CHAPTER XIII 

 FATS, WAXES, AND LIPOIDS 



Where it is a duty to worship the sun, it is pretty sure to be 

 a crime to examine the laws of heat. 



— Voltaire. 



As mentioned in Chapter III, there are other ternary foods 

 (foods composed of three elements) besides the carbohydrates, 

 viz., the fatty substances. Although they contain the same ele- 

 ments as the carbohydrates, they have relatively less oxygen and 

 more hydrogen. The fatty foods are commonly divided into fats 

 and oils, but there is no chemical difference between a fat and an 

 oil. The term "oil" is simply used to designate those fats which 

 are liquid at ordinary temperatures and thus it denotes a physical 

 state rather than a chemical combination. The mineral oils such 

 as kerosene, gasoline, etc., are not related and belong to an entirely 

 different category of substances. 



Economic Uses of Fats. — Fats are common in storage organs 

 throughout the plant kingdom, especially in seeds. The follow- 

 ing table of plants with the percentage of contained fats will give 

 an idea of the wide range of families where fats are found in large 

 quantities. 



Almonds 42% Corn 4% Peach pits 35% 



Brazil nuts 68% Cottonseed 24% Poppy seed 47% 



Castor beans 5.1 % Flaxseed 30% Pumpkin seed 41% 



Cocoa 54% Hazel nuts 55% Rapeseed 42% 



Coconut 65% Hempseed 33% Sunflower seed 38% 



Coffee 12% Mustard seed 25% Walnuts 52%. 



Olives 50% 



Among these are many fats and oils of commercial importance, 

 which are used for food, lighting, lubricating, manufacture of 

 soaps, and many other purposes. 



Castor oil is used in the dye industry after conversion into 

 "turkey red" oil. It is also used in medicine as an internal lu- 

 bricant and since the development of aviation has been much in 

 demand as a lubricant for air motors. 



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