METABOLISM, NUTRITION, AND DIET. 445 



Manifestations of Force in the form either of Heat or Motion. \n the 

 former case (Heat), the combustion must be sufficient to maintain a tem- 

 perature of about 37.8 0. (100 F.) throughout the whole substance of 

 the body, in all varieties of external temperature, notwithstanding the 

 large amount continually lost in the ways previously enumerated. In 

 the case of Motion, there is the expenditure involved in the (a) Ordi- 

 nary muscular movements, as in Prehension, Mastication, Locomotion, 

 and numberless other ways: as well as in (b) Various involuntary move- 

 ments, as in Respiration, Circulation, Digestion, etc. 



Manifestation of Nerve-force; as in the general regulation of all 

 physiological processes, e.g., Respiration, Circulation, Digestion; and 

 in Volition and all other manifestations of cerebral activity. 



The energy expended in all physiological processes, e.g. , Nutrition, 

 Secretion, Growth, and the like. 



The total expenditure or total manifestation of energy by an animal 

 body can be measured, with fair accuracy. All statements, however, 

 must be considered for the present approximate only, and especially is 

 this the case with respect to the comparative share of expenditure to 

 be assigned to the various objects just enumerated. 



The amount of energy daily manifested by the adult human body 

 in (a) the maintenance of its temperature ; (b) in internal mechani- 

 cal work, as in the movements of the respiratory muscles, the heart, 

 etc. ; and (c) in external mechanical work, as in locomotion, and all 

 other voluntary movements, is made up, according to McKendrick, as 

 follows : 



Metre- Gramme- 



kilogrammes, calories. 



Work of heart per diem . -. . . 88,000 

 Work of respiratory muscle . . 14,000 



Eight hours' active work / '.' 213,344 



315, 334 or 743,000 

 Amount of heat produced in 24 hours 1, 582, 700 or 3, 724, 000 



1,898, 034 or 4,467,000 



So that 4, 467 kilogramme calories represent the total energy manifested in 

 24 hours, 8 of which were employed in mechanical work, one-sixth of the 

 total energy being work. This estimation considerably exceeds those of others, 

 and the most general view is that the total energy exhibited in 24 hours by 

 the average adult is rather under than over 1, 000, 000 kilog. metres. 



Taking the diet-scale as given above (modified from Moleschott) , we may 

 see how this supplies the energy which is given out, remembering that 1 grm. 

 proteid = 5,000 to 5,500 calories; minus the value of grm. urea = 700 or 800 

 calories, = say 4,500; Igrm. fat = 9,000 calories; and 1 grm. carbohydrate = 

 4, 000 calories. 



