426 Influence of Inanition on Metabolism. 



from 650 to 745 grams. On the second day there is much less variation, the 

 minimum and maximum being 618 and 665 grams. The difference between 

 the lowest and the highest amounts on the third day is 90 grams, and on the 

 fourth day about 100 grams. 



In general, as the fast progresses, there is a diminution in the amount of 

 water vaporized. This is especially noticeable in the longer fasts with S. A. B. 



The absolute amounts of water excreted in the respiration and perspiration 

 are on the whole considerably smaller than those usually found with resting 

 subjects. For example, in the numerous rest experiments with food made in 

 this laboratory and previously reported, the lowest amount of water of respira- 

 tion and perspiration recorded is 697 grams 103 with E. 0. and the highest 

 amount is 1212 grams with the same subject. The average of all the rest 

 experiments gives a water excretion from lungs and skin of 935 grams. 1M 



The possible factors affecting the elimination of water-vapor are the absolute 

 amount of water in the body, including the drinking-water, the relative 

 humidity of the air in the respiration chamber, and the muscular activity of 

 the subject. 



Ratios between the water of respiration and perspiration and amounts of 

 drinking-water. The ratios between the water in the urine and the water con- 

 sumed have received special discussion on page 348. It was there seen that 

 while, in general, large amounts of drinking-water were accompanied by large 

 volumes of urine, there is no definite ratio between the volume of urine and the 

 volume of water consumed. Especially is this the case in experiments in which 

 very small volumes of water were taken. The effect of the ingestion of large 

 quantities of water on the elimination of water-vapor can be studied by means 

 of the data obtained in these experiments, since the amount of water consumed 

 each day, as well as the water of respiration and perspiration, was accurately 

 measured. The ratios between the water of respiration and perspiration (table 

 218) and the amounts of drinking-water, as recorded in column a of table 

 193, have, therefore, been computed. 



The results show widely varying ratios, the lowest being that for the third 

 day of experiment No. 73, namely, 0.218, i. e., for every 1000 grams of water 

 consumed there were but 218 grams of water of respiration and perspira- 

 tion. The largest ratio is that of the first day of experiment No. 89, namely, 

 7.121. On this day the subject consumed an unusually small amount of 

 water, i. e., 115.1 grams, while the water of respiration and perspiration was 

 820 grams. 



The ratios in the experiments with S. A. B. are more nearly constant. In 

 experiment No. 71, the ratios for the 4 days are 0.618, 0.337, 0.245, and 0.348, 



10S A special experiment, in which abnormal ventilation conditions obtained, is 

 reported in U. S. Dept. Agr., Office of Expt. Sta. Bui. 175. In this experiment the 

 water vaporized from the body was 267 grams. 



104 U. S. Dept. Agr., Office of Expt. Sta. Bui. 136, p. 137. 



