CHAPTER IV 



THE CHEMISTRY OF FOOD 



The Source of Food Inorganic Substances Water Salt Lime 

 Iron Organic Substances Albumen, Fibrin, and Caseine The 

 Fats or Oils The Sugars, Starch, and Gum Stimulating Substances 

 Necessity of a Regulated Diet 



1. The Source of Food. The term food includes all those 

 substances, whether liquid or solid, which are necessary for 

 the nourishment of the body. The original source of all food 

 is the earth, which the poet has fitly styled the " Mother of all 

 living." In her bosom, and in the atmosphere about her, are 

 contained all the elements on which life depends. But man 

 is unable to obtain nourishment directly from such crude 

 chemical forms as he finds in the inorganic world. They 

 must, with a few exceptions, be prepared for his use, by being 

 transformed into new and higher combinations, more closely 

 resembling the tissues of his own body. 



2. This transformation is effected, first, by the vegetable 

 world. But all plants are not alike useful to man, while some 

 are absolutely hurtful. Accordingly, he must learn to discrimi- 

 nate between that which is poisonous and that which is life- 

 supporting. Again, all parts of the same plant or tree are not 

 alike beneficial : in some, the fruit ; in others, the leaves ; and 

 in others, the seeds only are sufficiently refined for his use. 

 These he must learn to select ; he must also learn the proper 

 modes of preparing each kind for his table, whether by cooking 

 or other processes. (Eead Note 1.) 



1. The Circle of Organic Life. "Man, as an animal, is chemically an 

 oxidizing agent, reducing again to primitive forms the principles built up 



1. The term food ? Source of food ? Need of preparing food ? 



2. Usefulness and hurtfulness of plants ? What then must man do ? Parts of the same 

 plant or tree ? 



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