NECESSARY FOODS 



427 



must have been dissolved from the food. If a substance remains, 

 place a drop of it on a piece of paper. Smell of it. Try to mix it 

 with water. Rub it between the fingers. Try any other fat or 

 oil test of which you can think. 



Experiment 142. In a place where there is a good draft so that 

 odors will not penetrate the room, burn in an iron spoon over a 

 Bunsen burner (1) small 

 pieces of meat, (2) a 

 little condensed milk or 

 milk powder, (3) part of 

 an egg, and (4) any other 

 food. Is there a residue 

 left after burning? If 

 so, this is mineral matter. 



In the preceding 

 experiments we have 

 dealt with the three 

 great groups of organic 

 compounds, carbohy- 

 drates (starches and 

 sugars), fats and oils, 

 and proteins (foods 

 containing nitrogen) . 

 The foods that con- 

 tain large percentages 

 of carbohydrates are 

 vegetables, fruits, and 

 most cereals. The fats 

 are most abundant in butter, cream, fat meats, nuts, choco- 

 late, and vegetable oils such as olive and cottonseed oils. 

 The common foods that are rich in proteins are lean meats, 

 eggs, beans, peas, and certain cereals, especially oatmeal. 

 Milk contains all three of these compounds in approximately 

 the proportions needed by the body. 



A DATE PALM 



