Metabolism Experiment No. 68. 65 



Balance of water. The outgo of water may be considered as of two kinds, 

 preformed water and water resulting from the oxidation of organic hydrogen. 

 Making due allowance for the drinking-water, the quantities of preformed 

 water actually lost from the body tissues and fluids are given in column / 

 of table 28. The water resulting from the oxidation of the organic hydrogen 

 in the protein, fats, and carbohydrates katabolized, is given in column g 

 of the same table. 



Changes in Body-Weight Compared with Balance of Income and Outgo. 



Knowing the factors of the income and the outgo, it should be possible to 

 compute accurately the changes in body-weight, and conversely an accurate 

 measure of the changes of body-weight should serve as a check upon the 

 accuracy of the determinations involved in striking a balance between income 

 and outgo. As a result of much preliminary experimenting, an apparatus was 

 devised by which the subject could be seated in a suspended chair inside the 

 chamber and his weight be recorded on a scale beam outside the calorimeter 

 chamber. This apparatus, which is described in detail elsewhere, 17 has proved 

 more accurate than the ordinary platform scale formerly in use. This weigh- 

 ing apparatus was first put to practical use in the series of experiments which 

 immediately preceded metabolism experiment No. 68. 



In the series of experiments here reported, the subjects were weighed each 

 morning at a few minutes after 7 a. m., though the time of weighing and the 

 time consumed in the process was not the same from day to day. While all 

 the subjects urinated after 7 a. m. each morning, some of the subjects urinated 

 before weighing, and hence it seemed desirable to refer all body-weights 

 to exactly 7 a. m., not only to make them more nearly comparable but because 

 the body-weights at exactly this hour are necessary in making the correction 

 for gain or loss of energy due to changes in body-weight. In order, therefore, 

 to refer these weights to 7 a. m. it became necessary to add to the body-weight, 

 as found by the platform scale, the weight of the urine passed after 7 a. m. in 

 case the subject urinated before he was weighed. In cases where the subject 

 was weighed immediately after 7 a. m. and before urinating, the weight as 

 found on the platform scale was taken as the weight at 7 a. m. In experiment 

 No. 68 the subject urinated before weighing. 



In table 29 and corresponding tables in subsequent experiments, it will be 

 found that there are slight discrepancies between the gain or loss of body 

 material as estimated and the gain or loss of body-weight as found by the scale. 

 These discrepancies are probably due to a large number of difficulties which 

 arose from the fact that the subjects were not weighed each morning with 

 exactly the same articles of clothing, etc., on their persons. It also happened 



17 Carnegie Institution of Washington Publication No. 42, p. 158. 

 5 



