Water Vaporized from Lungs and Skin. 147 



grams. The water vaporized and leaving the chamber in the air-current, 

 making due allowance for the variations in the water-vapor residual in the air 

 of the chamber, showed that during the period of waking hours this subject 

 gave off 436 grams of water. From the above calculation it is seen that 194.8 

 grams has been computed as having been exhaled from the lungs and conse- 

 quently the difference, 241.2 grams, is computed as having been vaporized from 

 the skin. Of the total amount exhaled, therefore, 44.7 per cent was vaporized 

 from the lungs and 55.3 per cent was vaporized from the skin. The other 

 experiments were calculated in the same way, and a summary of the results 

 is given in the table. 



An examination of table 56 shows that there are wide variations in the per- 

 centages of the water-vapor leaving the lungs and skin. The lowest percentage 

 of water-vapor leaving the lungs is 21 with Miss S. The other woman subject, 

 Miss B., also shows a low percentage. The highest result is that with the sub- 

 ject H. R. D., since 51.4 per cent of the total water vaporized was computed 

 as being vaporized from the lungs. Leaving out of discussion the 2 experiments 

 with women, the lowest percentage of water-vapor leaving the lungs in experi- 

 ments with men is that found for H. A. P., i. e., 26.2 per cent. The average 

 of the results with 53 subjects at rest shows that 36.3 per cent of the total 

 water vaporized leaves the body as aqueous-vapor in the expired air. 



While the data regarding women are admittedly too meager for generaliza- 

 tion, the results are suggestive of numerous lines of research as to the relations 

 of the vaporization of water from the lungs and skin as affected by the dress 

 of women, the possible influence of wearing corsets on the ventilation of the 

 lungs, and the influence of the larger preponderance of subcutaneous fat * upon 

 the water vaporized from the skin. 



Apportionment to Lungs and Skin during Sleep. 



On the general principle that during sleep all metabolic functions are more 

 nearly on a level, there is less muscular activity, and the general conditions of 

 the experiment are much more satisfactory for comparison, the experiments 

 during the night period (la. m. to 7 a. m.) have been collected with the view 

 of studying the proportions of water vaporized from the lungs and skin under 

 conditions of the unusual quiet obtaining during sleeping hours. The method 

 of computation is exactly that outlined on page 146. The results are recorded 

 in table 57 herewith. 



The striking feature of the results obtained during the sleeping hours is 

 that the proportion of water computed as vaporized from the lungs is essen- 

 tially that found during the waking hours, and apparently it is immaterial 

 whether the subject is sitting up awake or lying quietly asleep as to the relative 

 amounts of water vaporized from the lungs and skin, provided that the subject 



1 Schattenfroh, Archiv f. Hygiene, 1900, 38, p. 108. 



