DAILY QUANTITY OF FOOD REQUIRED. 



359 



voir of potential energy, from which the kinetic energy (in its various forms) and 

 the heat of the body are obtained, the absolute amount of food must be increased 

 when the body loses more heat, as in winter, and when more muscular activity 

 (work) is accomplished. As a general rule an adult requires daily 130 grammes 

 proteids, 84 grammes fats, 404 grammes carbohydrates, and 30 grammes salts. 



A Healthy Adult requires in 24 Hours of water-free solids . 



[When we record these numbers in ounces we get the following results as water- 

 free solids required by an average man (Parkes) : 



During ordinary work the proportion is about : 



Proteids 1 : fats 0'6 : carbohydrates 3*0, 

 i.e., 1 nitrogenous to 3*6 non-nitrogenous.] 



[In a diet for ordinary work (23 oz. of dry solids) a man takes about y^- part 

 of his own weight daily ; ordinary food, however, as it is consumed, contains be- 

 tween 50 and 60 per cent, of water ; if we add this proportion of water to the 

 actually dry food, we get 48 to 60 oz. of ordinary food (exclusive of liquids). But 

 we consume 50 to oz. of water in some liquid form, making the total amount of 

 water 70 to 90 oz. (Parkes).'] 



The following tables show the elementary composition of the income and ex- 

 penditure : 



An Adult doing a Moderate Amount of Work takes in : 



Add 744*11 grm. O from the air by respiration. 

 2818 H 2 0. 



,, 32 ,, Inorganic compounds (salts). 



The whole is equal to 3J kilos. [7 lbs.], i.e., about -fa of the body-weight ; so 

 that about 6 per cent, of the water, about 6 per cent, of the fat, about 1 per cent, 

 albumin, and about 0*4 per cent, of the salts of the body are daily transformed 

 within the organism. 



