202 ELEMENTS OF PHYSIOLOGY 



with proteid, the required proportion of nitrogen to carbon 

 can be attained. In about two pounds of bread there is 

 enough carbon for the day's needs, but it gives only half 

 enough nitrogen. So, by combining lean meat, cheese, 

 beans, or nuts with bread, a sufficiency of both elements is 

 obtained without unnecessary work or waste. With the 

 addition of plenty of water and a little salt, the diet is 

 chemically complete. 



358. How Different Peoples attain the Proportion. Milk 

 has an excess of nitrogen, and oatmeal an excess of car- 

 bon ; oatmeal and milk form a perfect food, and it is not 

 surprising that a whole race (the Scotch) have lived upon 

 it and thrived. Potatoes are mostly starch and water ; the 

 starch in them is more than four times as much as the pro- 

 teid, and an Irishman who tried to live on potatoes alone, 

 would have to eat seven pounds a day to get enough proteid. 

 By eating milk and eggs also, he can get along on half the 

 amount of potatoes named above, and every Irish peasant 

 is said to keep a cow and chickens. The Mexicans eat 

 bread made of corn meal, and supply the proteid by using 

 beans as a constant article of diet. The Zulus live on 

 cracked corn by adding milk to it. The Arabs live on 

 barley and camels' milk, rarely eating the camels' flesh. 

 Hundreds of millions of people in Asia (the Hindoos, Chi- 

 nese, and others) subsist mainly on rice, which is more 

 nearly pure starch than any of the grains, containing only 

 6 per cent of proteid, about half as much as wheat and 

 corn ; the chief addition they make is butter or other fat, 

 and beans, which contain vegetable proteid. Their meagre 

 diet may partly account for their lack of energy and brav- 

 ery, and the ease with which they are conquered and con- 

 trolled by European nations. The greatness of a people is 

 largely dependent upon their diet. 



359. The Body's Method of regulating the Food. We 

 should not think that the food eaten must be regulated 



