94 HUMAN PHYSIOLOGY. 



300 of nitrogen, would have to be consumed. On such a diet there 

 would be a large excess of carbon, which would be undesirable. On 

 a meat diet the reverse obtains : 



1,000 grs. of meat (2 oz.) contain 100 grs. C and 30 grs. N. 



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

 or about 6 l /2 pounds, containing 4,500 grains . of carbon and 1,350 

 grains of nitrogen would have to be consumed. Under such cir- 

 cumstances there would arise an excess of nitrogen in the system, 

 which would be equally undesirable 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 pounds of bread contain 4,630 grs. C and 154 grs. 

 V* " meat " 463 " 154 



5,093 C. 308 N. 



The amount of carbon and nitrogen necessary to compensate for 

 the loss to the system daily would be contained in the foregoing 

 amount of food. As about 3^ ounces of oil or butter are consumed 

 daily, the quantity of bread can be reduced to 19 ounces. In the 

 quantities of bread and meat just mentioned there are 4.2 ounces 

 albumin, 9.3 sugar and starch. 



The alimentary principles are not introduced into the body as such, 

 but are combined in proper proportions to form compound sub- 

 stances, termed foods, e. g., bread, milk, eggs, meat, etc., the 

 nutritive value of each depending upon the extent to which these 

 principles exist. 



The following tables show the average composition of various 

 articles of food : 



