108 ELEMENTARY BIOLOGY 



to comparatively simple nitrogenous compounds, we shall see that it 

 is absurd to claim a specific value for one kind of food in connection 

 with the building of special tissues. All the products of protein, fat, 

 and carbohydrate digestion are distributed without discrimination by 

 the blood, and from this general store all the cells absorb their supplies. 



140. Minerals in the food. So far nothing has been said 

 about the selection of food with respect to the mineral con- 

 tents. The reason for this is that our ordinary food materials 

 contain an abundance of salts in their natural condition, and 

 it is comparatively rare to see a person who suffers for lack 

 of minerals in the diet. Before the outbreak of the European 

 war there was a real danger that the refinements of food 

 through improved methods of manufacture would result in 

 a real scarcity of minerals in our foods. This is illustrated 

 by the fact that bread made from graham (whole-wheat) flour 

 contains from three to five times as much mineral matter 

 as that made from patent white flour, in which only the 

 interior portions of the wheat grain are present. Not only the 

 lime but much of the phosphorus and other mineral substances 

 .are lost to us by the overrefinement of food preparation. 1 



The growing bones of a child or any other young mammal 

 can be built up only if there is an abundance of lime in the 

 food. Growing children, therefore, should have more lime than 

 adults, just as growing chicks need to be supplied with broken 

 oyster shells or some other form of material containing lime, 

 and just as laying hens need more lime than roosters, since 

 lime is used in the formation of eggshells. Indeed, many 

 farmers and poultry raisers save eggshells to feed back to 

 their poultry. 



1 Children that suffer from lack of minerals in their food often develop the 

 diseased condition of the bones known as rickets. A curious disease known 

 in the East as beriberi, which involves an inflammation of the nerve cover- 

 ings, seems to be caused by a diet consisting chiefly of polished rice ; that is, 

 rice from which the outer coat has been removed. It is believed that the 

 absence of the salts of the rice (and possibly of certain organic compounds 

 from the outer coating) is the cause of the disease. 



