142 



Metabolism of Healthy Man. 



12.312 and W is the body-weight. Even calculating the results on a supposedly 

 common basis, we find variations in the amounts vaporized per square meter 

 of body-surface per hour ranging from 14 grams with H. E. D. to 29.2 grams 

 with B. N. The average value is 19.7 grams per hour. 



WATER VAPORIZED DURING SLEEP. 



During sleep when the subject is lying quietly in bed with light covering, 

 perhaps the best conditions for studying the water-vapor output obtain. In 

 the experiments reported the subjects usually went to bed at 11 p.m.; the 

 absence of muscular activity during the following 2 hours resulted in constant 

 conditions with regard to temperature and moisture inside the chamber at 1 

 a. m., and this constancy makes all such experiments more strictly comparable. 

 While, then, there are fewer subjects with whom the water-vapor output during 

 sleep has been studied, we believe that the results of experiments made during 

 this period are more comparable with each other, especially on the basis of 

 body-weight or body-surface, than with experiments made under any other 

 conditions heretofore obtained. The average results for 17 individuals have 

 been collected in table 55. As in the preceding table, the subjects have been 

 arranged in the order of the bod}Mveights. Since in experiments with muscular 

 work, the preceding muscular activity may have a possible influence upon the 

 body of the subject and there may be an accumulation of large amounts of 

 condensed water on the heat-absorbing system inside the chamber, we have 

 here selected only those experiments in which the sleep followed rest to compare 

 with experimental periods during the waking hours when the subject did no 

 muscular work and was at rest. 



Table 55. Water vaporized during sleep by different individuals, after rest 



(1 a. m. to 7 a. m.). 



1 The body-weights are practically those given for the same subjects in table 54, although there 



are certain variations, especially with the subjects N. M. P. and A. H. M. 3 



2 In computing body-surface the formula of Meeh has been used : 12.312 Vbody-weight. 



