Ill 



FOODS 



Could we live on proteids 

 alone ? Yes. Yet the proteids 

 do not form an ideal food, because 

 they are not easily oxidized in 

 the body, and so are not as 

 valuable for producing heat and 

 energy as the carbohydrates and 

 fats. How much proteid, then, 

 should we eat ? The answer to 

 this question is simple. We should 

 eat just enough proteid to repair 

 the cells properly and to afford 

 sufficient material for growth. 



Obtain five cents' worth of iodine 

 from a drug store and dilute it with water 

 until it shows a light brown color. Label 

 and save for future use. 



1. Take any food that contains pro- 

 teid, as lean meat, and place it in a strong 

 iodine solution for a short time. Notice 

 how brown it becomes. What do you 

 infer ? 



2. Try the white of an egg and other 

 proteids in the same 



22. Carbohydrates. This is a 

 very large class of food stuffs, in- 

 cluding starches and sugars ob- 

 tained from both the animal and 

 the vegetable kingdoms. Most 

 vegetables are rich in starches, 

 as, for example, wheat, rye, barley, 



FIG. 5. Starch as seen under 

 the microscope (Buchholz) : 

 A, potato ; B, wheat ; 

 C, corn ; and D, oats. 



