592 THE POPULAR SCIJEXCE MONTHLY. 



cal and mental development by the food they take, than the individu- 

 als of whom that sum is made up ? This seems to be the decision of 

 history. Philosophers (even the great thinker of Konigsberg himself) 

 have not a word to say about the influence on human races and peo- 

 ples of difierent food-supplies. The world heard at first with aston- 

 ishment the saying of a famous scientific man, that, " could man live on 

 air and water alone, such notions as master and servant, prince and 

 subject, friend and foe, hate and love, virtue and vice, right and 

 wrong, etc., would have no existence, and political communities, social 

 and family life, human intercourse, commerce, trade, and industry, 

 art and science — in a word, whatever makes man what he is — depend 

 entirely on the fact that man possesses a stomach and is subject to a 

 law of Nature which compels him daily to take a certain amount of 

 food." 



As we start out with the principle, too late recognized in historical 

 research, that the selection of articles of food is not only important 

 for the personal well-being of the individual, but that it is a weighty, 

 world-stirring question for countries and nations in its bearings on the 

 history of civilization, we will, therefore, endeavor to look closely 

 into it, and study the mode in which this influence is exerted. 



If nations are to flourish, they, no less than individuals, need 

 wholesome, strong food. The only question is. How are we to deter- 

 mine what food is strong and w^holesome ? Foods have been classed 

 in diflerent groups, according to the influence they have on the body, 

 in virtue of their essential constituents ; and though this classification, 

 like every artificial classification we make in Xature, is only approxi- 

 mately correct, still it gives us some ground to stand on. Blood- 

 formers, or albuminates, are those albuminous materials which consti- 

 tute the nutritive elements of the blood, and enter into the composi- 

 tion of the muscles, bones, sinews, and ligaments, on which the exer- 

 cise of force specially depends. The heat-producers or respiratory 

 foods are those rich in carbon ; these specially serve to support, with 

 the aid of inspired oxygen, the process of combustion so necessary 

 for the purposes of the organism. Finally, there is a third group of 

 nutritious substances — the nutritive salts — which are of an inorganic 

 nature, and which, after combustion of the food, remain in the shape 

 of ash. 



All these food-materials are essential, since with them the organ- 

 ism is built up. Life is an unceasing process of waste and repair, 

 and the food must make good the loss the organism sufiers every 

 instant. Even those substances which are contained in the living 

 body only in small quantities must be supplied, for on this depends 

 the activity of important organs. Such substances are common salt, 

 potash, lime, magnesia, phosphoric acid, and, above all, iron, with- 

 out which the blood-corpuscles would lose their vitality. But none 

 of these groups is, by itself, suflicient for nutrition ; they must all be 



