132 GENERAL SCIENCE 



are that the muscle fibers may be loosened and softened, 

 and that the bacteria and other parasites in the meat 

 may be killed by the heat. The common method of 

 frying makes foods less digestible. Stewing is an eco- 

 nomical as well as a healthful method. Slow boiling and 

 roasting are excellent methods of cooking meat. The 

 oven should be heated to a high temperature before the 

 roast is put into it. The heat will cause a crust to form 

 on the outer surface. This crust prevents the escape of 

 the juices from the inside. 



Vegetables are cooked so that the walls of the cells 

 containing starch grains may burst and permit the 

 starch to be easily acted upon by the digestive fluids of 

 the body. Boiling water will dissolve out the nutrients 

 from vegetables, so it is best to boil them rapidly or boil 

 them in just enough water to prevent burning. Potatoes 

 boiled in just enough water to prevent burning will be 

 dry and mealy. They will have a good taste and will be 

 easily digested. Vegetables should be cooked with the 

 outer skin left on when this is possible. 



QUESTIONS AND EXERCISES 



1. Point out the ways in which your body can be compared 

 to an engine. 



2. Name the activities of a living body which are necessary 

 for life. 



3. Compare the meanings of "nutrient" and "nutriment." 

 (See glossary.) 



4. Name some pure carbohydrates. Do you get carbohy- 

 drates from plants or from animals? 



5. Is fat used for the same purpose in our bodies as carbohy- 

 drates ? 



6. Compare the uses which the body makes of proteins with 

 the uses made of fats and carbohydrates. 



