THE CHEMISTRY OF FOOD 85 



eaten uncooked, for the grains of raw starch are but slightly 

 acted upon within the body. But, under the potent chemistry 

 of the sun's ray, this crude material is converted into sugar. 

 Thus are the fruits prepared by the careful hand of Nature, so 

 so that when ripe they may be freely used without further 

 preparation. 



27. Gum is commonly found in those articles which also con- 

 tain starch, and has the same chemical composition as the 

 latter, but is much less nutritious. In the East, gum-arabic 

 and similar substances are largely employed as food. Persons 

 who travel by caravan across vast, sandy deserts, find such 

 substances well adapted to their wants, since they are not 

 perishable, and are easily packed and carried. 



28. Stimulating Substances. The three classes of food-prin- 

 ciples already considered the Albuminoids, the Fats, and the 

 Sugars comprise all the more important organic ingredients 

 of our food. There are, besides, a great variety of coloring 

 and flavoring matters, that stimulate or increase the appetite 

 for food by appealing to the eye and taste ; but they are not 

 nutritious, and are quickly separated from the truly useful 

 substances, and do not long remain in the body. Among these 

 may be classed spices, flavors of fruits, tea, coffee, and vege- 

 table acids. 



too much sugar, just as they will eat too little fat. The harm it does them 

 is first, it is very apt to spoil the teeth; second, it takes away the ap- 

 petite for other food. If you are always eating sweet cakes and sugar- 

 plums, you will not care for plain, nourishing diet. Now, what is best for 

 us all is, to have good appetites for wholesome food ; it will do more to 

 keep us in health all our lives than anything else ; and there is a great 

 deal in getting the right habit." Candies are frequently adulterated with 

 plaster-of-paris, chalk, and certain forms of earth, that are indigestible ; 

 but worse than that, the coloring matters and flavoring extracts that are 

 used in the bright-tinted and fruity-flavored confectionery are absolute 

 poisons in many instances, such as arsenic, copper, zinc, lead, prussic and 

 sulphuric acid." Berner^s Lessons on Health (i 



2T. Gum, where found ? Its composition ? 



28. The three classes of food-principles ? What besides ? What is said of them ? Name 



the articles not nutritious. 









