394 



GENERAL SCIENCE 



Add a few drops of vinegar to a solution of cane sugar 

 and then test with Fehling's solution. 



Add a drop of hydrochloric acid to a few cubic centi- 

 meters of cane sugar solution and boil. When cool, add 

 enough sodium carbonate solution to neutralize, and test 

 with Fehling's solution. What change has the hydro- 

 chloric acid produced? 



Fats. - - These include ordinary meat fats and all 

 vegetable and animal oils. Fats contain the same ele- 

 ments as the carbohydrates, but in different proportions. 

 The principal kinds of fats used as food are the fats of 



meats, butter, olive 

 oil,"palmoil, cotton- 

 seed oil, and al- 

 mond oil (Figure 

 352). They are in- 

 soluble in water but 

 are readily soluble 

 in ether, chloro- 

 form, and gasoline. 



Fatty foods are high in heat value and form the prin- 

 cipal diet of the inhabitants of cold climates. When 

 more fat is digested than is required for the present uses of 

 the body, it is stored in various parts of the body as a 

 reserve which may be used when needed. 



The vegetable fats of commerce are in liquid form, 

 while the animal fats are usually solids. This, however, 

 is not true of the animal fats in their original state, where 

 they too are liquids. Fat in animals occurs as minute 

 drops inclosed in tiny sacs. When fresh milk is allowed 

 to stand, the millions of little fat drops rise to the surface 

 of the milk, as cream. 



Vitamines. In addition to the well-known classes of 



