28 LABORATORY EXERCISES. 



2 1 Test it with nitric acid and ammonia. What 

 kind of nutrient is gluten? 



B. Carbohydrates. 



1. Test with iodine a small amount of the 



sediment in the water which you used at 

 the beginning of the experiment. What 

 part of the flour was washed through 

 the cloth? 



2. Test with nitric acid and ammonia another 



portion. Are nitrogenous substances 

 present? 



3. Test a small portion of the sticky mass in 



the cloth with iodine. What is the re- 

 sult, and what is your conclusion ? 



4. Place a little flour in a test-tube, add water 



and boil ; add Fehling's solution and boil 

 again. Is grape-sugar present in flour? 



C. Mineral matter. 



Place a small amount of dry flour on a piece 

 of tin or platinum foil and cause it to burn 

 over a very hot flame. 



1. What changes take place? 



2. What is left after the burning? 



D. Summary. 



1. What nutrients are present in flour? 



2. State how each of these nutrients can be 



separated from the rest. 



