222 Metabolism of Healthy Max. 



dioxide is reported. There are variations from 2.76 to 4.18 in the values for 

 oxygen as may be seen by examining the table. The average of all the experi- 

 ments showed 3.58 calories of heat liberated for every gram of oxygen absorbed, 

 a value in all probability somewhat higher than normal since a diet of pure 

 starch would require but 3.55 calories per gram of oxygen. 



The indications are that the diets in these experiments were largely carbo- 

 hydrate in nature, a conclusion at variance with the value found for the average 

 respiratory quotient. The discrepancies can readily be assigned to difficulties 

 attending the oxygen determinations in experiments as short as were the ma- 

 jority of the experiments from which the values in tables 73 and 89 were drawn. 



The determinations of the carbon dioxide are not open to the error that is 

 liable to occur in the determination of oxygen for short periods, and hence are 

 on a more accurate analytical basis. The number of calories of heat accom- 

 panying the production of one gram of carbon dioxide varies widely, also, with 

 different individuals, the highest being 3.23 with the subject F. E. E. and the 

 lowest 2.61 with the subject F. G. B. The average of all the subjects showed 

 2.94 calories accompanying the production of 1 gram of carbon dioxide. These 

 values are all within reasonable limits when compared with those given in 

 table 87. 



Comparison of calorific equivalents of oxygen and carbon dioxide during 

 sleep, waling hours and for 24- hours. A stricter comparison of the oxygen 

 and carbon-dioxide calorific equivalents may be made when we consider those 

 subjects that remained in the respiration chamber for not less than 24 hours. 

 During this time there is a sleeping period, which is sharply characterized 

 between 1 a. m. and 7 a. m., and a waking period from 7 a. m. to 10 or 11 p. m. 

 We have also the data for the whole 24 hours. These results have been collected 

 and presented in table 93 herewith. Furthermore, the results are so collected 

 that the period of sleep follows immediately the period of waking hours in all 

 cases, since there is the strictest comparison between the two. In so doing, 

 certain of the values in the sleeping period may appear to vary from those pre- 

 viously recorded in table 91. Considering the calorific equivalent of oxygen, it 

 can be seen that the average value during the waking hours from 7 a. m. to 10 

 or 11 p. m. is 3.34 calories; during sleep, 3.38 calories; and during the 24 hours, 

 3.37 calories. The calorific equivalent of carbon dioxide during waking hours 

 is 2.97 ; during sleep, 3.08 ; and during the 24 hours, 3.00 calories. With regard 

 to the calorific equivalent of oxygen it can be seen that the values are remark- 

 ably uniform for all subjects. Thus during the waking hours, the minimum is 

 3.22 calories and the maximum, 3.52 calories. Omitting the value for H. F., 

 3.52 calories, practically all the results are within 2 or 3 per cent of the average. 

 During sleep the calorific equivalents ranged from 3.13 to 3.58 calories. 



Of the greatest importance is the comparison of the oxygen calorific equiva- 

 lent for different individuals for experiments of 24 hours' duration. During 

 experiments of this length of time, most of the errors incidental to the determi- 



