248 ELEMENTS OF PHYSIOLOGY 



446. Three Kinds of Flour. There are three ways of 

 grinding flour: (i) Using the whole grain and the husk 

 which incloses the grain. This makes graham flour. 

 (2) By using the whole of the grain. This makes whole 

 wheat flour. (3) By rejecting the outer and darker portion 

 of the grain, thus losing part of the gluten and retaining all 

 of the starch. This makes the ordinary flour. Graham 

 flour is most stimulating to peristalsis in the canal. Its 

 large amount of waste matter furnishes something for the 

 intestine to contract upon, and thus sweep all waste matter 

 on and out of the body, contributing to the cleanliness 

 of the canal. It sometimes causes congestion in irritable 

 stomachs. Sometimes flour which is merely dark with dirt 

 is sold for graham flour. The whole wheat flour is stimu- 

 lating to the canal but is not irritating. Some believe that 

 it furnishes more of the mineral salts and bone-making and 

 tissue-building material than the fine flour. 



447. The Cooking of Grains. You learned that the starch 

 of fruit, when it ripened, .was turned to sugar. Ordinary 

 cooking bursts the cells of starch in the grain and begins 

 the transformation into dextrin, a substance intermediate 

 between starch and sugar. This is a great help, for the 

 saliva does not act upon raw starch, and the pancreatic 

 juice acts only slightly and after several hours' delay. Cook- 

 ing that amounts to little more than moistening and heating 

 the starch, is a disadvantage, and makes it more likely 

 to ferment than if eaten raw ; but thorough cooking adds 

 greatly to the digestibility of starch. Oatmeal, cracked 

 wheat, and other grain foods should be cooked at least 40 

 minutes. 



448. How Grains may be made to resemble Fruit. If 

 cooked several hours, the starch of grains is so thoroughly 

 dextrinized that it is changed to sugar almost instantly 

 when brought in contact with the saliva. Grains may be 

 cooked during the preceding meal and the cooking finished 



