CONCLUSION. 193 



energy of this stored material was obtained from that of the food in 

 excess of that required to supply the needs of the body, the figures of 

 column (h*) are subtracted from those of column (d} to make the total 

 energy of material oxidized. 



The output of energy consists of the heat given off from the body 

 either as sensible heat or heat of vaporization of water. Both quanti- 

 ties are measured directly by the respiration calorimeter. The figures 

 in column (/) show the amounts of heat thus measured. These are 

 taken from column (g} in Table n. Theoretically, the quantity for 

 intake should be the same as that of the output. It would hardly be 

 expected, however, that results agreeing exactly would be obtained. 

 Column () shows the difference between the heat measured by the 

 respiration calorimeter and the energy of material oxidized in the body 

 as estimated from the heat of combustion of food, feces and urine, and 

 that of body material gained or lost. This difference is expressed in 

 column (/) in percentages of the amounts in (/) . 



CONCLUSION. 



Throughout this report the attempt has been made to indicate the 

 experimental limitations as well as the relative accuracy of this appa- 

 ratus. Believing that improvement in experimental technique is an 

 essential in increasing our knowledge of those processes of physiolog- 

 ical chemistry that have special reference to the nutrition of man, we 

 have aimed in the development of this apparatus to secure in so far as 

 possible the accuracy of those forms of physical apparatus ordinarily 

 designated as instruments of precision. The incidental errors of 

 manipulation and computation are by no means wholly eliminated. 

 Indeed, as is to be expected with an apparatus involving so many 

 mechanical details, the number of possible errors is not inconsiderable. 

 We believe, however, that in fundamental principles and practical use 

 it has proved as exact as could well be expected of an apparatus for 

 physiological experimenting. 



