326 THE HUMAN BODY. 



amount of nitrogen must be taken. Of dry proteids 52? 

 grams (8116 grains) would yield the necessary carbon, but 

 would contain 79 grams (1217 grains) of nitrogen; or four 

 times more than is required to cover the necessary daily 

 losses of that element. Fed on a purely proteid diet a man 

 would, therefore, have to digest a vast quantity to get enough 

 carbon, and in eating and absorbing it, as well as in getting 

 rid of the extra nitrogen which is useless to him, a great deal 

 of unnecessary labo,r would be thrown upon the various or- 

 gans of his Body. Similarly, if a man were to live on bread 

 alone he would burden his organs with much useless work. 

 For bread contains but little nitrogen in proportion to its 

 carbon, and so, to get enough of the former, far more carbo- 

 naceous substances than could be utilized would have to be 

 eaten, digested and eliminated daily. 



Accordingly, we find that mankind in general employ a 

 mixed diet when they can get it, using richly proteid sub- 

 stances to supply the nitrogen needed, but deriving the car- 

 bon mainly from non-nitrogenous foods of the fatty or carbo- 

 hydrate groups, and so avoiding excess of either. For instance, 

 lean beef contains about \ of its weight of dry proteid, which 

 contains 15 per cent of nitrogen. Consequently the 133 

 grams (2048 grains) of proteid which would be found in 532 

 grams (1 Ib. 3 oz.) of lean meat would supply all the nitrogen 

 needed to compensate for a day's losses. But the proteid 

 contains 52 per cent of carbon, so the amount of it in the 

 above weight of fatless meat would be 69 grams (1062 grains) 

 of carbon, leaving 205 grams (3157 grains) to be got either 

 from fats or carbohydrates. The necessary amount would be 

 contained in about 256 grams (3942 grains) of ordinary fats 

 or 460 grams (7084 grains) of starch; hence either of these, 

 with the above quantity of lean meat, would form a far better 

 diet, both for the purse and the system, than the meat alone. 



As already pointed out, nearly all common foods contain 

 several foodstuffs. Good butcher's meat, for example, con- 

 tains nearly half its dry weight of fat; and bread, besides 

 proteids, contains starch, fats and sugar. In none of them, 

 however, are the foodstuffs mixed in the physiologically best 

 proportions, and the practice of employing several of them at 

 each meal, or different ones at different meals, during the day, 

 is thus not only agreeable to the palate but in a high degree 

 advantageous to the Body. The strict vegetarians who do 



