156 ALIMENTATION 



that the supply of food has a great influence on the quantity of the 

 excretions. An illustration of this is the influence of food on the ex- 

 halation of carbon dioxide ; and this is but an example of what takes 

 place in regard to other excretions. The quantity of the excretions is 

 even more strikingly modified by exercise, which, within physiological 

 limits, increases the vigor of the system, provided the increased quantity 

 of food required be supplied. 



The Daily Ration. The daily loss of substance which must be 

 supplied by matters introduced from without is considerable. A large 

 portion of this discharge takes place by the lungs, and a consideration 

 of the mode of introduction of gases to supply part of this waste belongs 

 to the subject of respiration. The most abundant discharge which is 

 compensated by absorption from the alimentary canal is that of water 

 both in a liquid and vaporous condition. The entire quantity of water 

 eliminated daily has been estimated at about four and a half pounds 

 (2041 grams), and it is probable that about the same quantity is intro- 

 duced in the form of drink and as a constituent of the so-called solid 

 articles of food. The quantity taken in the form of drink varies with 

 the character of the food. When the solid articles contain a large 

 proportion of water, the quantity of drink may be diminished ; and it 

 is possible, by taking a large quantity of the watery vegetables, to exist 

 entirely without drink. There is no article more frequently taken than 

 water, merely as a matter of habit, any excess being readily removed 

 by the kidneys, skin and lungs. Dalton estimates the daily quantity 

 necessary for a full-grown healthy male, at fifty-four fluidounces (1530 

 grams), or 3.38 pounds. 



The quantity of solid food necessary to nutrition is shown by esti- 

 mating the solid matter in the excretions ; and the facts thus ascer- 

 tained correspond closely with the quantity of material which the 

 system has been found to actually demand. The following are the 

 estimated daily losses of the organism : 



Carbon (or its I Respiration, 8.825 ounces (250 grams)/ IQ ounces 



equivalent). (Excretions, 2.116 ounces (' 60 grams) \ 

 Nitrogenous substances (containing 308.64 grains, or 



20 grams of nitrogen) ... . . . 4.586 ounces (130 grams). 



15.527 ounces (440 grams). 



From this it is estimated that the normal ration, supposing the food 

 to consist of lean meat and bread, is as follows : 



Bread . . . . -. . . ... . 35.300 ounces (1000 grams). 



Meat (without bones) . .- -,. .-... .- > . . 10.088 ounces (286 grams). 



45.388 ounces (1286 grams). 



