Kelations between Factors of Metabolism. 



205 



During 21+ hours in rest experiments. From the foregoing discussion it is 

 seen that for every 100 grams of carbon dioxide excreted during the night with 

 17 subjects, there were 140 grams of water vaporized, while during the day 

 with some 55 subjects, for every 33.1 grams of carbon dioxide excreted, there 

 Avere 38.7 grams of water vaporized, or as 100: 117. The difference between 

 these ratios is so great that it is necessary to consider the quantities for 24 hours 

 in order to have any adequate idea of the ratio of carbon dioxide eliminated to 

 water vaporized during an experimental day of 24 hours' duration. With 17 

 subjects these comparisons have been made and are given in table 84, which 

 shows the total excretion of carbon dioxide, the total water vaporized from the 

 lungs and skin, and the ratios, taking the carbon-dioxide excretion as 100. 

 This ratio varies from 100 : 103 with the subject H. E. D. to 100 : 135 with the 

 subject B. F. D. The average of all experiments showed a ratio of 100 : 114. 



Table 84. Ratio of carbon dioxide eliminated to water vaporized during 24 hours in 



rest experiments. 



Under the conditions, then, obtaining in the respiration chamber, it is rea- 

 sonably certain that for every 100 grams of carbon dioxide excreted during an 

 experiment of 24 hours' duration there will be on the average 114 grams of 

 water-vapor. Variations from this normal value are too great for one to assume 

 this as a standard factor, and consequently for experiments where the water 

 vaporized from the lungs and skin is desired, either for itself or to aid in com- 

 puting the heat transformation, the results here shown will not permit of the 

 calculation of the water vaporized from the determination of the carbon-dioxide 

 excretion. Obviously, the results here may be affected by all those factors pre- 

 viously discussed which affect water-vapor excretion, such as the ingestion of 

 food, muscular exercise, lying in bed awake or asleep, probably the temperature 

 of the human body, the temperature of the environment, and likewise the rela- 

 tive humidity of the air. 



Earlier investigations. The earliest experiments that we have been able to 

 find which permit of the comparison of the carbon-dioxide elimination and 



