., period la. The agreement 

 of the two measurements is excellent, 207 and 206 c. c. oxygen per 

 minute. 



PRACTICAL USE OF THE APPARATUS. 



From the foregoing description it will be seen that this apparatus dis- 

 penses with gas analysis and weighings. By reading the millimeter 

 scale indicating the height of the spirometer bell, the thermometer in 

 the top of the spirometer, and the barometer, we may obtain all the 

 data required for rapidly computing oxygen consumption and heat 

 production. The apparatus is designed particularly for the determina- 

 tion of the oxygen consumption, with special reference to clinical 

 application. It can not be used for the determination of the respira- 

 tory quotient as a substitute for either the respiratory-valve method 

 outhned by Dr. Carpenter (a closely fitting mask, Tissot valves, a 

 carefully calibrated spirometer, good gas-analysis apparatus, and a 

 good gas analyst) or the perfected form of the clinical respiration 

 apparatus developed in the Nutrition Laboratory.^ The portable 

 respiration apparatus has, however, the advantages of portability, 

 simplicity, and rapidity of operation, with a degree of accuracy in 

 the determination of the oxygen consumption to meet the needs of 

 practically all scientific work. It was particularly adapted for use 

 in the low-diet research for simultaneously measuring the basal metab- 

 olism of seven young men each morning. Four of the apparatus 

 employed for these observations are shown in figure 4 in position, 

 with accompanying beds, in one of the laboratory rooms at the Young 

 Men's Christian Association College, Springfield, Massachusetts. 

 GROUP RESPIRATION APPARATUS. 



While the universal respiration apparatus in its various forms per- 

 mits the measurement of the metaboHsm of an individual, even when 

 he is working to the limit of human endurance, it is practically limited 

 to the measurement of a carbon-dioxide production not exceeding 

 2,700 to 2,800 c.c. per minute. As a matter of fact, this particular 



1 Benedict and Tompkins, Boston Med. and Surg. Journ., 1916, 174, pp. 857, 898, and 939. 



