X 



22 HUMAN PHYSIOLOGY. 



The amount of food required in 24 hours is estimated from the total 

 quantity of carbon and nitrogen excreted from the body in 24 hours ; these 

 two elements representing the waste or destruction of the carbonaceous 

 and nitrogenized compounds. It has been determined by experimentation 

 that about 4600 grains of carbon and about 300 grains of nitrogen are 

 eliminated from the body daily; the ratio being about 15 to I. That the 

 body may be kept in its normal condition, a proper proportion of carbon- 

 aceous (bread) to nitrogenized (meat) food should be observed in the 

 diet. 



The method of determining the proper amounts of both kinds of food is 

 as follows : 



1000 grains of bread (2 oz.) contain 300 grs. C. and 10 grs. N. 



To obtain the requisite amount of nitrogen from bread, 30,000 grains, 

 or about 4 Ibs., containing 9000 grains of carbon and 300 of nitrogen, 

 would have to be consumed. Under such a diet there would be a large 

 excess of carbon, which would be undesirable. On a meat diet the reverse 

 obtains : 



looo grains of meat (2 oz.) contain 100 grs. C. and 30 grs. N. 



To obtain the requisite amounts of carbon from meat, 45,000 grains, or 

 about 6^ Ibs. , containing 4500 grains of carbon and 1350 grains of nitro- 

 gen, would have to be consumed. Under such circumstances there would 

 arise an excess of nitrogen in the system, which would be equally undesir- 

 able and injurious. By combining these two articles, however, in proper 

 proportion, the requisite amounts of carbon and nitrogen can be obtained 

 without any excess of either, e. g. : 

 * 



2 Ibs. of bread contain 4630 grs. C. and 154 grs. N. 

 ^f " meat " 463 " " " 154 " " 



5093 C. 308 N. 



The amount of carbon and nitrogen necessary to compensate for the loss 

 to the system daily would be contained in the above amounts of food. As 

 about 3^ oz. of oil or butter are consumed daily, the quantity of bread 

 can be reduced to 19 oz. In the quantities of bread and meat above men- 

 tioned, there are 4.2 oz. albumen, 9.3 oz. sugar and starch. 



