368 



THE CENTURY BOOK OF FACTS. 



well as sulphuric, hydrochloric, phosphoric, 

 and fluoric acids and water ; also, nearly all 

 the fat which it consumes daily, and probably 

 all the nitrogenous substances which it re- 

 quires and which are closely allied in compo- 

 sition, as albumen, fibrin, etc. "So great an 

 array of mysterious substances," says Dr. 

 Smith, " might well prevent us from feeding 

 ourselves or others if the selection of food de- 

 pended solely upon our knowledge or judg- 

 ment ; but it is not so, for, independently of 

 the aid derived from our appetites, there is the 

 great advantage of having foods which con- 

 tain a proportion of nearly all these elements ; 

 and combinations of foods have been effected 

 by experience which protect even the most 

 ignorant from evil consequences. Thus flesh, 

 or the muscular tissue of animals, contains 

 precisely the elements which are required in 

 our flesh-formers, and, only limited by quan- 

 tity, our heat-generators also ; and life may be 

 maintained for very lengthy periods upon ani- 

 mal food and water. Seeing, moreover, that 

 the source of flesh in animals which are used 

 as food, is of vegetable origin, it follows that 

 vegetables should contain the same elements 

 as flesh, and it is a fact of great interest that 

 in vegetables we have food elements closely 

 analogous to those contained in the flesh of 

 animals. Thus, in addition to water and salts, 

 common to both, there is vegetable chondrin, 

 vegetable albumen, vegetable fibrin, and vege- 

 table casein, all having a composition almost 

 identical with animal albumen, fibrin, chondrin 

 and casein." The articles containing most 

 of the three articles needed generally in the 

 body are as follows : for fat and heat-making 

 butter, lard, sugar and molasses; for flesh 

 or muscle-forming lean meat, cheese, peas, 

 beans, and lean fishes ; for brain and nerves 

 shell fish, lean meats, pease, beans, and very 

 active birds and fishes, who live chiefly on food 

 in which phosphorus abounds. In a meat 

 diet, the fat supplies the carbon for keeping 

 up the heat of the body, and the lean furnishes 

 nutriment for the muscles, brain, and nerves. 

 Green vegetables, fruits, and berries furnish 

 additional supplies of the acids, the salts, and 

 water needed. 



Kinds of Food. The simplest and most 

 powerful agent in determining the character of 

 our food is climate. In cold countries the 

 requirements of man are very different from 

 those felt in the tropics, and from the Esqui- 

 maux, who, according to Dr. Kane, will drink 

 ten or twelve gallons of train oil in a day, to 

 the Peruvians and other tropical nations for 

 whom the banana suffices for nearly all seasons 

 of the year, there are various gradations in 

 which the constituents of the diet bear a very 



direct relation to the prevailing temperature. 

 In cold regions man requires such food as not 

 only supplies him with nutriment, but also 

 with heat; as oil, butter, fat, sugar, and other 

 substances in which carbonaceous elements 

 predominate. In warm countries, on the con- 

 trary, it is one of the most essential conditions 

 of good health, that his food should be as lit- 

 tle heating as possible. Tn our own climate 

 this law holds good as between summer and 

 winter; in the latter season, plenty of lean 

 meat, butter, potatoes, eggs, sugar, and 

 similar food are necessary to keep the animal 

 machine in working order, while in summer 

 the diet should consist chiefly of those sub- 

 stances of which nitrogenous or flesh-forming 

 elements compose the largest part. There is 

 probably no other cause so fruitful in produc- 

 ing the dyspepsia and similar diseases of which 

 Americans, as a nation, are in a peculiar degree 

 the victims as the neglect to harmonize the 

 food with the changing seasons. 



The next most important question in deter- 

 mining the character of our food is that of its 

 digestibility ; and it must be borne in mind 

 that the nutritive value and the digestibility 

 of food have no necessary relation to each 

 other. A food may have a very high nutri- 

 tive value and yet be so indigestible as to be 

 practically useless, and on the other hand it 

 may be very easily digested and worth little or 

 nothing for nutrition. No general rules as to 

 the digestibility of different foods can be laid 

 down, because it depends very largely upon in- 

 dividual habits and conditions. Persons who 

 have a strong constitution, and take sufficient 

 exercise, may eat almost anything with appar- 

 ent impunity ; but young children who are 

 forming their constitutions, and persons who 

 are delicate, and who take but little exercise, 

 are very dependent for health upon a proper 

 selection of food. As a general thing, when 

 the body requires a given kind of diet, spe- 

 cially demanded by brain, lungs, or muscles, the 

 appetite will crave that food until the neces- 

 sary amount is secured. If the food in which 

 the needed aliment abounds be not supplied, 

 other food will be taken in larger quantities 

 than needed until that amount is gained ; for 

 all kinds of food have supplies for every part 

 of the body, though in different proportions. 

 Thus, for example, if the muscles are worked 

 a great deal, food in which nitrogen abounds 

 is required, and the appetite will remain un- 

 appeased until the requisite amount of nitro- 

 gen is secured. Should food be taken which 

 has not the requisite quantity, the consequence 

 will be that the vital powers will be needlessly 

 taxed to throw off the excess. There are other 

 kinds of food which are not only nourishing 



