FOOD 117 



with water by using a chemical base. Olive oil can be 

 made to mix with water if a small quantity of ammonia 

 or potassium hydroxide is added. When oils are mixed 

 with water by the aid of a base the mixture is known as 

 an emulsion. The most perfect emulsion, in which no 

 base is used, is milk. Hot soups have more or less fat 

 mixed with the water and are very poor emulsions. 



Fats, like carbohydrates, are composed of hydrogen, 

 carbon, and oxygen, but they do not have very much oxy- 

 gen, and therefore a great quantity of oxygen is required 

 to oxidize them. Since much ^> o^^ /~\oc> 

 oxygen is used in the oxida- OQ * ^MP 

 tion of fats, they produce >gofQ o 0*0 

 about two and one-fourth times oo 00 J OoO 

 as much heat as carbohy- dO O oo 

 drates. The products coming ^b**9? * O 

 from the oxidation of fats are ooOo?} 

 water and carbon dioxide. o oQ> <. 



Fats are digested in the ? * Qo o 



small intestines by the diges- o o 



tive fluid, which makes an FAT GLOBULES IN MILK 

 emulsion out of the fat. This 



emulsion can pass through the walls of the intestine and 

 get into the blood by way of the thoracic duct. (Ask 

 the teacher to tell you more about it.) Soaps are also 

 made in the intestine from fat for cleansing purposes. 

 When soaps are made glycerine is also formed. The 

 body uses the fat for making heat, which is done by 

 oxidation. Fat is also stored up in various parts of the 

 body for protection against cold and against possible 

 injuries. The stored fat is also used at times when not 

 enough food can be procured, or during sickness, for 

 keeping the body temperature normal. 



