64 HAND-BOOK OF PHYSIOLOGY. 



Altogether, the Expenditure of the body represented by the sum of 

 these various excretory products amounts every 24 hours to 



Solid and gaseous matter . . . 17,150 grains (1,113 grms.) 

 Water (either fluid or combined with 

 the solids and gaseous matter). . 49,500 (2,695 " ) 



The matter thus lost by the body is matter the chemical attractions of 

 which have been in great part satisfied; and which remains quite useless 

 as food, until its elements have been again separated and re-arranged by 

 members of the vegetable world (p. 2, Vol. L). It is especially instructive 

 to compare the chemical constitution of the products of expenditure, thus 

 separated by the various excretory organs, with that of the sources of in- 

 come to be immediately considered. 



It is evident from these facts that if the human body is to maintain 

 its size and composition, there must be added to it matter corresponding 

 in amount with that which is lost. The income must equal the expen- 

 diture, 



2. Sources and Amount of Income. The Income of the body 

 consists partly of Food and Drink, and partly of Oxygen. 



Into the stomach there is received daily: 



Solid (chemically dry) food . . 8, 000 grains (520 grms.) 



Water (as water, or variously com- 

 bined with, solid food) . . . 35,000-40,000 " (2,444 " ) 



By the lungs there is absorbed daily: 

 Oxygen 13,000 " 844 " ) 



The average total daily receipts, in the shape of food, drink and oxy- 

 gen, correspond, therefore, with the average total daily expenditure, as 

 shown by the following table: 



20,000 grains. 

 11,750 " 

 24,100 " 

 2,800 " 



58,650 grains 



These quantities are approximate only. But they may be taken as 

 fair averages for a healthy adult. The absolute identity of the two 



