XIX. FOODS AND DIETARIES 



Problems. A study of foods to determine : 

 (a} Their nutritive value. 



(b) The relation of work, environment, age, sex, and diges- 

 tibility of foods to diet. 



(c) Their relative cheapness. 



(d} The daily Calorie requirement. 



O) Food adulteration. 



(/) The relation of alcohol to the human system. 



LABORATORY SUGGESTIONS 



Laboratory exercise. Composition of common foods. The series of 

 food charts supplied by the United States Department of Agriculture 

 makes an excellent basis for a laboratory exercise to determine common 

 foods rich in (a) water, (6) starch, (c) sugar, (d) fats or oils, (e) protein, 

 (/) salts, (g) refuse. 



Demonstration. - - Method of using bomb calorimeter. 



Laboratory and home exercise. - To determine the best individual bal- 

 anced dietary (using standard of Atwater, Chittenden, or Voit) as deter- 

 mined by the use of the 100-Calorie portion. 



Demonstration. - - Tests for some common adulterants. 



Demonstration. - - Effect of alcohol on protein, e.g. white of egg. 



Demonstration. - - Alcohol in some patent medicines. 



Demonstration. - - Patent medicines containing acetanilid. Determina- 

 tion of acetanilid. 



Why we Need Food. - - A locomotive engine takes coal, water, 

 oxygen, from its environment. A living plant or animal takes 

 organic food, water, and oxygen from its environment. Both the 

 living and nonliving machine does the same thing with this fuel 

 or food. They oxidize it and release the energy in it. But the 

 living organism in addition may use the food to repair parts that 

 have broken down or even build new parts. Thus food may be 

 defined as something that releases energy or that form,s material for 



272 



