328 GENERAL SCIENCE 



far in excess of corn or rice. Gluten is a protein food of 

 great worth for tissue building. It is the gluten, too, that 

 gives to flour when mixed with water the peculiar consistency 

 that makes possible its being " raised" into the familiar 

 forms seen in loaves of bread and cake. When once raised, 

 and then subjected to sufficient heat in the process of baking, 

 the loaf retains its shape by reason of the hardening of 

 the gluten. The wheat kernel is rich, too, in those mineral 

 constituents which build up the bones of the human body. 

 These compounds, to become available for bone building, 

 must be dissolved. Other grains less extensively grown 

 than wheat, such as oats and rye, are also rich in gluten and 

 in mineral content. Rice is almost wholly a starch food, 

 and as such lacks in tissue-building value. 



In the milling process it is possible largely to eliminate 

 the gluten. The flour is somewhat whiter in appearance 

 and makes whiter bread, but it has less of food value. The 

 bone-building value is likely to be deficient in these white 

 flours. From the big flour mills, such as those in Minne- 

 apolis, flour is shipped to all parts of the world. The daily 

 output of one mill may be thousands of sacks. The outer 

 part of the kernel as separated from the pulp is sold as feed 

 for farm animals under the name of bran. The mill product 

 known as " shorts" contains much of the bran along with 

 considerable of adhering starchy portions. Dairymen in 

 the past have bought and fed to their cows large quantities 

 of both bran and shorts. Under stress of war conditions 

 much of these parts of the wheat^are retained in the flour 

 and other wheat products for human consumption. The old- 

 time grist-mill has largely disappeared from rural communities 

 where it was found in the earlier days. In the great wheat 

 districts the crop is loaded from elevators into cars, and 

 railway transportation enters into the problem of feeding 

 the millions who use wheat. 



