20 



HUMAN PHYSIOLOGY 



CHAP. 



oats, rice, potatoes, tapioca, etc. Some fruits contain 

 considerable sugar. Carbohydrates are heat and energy 

 producing foods and should form the bulk of our daily 

 meals. They are quite easily prepared for the blood 

 and readily oxidized in the cells. 



1. Take a little common starch and boil it for a few minutes. 

 Then add a few drops of iodine solution. Notice the characteristic 

 blue color. 



2. Test other foods that contain starch in a similar way. 



23. Fats. All meats and nearly all vegetables con- 

 tain more or less fat and oil, so it is really impossible 



- to avoid fats. Pork, 



^ ' butter, lard, suet, 

 olive oil, etc., are 

 rich in fats and 

 oils. Fats are very 

 important heat- 

 producing foods, 

 but they are not 

 as easily digested 

 as proteids or 

 starches, and hence 

 should not form a 

 very large part of 

 our meals. In the 

 winter and in very 

 cold countries people eat considerable fats and oils. 



24. Water. When we remember that about three 

 fourths of the human body is water, we can see how 

 important it must be as a food. Nearly everything 



FIG. 6. Fat meat as it appears under the 

 microscope (Buchholz). 



