FOODS AND DIET. 209 



To this should be added 296. grammes water, which are produced by 

 the union of hydrogen and oxygen in the body during the process of 

 oxidation (i. e., 32.89 hydrogen and 263.11 oxygen). There are twenty- 

 six grammes of salts got rid of by the urine and six by the fasces. 



The quantity of carbon daily lost from the body amounts to about 

 281.2 grammes or nearly 4,500 grains, and of nitrogen 18.8 grammes or 

 nearly 300 grains; and if a man could be fed by these elements, as such, 

 the problem would be a very simple one; a corresponding weight of 

 charcoal, and, allowing for the oxygen in it, of atmospheric air, would 

 be all that is necessary. But an animal can live only upon these ele- 

 ments when they are arranged in a particular manner with others, in the 

 form of an organic compound, as albumen, starch, and the like; and the 

 relative proportion of carbon to nitrogen in either of these compounds 

 alone, is, by no means, the proportion required in the diet of man. 

 Thus, in albumen, the proportion of carbon to nitrogen is only as 3.5 to 

 1. If, therefore, a man took into his body, as food, sufficient albumen 

 to supply him with the needful amount of carbon, he would receive more 

 than four times as much nitrogen as he wanted; and if he took only 

 sufficient to supply him with nitrogen, he would be starved for want of 

 carbon. It is plain, therefore, that he should take with the albuminous 

 part of his food, which contains so large a relative amount of nitrogen 

 in proportion to the carbon he needs, substances in which the nitrogen 

 exists in much smaller quantities relatively to the carbon. 



It is therefore evident that the diet must consist of several sub- 

 stances, not of one alone, and we must therefore turn to the available 

 food- stuffs. For the sake of convenience they may be classified as 

 under: 



A. ORGANIC. 



I. Nitrogenous, consisting of Proteids, e.g., albumen, casein, 



syntonin, gluten, legumin and their allies ; and Gelatins, 

 which include gelatin, elastin, and chondrin. All of these 

 contain carbon, hydrogen, oxygen, and nitrogen and some in 

 addition, P. and S. 



II. Non-Nitrogenous, comprising : 



(1.) Amyloid or saccharine bodies, chemically known as carbo-hy- 

 drates, since they contain carbon, hydrogen, and oxygen, with 

 the last two elements in the proportion to form water, i.e., 

 H^nOn. To this class belongs starch and sugar. 



(2.) Oils and fats. These contain carbon, hydrogen, and oxygen, 

 but the oxygen is less in amount than in the amyloids and 

 saccharine bodies. 



B. INORGANIC. 



I. Mineral and saline matter. 



II. Water. 



14 



